MECH 4860 Engineering Design
Final Design Report
Dust Collection System Design
Submitted to: Decor Cabinet Company Submitted by: Dustbusters – Team 4
Sergei Broeska ________________________
Sarah Haiko ________________________
Cameron Parker ________________________
Gaelen Stubson _______________________
Faculty Advisor: W.C.D. DeGagne
Submitted: Monday, December 7 th 2015
ii Executive Summary
Decor Cabinet Company in Morden, Manitoba has sponsored The Dustbusters Consulting Group through the University of Manitoba’s MECH 4860 design course. This partnership was created for the Dustbusters to conduct an engineering analysis of Decor’s current dust collection system at the door manufacturing plant. The current system requires an upgrade.
The dust collection system uses a fan to draw sawdust from workstations through ductwork to a baghouse filter where the dust and air are separated prior to returning the clean air to the building. A current system analysis identified that Decor cannot simultaneously run all the machines due to an undersized supply fan, inefficient duct runs and an undersized dust collector baghouse. Additionally, as requested be Decor, Ecogate technology was researched but is not recommended for installation due to a poor payback period of 15 years.
We recommend replacing the existing supply fan with a 200 HP New York Blower Class IV SWSI blower complete with an abort gate. The blower has a variable frequency drive controlled by a new control panel. It is recommended that the current dust collector be replaced with a Donaldson Torit 570RFWPH10, which also requires a new control panel package and rotary valve. The option to purchase a new screw conveyer with auxiliary parts is recommended.
Additionally, multiple duct runs should be upgraded to decrease pressure loss and comply with NFPA’s recommended minimum 3500 FPM duct velocity throughout the system. To decrease production downtime, new duct layouts are designed parallel to the existing ducts.
Furthermore, Decor requested we upgrade the supply air system, which currently returns cold air into the building at start-up. We recommend that they insulate the exterior duct on the return air side of the dust collector with 2 inch insulation and with an aluminum jacket. The payback period of insulating the exterior duct is within one winter season.
The total cost of all recommendations is approximately $410,000. This price excludes tax,
installation and freight fees. This report provides a recommendation that meets standards, has
adequate capacity and allows Decor to simultaneously run all woodworking machines.
iii TABLE OF CONTENTS
LIST OF FIGURES ... v
LIST OF TABLES ... vii
1.0 Introduction ... 1
1.1 Objectives ... 3
1.2 Customer Needs ... 4
1.2.1 Metrics and Technical Specifications ... 5
1.3 Constraints and Limitations ... 5
1.3.1 Business Constraints ... 6
1.3.2 Technical Constraints ... 6
1.3.3 Limitations ... 9
2.0 Analysis of Current System ... 10
2.1 System Requirements ... 10
2.2 System Deficiencies ... 15
2.3 Dust Collector ... 16
2.4 Ducts ... 16
2.5 Blower ... 21
2.6 Supply Air ... 21
3.0 Ecogate ... 22
3.1 Ecogate ... 22
3.2 Analysis of Ecogate ... 24
4.0 Final Design ... 26
4.1 Dust Collector Selection ... 26
4.2 Duct Design ... 30
4.2.1 Duct Sizing ... 30
4.2.2 Duct Layout ... 31
4.3 Blower Selection ... 34
4.4 Supply Air ... 38
4.5 Final Costs ... 40
iv
4.6 Implementation Plan ... 41
5.0 Conclusion and Recommendations ... 42
Appendix A: Duct Sizing Calculations ... 45
Appendix B: Nederman Quotation for Ecogate ... 54
Appendix C: Concept Selection ... 59
Appendix D: Dust Collector Research... 65
Appendix E: Dust Collector Analysis ... 70
Appendix F: Equipment Pricing ... 81
Appendix G: Blower Selection ... 86
Appendix H: Exterior Duct Heat Loss Calculations ... 90
v
LIST OF FIGURES
Figure 1: Door manufacturing facility. ... 1
Figure 2: Existing Torit dust collector at Decor Cabinets. ... 2
Figure 3: Dust collection system ductwork. ... 2
Figure 4: Fan housing. ... 10
Figure 5: Existing facility floor layout - North side. ... 11
Figure 6: Existing facility floor layout – South side. ... 12
Figure 7: Return duct with holes cut in the sides for improved return air diffusion. ... 14
Figure 8: Existing north duct layout showing the undersized ducts represented by dashed lines. ... 19
Figure 9: Existing south duct layout showing the undersized ducts represented by dashed lines. ... 20
Figure 10: Uninsulated ducts located on the outside of the building. ... 21
Figure 11: Ecogates for ducts of different diameter. ... 22
Figure 12: Ecogate layout for typical plant. ... 23
Figure 13: New Torit dust collector. ... 27
Figure 14: New dust collector base drawings. ... 28
Figure 15: Dyna Load system diagram. ... 29
Figure 16: Rotary valve. ... 29
Figure 17: New duct layout for the north section of the Decor door plant. ... 32
Figure 18: New duct layout for the south section of the Decor door plant. ... 33
Figure 19: Fan curve for New York Blower Company supply fan. ... 35
Figure 20: Centrifugal blower from New York Blower Company. ... 36
Figure 21: Base layout of centrifugal blower. ... 36
Figure 22: Conquest abort gate diagram. ... 37
Figure 24: Location of new dust collector with reference to the current dust collector. ... 41
Figure D 1: Diagram of a cyclone dust collector……… 66
Figure D 2: Diagram of a baghouse dust collector……….. 68
Figure D 3: Diagram of a cartridge dust collector………. 69
Figure E 1: Torit model 570RFWPH10 dust collector drawing I……….. 74
vi
Figure E 2: Torit model 570RFWPH10 dust collector drawing II………. 75
Figure E 3: Rotary airlock valve……….. 76
Figure E 4: Rotary airlock valve drawing………. 77
Figure E 5: Dyna Load system diagram………. 78
Figure E 6: Backdraft damper………. 79
Figure E 7: Backdraft damper drawing………. 80
Figure G 1: Blower selection data……… 87
Figure G 2: Complete fan curve………. 88
Figure G 3: Abort gate drawings……… 89
Figure H 1: Heat transfer resistance schematics……… 90
vii
LIST OF TABLES
Table I Project Needs and Their Importance... 4
Table II Metrics and Technical Specifications ... 5
Table III Machine CFM Requirements ... 13
Table IV Summary of Total Static Pressure in the Longest Duct Runs ... 18
Table V Nederman Quote for Ecogate Package ... 24
Table VI Summary of Total Static Pressure in the Longest Duct Runs of New Duct Layout ... 34
Table VII Supply Air Insulation Analysis ... 39
Table VIII System Pricing ... 40
Table A I Existing Layout Duct Calculations……… 47
Table A II New Layout Duct Calculations………. 51
Table C I Design Options……… 59
Table C II Concept Screening Chart………. 61
Table C III Weight Analysis Chart……….. 62
Table C IV Concept Scoring Chart………. 63
Table C V Sensitivity Analysis……….. 64
Table E I Torit Dust Collector Dimensions………. 71
Table E II Torit Dust Collector Specifications……… 72
1
1.0 Introduction
Decor Cabinet Company is a leading North American cabinet manufacturer based in Morden, Manitoba. It produces wooden cabinets for a variety of kitchen styles. Each kitchen is custom made with many different personal finishes to choose from. Decor has two production facilities in Morden that are used to manufacture cabinets. The smaller facility, as seen in Figure 1, houses cabinet door production, and the larger facility houses other manufacturing processes such as cabinet assembly and finishing. Our project focuses on the cabinet door manufacturing facility.
Figure 1: Door manufacturing facility [1].
The machines in this manufacturing facility produce dust and wood chips while in operation.
The debris is currently removed using a dust collection system. Figure 2 shows the existing Torit dust collector located outside the door manufacturing facility. The dusty air is drawn from indoors to the baghouse via the blue inlet on the left side. The debris is separated by
centrifugal force and filter bags, and then transported through the auger below the baghouse to collection bins. Once the dust is removed, the air is returned to the building via the
ductwork and supply fan to the right of the baghouse.
2
Figure 2: Existing Torit dust collector at Decor Cabinets [1].
Figure 3 shows the dust collection ductwork connecting from the machines to the main
branches. There is a pneumatically operated blast gate shown in the ductwork, which is used to control the air suction to three machines.
Figure 3: Dust collection system ductwork [1].
Decor has added new machines since the original dust collector was installed, resulting in
insufficient suction when operating all the machines simultaneously. More specifically, the
3 moulder and the Bütfering sander cannot run simultaneously while the moulder is processing wide stock material. Wide stock material is drawer material that is greater than 7”, and some deep profile mouldings. Currently, a pneumatically operated blast gate controls the dust collection from these machines, as shown in Figure 3.
1.1 Objectives
The project entails a formal assessment of the dust collection system at Decor Cabinet
Company’s door manufacturing plant. This assessment indicates the air flow required for all the machines to operate simultaneously. The duct, blower and dust collector capacity are also found in the system analysis. Several options for a system upgrade have been explored and one recommendation will be made. These options include implementing a complete new system designed by us or changing components of the old section such as the blower or duct.
The options undergo screening and scoring based on criteria determined by the client and ourselves. Furthermore, a study into the feasibility of implementing Ecogates is included in the report.
Upon evaluation of the potential options, one design recommendations is made. The final recommendation provides capacity for the current machines, a new Komo router and an additional 20% for future expansion. The following objectives were completed during this project:
Evaluate the amount of suction required for all machines,
including the Komo router and an additional 20% suction capacity.
Evaluate the current design for problems.
Determine the size of a new dust collector.
Determine the size of a new blower.
Determine the size of ducts required for each branch.
Provide solutions to the cold supply air upon start-up.
Provide drawings of the proposed design.
Provide a detail quotation of the proposed design.
4 1.2 Customer Needs
With the project background and objectives identified, a more in depth analysis of the project requirements was conducted. This section examines the project needs specified by Decor, as well as the metrics and technical specifications required to successfully complete the project.
After meeting with the stakeholders for our project, a list of customer needs was developed.
This list of needs contains both the specific need as well as the importance of each need, which was ranked on a scale from 1 to 5. An importance rating of 5 is the highest level of importance and is considered integral to the design. Alternatively, an importance rating of 1 is the lowest level of importance. The needs and corresponding importance levels are summarized in TABLE I.
TABLE I
PROJECT NEEDS AND THEIR IMPORTANCE
Label Needs Importance
1. The system collects dust 5
2. All machines in the door plant can run simultaneously 5
3. The dust collector operates normally outside 5
4. The system detects sparks in the ductwork 5
5. The system is compatible with the existing electrical service 5 6. The system meets all applicable Manitoba codes and standards 5
7. The system returns air back to the space 4
8. The system has a summer and winter mode 3
9. The system is easily maintained 3
10. The system is easily turned off and on 3
11 The system returns room temperature air after start-up 3 12. The system is economical to implement and operate 2
The needs listed in TABLE I are important to successfully design a dust collection system that
will operate in Decor’s door fabricating facility. The needs listed with a 5 importance must be
incorporated into our design since they are critical to the function and performance of the dust
collection system. The needs with an importance of a 1 or 2 are not required for the dust
collection system, but Decor has asked that they be examined as possible options. Decor has
5 also asked that the air from the dust collector be returned to the space during the winters, but be exhausted during the summers.
1.2.1 Metrics and Technical Specifications
Once the project needs were established, a list of metrics and technical specifications were developed. The project metrics are complete, dependant variables that quantify what the end product will need to do. The metrics for our dust collection system are summarized in TABLE II.
TABLE II
METRICS AND TECHNICAL SPECIFICATIONS
Label Needs
#’s Metric Unit Technical
Specification
1. 1, 6 Minimum velocity of air in duct FPM 3500
2. 1, 2 Total capacity of dust collection system CFM 52320 3. 6, 7 Minimum size of dust particles collected and
retained
Microns 10
4. 9 Maximum time to service dust collector Hours 4
5. 3 Minimum outdoor air operating temperature °F -40
6. 7, 11 Minimum return air temperature °F 60
7. 5 New equipment electrical requirements Volts/Phase 600/3 8. 10 Maximum time to turn on dust collection system s 5
9. 4 Sparks are detected and extinguished - Yes/no
10. 12 Cost of the project is approved by the client $ Yes/no
11. 8 Has a summer and winter mode - Yes
1.3 Constraints and Limitations
The constraints and limitations were identified after the first meeting between our team and Decor Cabinet Company. Some constraints such as standard compliance required extensive research. Constraints and limitations were important to identify in the beginning of the design process because they narrowed the scope for concept generation.
The constraints and limitations are divided into two categories. The dust collector system
limitations are categorized as physically bounding limits. The constraints are categorized as
external factors such as Decor’s requests and engineering/safety standards that propose
6 guidelines to follow when designing dust collection systems. The constraints are further broken down into technical and business sub-categories.
The constraints and limitations for the project are listed in bullets. An explanation following each bullet outlines the importance of the constraint or limitation.
1.3.1 Business Constraints
Business constraints include the following:
Time
The first meeting with Decor took place on September 22 nd 2015. The final recommendation is due on December 7 th 2015.
Client Requests no operational downtime
Decor does not want to stop or decrease production for the upgrade of their dust collection system. This was a major factor in concept screening and selection.
1.3.2 Technical Constraints
Technical Constraints include the following:
National Fire Code of Canada [2]
The National Fire Code of Canada cites that NFPA 664 should be consulted for installing any machine that produces wood dust [3].
National Fire Protection Association(NFPA) 664 – Standard for the Prevention of Fire and Dust Explosions from The Manufacturing, Processing, and Handling of
Combustible Particulate Solids [3]
This standard applies to woodworking operations that produce more than 1500 CFM of dust. The following sections within NFPA 664 are applicable to the design.
8.1 General: This section discusses general hazards and requirements of wood
processes.
7
8.2.2.2 Duct System: This section guides what materials are appropriate and what requirements the airflow must have. It also discusses spark detection requirements the system must incorporate.
8.2.2.4 Fans or Blowers: This section discusses the design criteria of the blower, moisture content being conveyed and airflow required.
8.2.2.5 Dust Collectors: Included in this section are structure requirements, performance requirements and auxiliary requirements for the system, including the motor.
A.8.2.2.2.1.6
This section applies to the Ecogate system that was explored as a possible recommended for installation.
“An automatic damper that is located in a branch duct and dedicated to an individual woodworking machine and that opens when a machine is activated and closes when the machine is deactivated, should not be used if it will cause insufficient velocity (less than 20m/sec ~ 4000ft/min) in the main duct” [3].
Furthermore it states that variable speed controllers should not be used if it also leads to insufficient velocity within the ducts. It does state that the following methods can be implemented in a dust collection system [3].
(1) Automatic dampers can be used in conjunction with a speed controller (if the main branch pipe with the damper does not feed into the main duct but goes directly to the dust collector)
(2) Programmable controllers may be used in conjunction with dampers (3) “Other engineered systems that maintain design velocity” [3]
Canadian and Manitoba Provincial Building Codes [4], [5]
Fire and building codes were consulted to ensure the design is compliant with regulatory
codes.
8
Layout of building and machine layout is not to change
Decor asked that we do not change the machine or shop floor layout for the door
manufacturing facility. This would lead to an increase in installation time and change the entire workflow. Changing the workflow and process is not in our scope.
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 55 [6]
ASHRAE is a group of members that focus on the advancement of building systems relating to heating, ventilation and air conditioning (HVAC). This is achieved primarily through research and the publishing of standards used in the design of HVAC systems.
ASHRAE 55 Thermal Environmental Conditions for Human Occupancy provides a
standard for factors affecting thermal environmental conditions in an occupied space.
This standard is relevant to the dust collection system because the filtered air is returned back to the occupied space. Heating of the air is required at start-up on days when the indoor temperature is too low for human comfort. ASHRAE 55 discusses thermal comfort: “Thermal comfort is that condition of mind that expresses satisfaction with the thermal environment. Because there are large variations, both physiologically and psychologically, from person to person, it is difficult to satisfy everyone in a space” [6].
This standard guides the designer in thermal comfort engineering by quantifying factors such as activity level, temperature and clothing. The ASHRAE sections that we consulted for our design are as follows:
5.2 Method for Determining Acceptable Thermal Conditions in Occupied Spaces
5.3 Optional Method for Determining Acceptable Thermal Conditions in Naturally Conditioned Spaces
5.4 Description of Thermal Environment Variables
Appendix A Activity Levels
Appendix B Clothing Insulation
Appendix C Acceptable Approximation for Operative Temperature
9 1.3.3 Limitations
The project limitations include:
Baghouse height (Approximately 45 feet)
The dust collection blower and baghouse must remain outside due to noise issues and height issues. These components are too large to be located inside.
Building Electrical Supply (600 Volts)
If new equipment is required, the electrical load should be monitored. The electrical
supply should not be overloaded.
10
2.0 Analysis of Current System
This section identifies what the current dust collection system is capable of. Section 2.1 identifies the requirements the dust collector must meet based on wood working machine specifications. Section 2.2 highlights any deficiencies and is followed by several sections that explain details of the deficiencies.
2.1 System Requirements
The current system consists of one dust collector and one fixed drive supply fan located outside the building, as seen in Figure 4.
Figure 4: Fan housing [1].
The dust collector is connected to a main 36 inch diameter duct that splits into a 22 inch diameter duct and a 28 inch diameter duct. The 22 inch diameter duct is designated for the south end of the facility, and the 28 inch duct is designated for the north end of the facility as seen in Figure 5 and Figure 6. In these figures, all machines are labelled with a number, which can be referenced to the machine list in Table III. All ducts are represented by red lines and the return air is represented by the teal lines on the right hand side of Figure 5.
.
11
Figure 5: Existing facility floor layout - North side [1].
12
Figure 6: Existing facility floor layout – South side [1].
The current state analysis consisted of finding the airflow required at each workstation
identified in Table III. This was done by examining equipment manuals and by calculating flow
rates dependant on duct sizes and velocity. The American Conference of Governmental
Industrial Hygienists (ACGIH) manual was also consulted for equipment with unknown CFM
requirements [7]. A summary of the current machines at the door manufacturing plant is shown
in Table III. The current dust collection system has no automatic gates or controls to close off
unused ducts.
13
Table III
MACHINE CFM REQUIREMENTS
Drawing
Reference Machine Exhaust Flow
Rate (CFM) Total CFM Utilization Used CFM
26 Powermat 1000 moulder 6*1050 6300 0.75 4725
7 Costa planer/sander 7800 0.5 3900
1 Butfering sander, 55" roller 7000 7000 0.7 4900
28 Rairman Rip Saw 2000 2000 0.7 1400
27 Centauro band saw 1250 1250 0.05 62.5
25 Dimter chopsaw 1500 1500 0.6 900
24 KNA chopsaw 392 392 0.6 235.2
23 Quickwood sander 3X 337, 1X 150 1150 0.05 57.5
14, 15 Unique tool company double end tennoner (x 2)
1600/machine 3200 0.6 1920
17 590 router 490 490 0.05 24.5
12 Single end tennoner 1000 1000 0.55 550
11 Arch shaper 588 588 0.1 58.8
6 Saw stop (#2) table saw 350 350 0.7 245
5 Original radial arm saw, 12" D Blade
500 500 0.6 300
8 Ru Long shaper 680 680 0.7 476
2 Voorwood 1 800 800 0.75 600
4 Voorwood 2 800 800 0 0
10 Band saw 550 550 0.05 27.5
16 Frame router 350 to 800 500 0.25 125
9 D32 milwaukee
router/shaper
350 to 800 500 0.05 25
13 20" Disk sander 550 550 0.25 137.5
3 Progress miter door belt sander 6" width belt
135 CFM per ft of hood length
350 0.4 140
18 General table saw (#3) 10"
blade diameter
400 400 0.4 160
20 Boat maker 100 100 0.05 5
19 Dewalt 10” chop saw 100 100 0.1 10
21 IMC chopsaw 700 700 0.6 420
22 Accusystems MMTJ miter mortise and tenon
2600 2600 0.25 650
29 Band Saw 550 550 0.05 27.5
14 Drawing
Reference Machine Exhaust Flow
Rate (CFM) Total CFM Utilization Used CFM
N/A Komo router 900 900 0.6 540
N/A Additional 20% 8720 1 8720
Total CFM 52320 31342
Difference Between Maximum and Minimum Required Air Flow (CFM): 20978
The total requirement of the current system with consideration for future expansion is
approximately 53,000 CFM. The 20% CFM expansion accounts for other machines that could be added in the future.
The return air system functions as a dedicated path for the air to return to the building once it has been separated from the dust in the dust collector. Decor’s issue with the return air system is magnified during the late fall, winter, and early spring when the outdoor temperatures are below 10°C. When the dust collection system is started in the morning, the components located outdoors are in thermal equilibrium with the air outside. As a result, the warm indoor air that passes through the outdoor dust collector, fan and duct work is cooled to as low as -30°C before it is returned to the building. The cold return air is making the building uncomfortable for the employees to work in until the outdoor components heat up. Decor has attempted to improve this problem by diffusing the return air as high as possible along the length of the north shop wall. The air diffusers are shown as small black holes along the duct in Figure 7.
While this has helped, it has not completely solved the problem.
Figure 7: Return duct with holes cut in the sides for improved return air diffusion [1].
15 Since ducts transport dust to the dust filter baghouse there is a risk of dust exploding if an ignition source is present. As a safety precaution, Decor has an existing spark detection system in the cabinet door plant. Decor and NFPA has stated that the dust collection system must always have a spark detection system [3]. Spark detection systems have three main
components that allow the system to detect sparks in the ducts and extinguish them before they reach the dust collector [8]. The first sensors are the detector heads, which sense optical radiation produced by burning particles. The detector heads are connected to a central control unit where the signals sent from the detector heads are processed. In the event that the detector heads sense a spark, the control unit will then send a signal to the extinguishing system. The extinguishing system would open a solenoid controlled nozzle and spray a curtain of water in the duct to eliminate the spark. The detector heads and spray nozzles in Decor’s system are located in the main 36” duct leading to the dust collector.
2.2 System Deficiencies
The current state analysis identified the following deficiencies:
The dust collector is approaching maximum capacity
There are undersized ducts
The supply fan is undersized
The return air is uncomfortable to employees during winter startups
The total air flow required from the current state analysis indicates that the system is under capacity. The current dust collection system is only rated for 28,880 CFM. Furthermore, the current supply fan is only rated for 25,000 CFM. The undersized fan solidifies the need for an upgrade to the dust collection system since the most important objective of this project is to have all machines running simultaneously. Since Decor also plans to expand its current capacity by 20%, all options were explored in concept screening and scoring. An additional 20% capacity above the current system requirements would mean that the dust collection system would have to be sized for at least 52,320 CFM.
The current dust collector has approached its maximum capacity. The associated ducts have
also reached full capacity. A design with the required capacity will impact the main branches of
the ductwork since they will experience the largest increase in flow and will therefore be
16 undersized. An undersized duct has adverse effects such as excessive amounts of static
pressure. Excessive static pressure is caused by high air velocities, which lead to noise
(whistling) and possibly the physical failure of ducts. The large static pressure would ultimately increase the size of the fan required and the amount of electricity consumed by the fan.
Therefore, several ducts should be resized. Upgrading ducts will enable the system to function efficiently and at full capacity.
2.3 Dust Collector
The required airflow is approximately 53,000 CFM, as determined in Table III. The current dust collector is a 232RFW-12 walk-in baghouse. Air to media ratio and can velocity are two criteria that determine the capacity of the dust collector. The air to media ratio is the capacity of the baghouse in CFM dived by the filter bags square footage. The filter area for the 232RFW-12 is 3,622 ft 2 [9], which yields an air to media ratio of 14.6:1. However, the recommended range for air to media ratios is between 7:1 to 8:1. The can velocity is the velocity of the air inside the dust collector. The can velocity is found by dividing the airflow capacity by the cross-sectional area of the baghouse. With a can diameter of 10.25 ft. [9], the velocity is 642 FPM. The can velocity for the required CFM is much higher than the recommended 350 FPM. Running the dust collector at this airflow will greatly increase the static pressure, thus adding load to the blower, and decrease the filter bag life, which increases maintenance. At the recommended maximum velocity, the allowable airflow is 28,880 CFM, which is much less than the required 53,000 CFM.
2.4 Ducts
The current dust collection system is severely under capacity and requires an increase in air flow in order for all of the woodworking machines to operate simultaneously. With respect to the existing ductwork, there are two significant problems that can occur as a result of
increasing the air flow passing through the ducts. The first problem is that increasing the air
flow can cause excessive levels of noise due to the higher velocity of the air moving through the
ducts. The second problem is that as the velocity of the air in the ducts increases, the static
pressure in the duct also increases. Static pressure in a duct describes the amount of resistance
17 the air has to flow through the duct. An increase in the resistance would increase the load on the supply fan, resulting in a higher electricity draw. While the noise level generated in the ducts is very difficult to determine analytically, the static pressure in the duct sections is not.
The static pressure in any round sheet metal duct section can be determined using Equation 1.
𝑆𝑃 = 1.09136 ∙ 𝑞 1.9 𝑑 5.02 ∙ 𝐿
100
Equation 1
Where:
𝑆𝑃 = Static Pressure [in. wg]
𝑞 = Air Flow Rate [CFM]
𝑑 = Duct Diameter [in]
𝐿 = Duct Length [ft]
In order to analyse the current system, we were required to find the total combined static
pressure of each different series of ducts. Once the static pressure of each series of ducts is
found, the series with the largest static pressure determines the maximum static pressure of
the system. This series of ductwork is referred to as the worst case duct run. Since there are 30
machines in the Decor plant, there will be 30 different series of ducts to analyse. However,
many duct runs are very short when compared to other runs and therefore, will have a much
lower static pressure. Due to this, the static pressures for only the longest duct runs were
calculated. For existing machines that do not currently have dust collection it was assumed that
their ducts would simply be tied into the nearest duct branch. Following this methodology the
worst duct runs were calculated and summarized in TABLE IV. The details for how the static
pressure for each duct run was calculated can be found in Appendix A.
18
TABLE IV
SUMMARY OF TOTAL STATIC PRESSURE IN THE LONGEST DUCT RUNS
Starting Machine
Static Pressure in Suction Ducts
[in.wg]
Static Pressure in Return Ducts
[in.wg]
Static Pressure in Baghouse
[in.wg]
Total Static Pressure
[in.wg]
1. Butfering
Sander 2.5 1.8 1.3 5.6
3. Miter Door
Sander 11.6 1.8 1.3 14.6
9. Router/ Shaper 20.2 1.8 1.3 23.3
26. Powermat
Moulder 5.6 1.8 1.3 8.7
28. Raiman
Ripsaw 5.9 1.8 1.3 9.0
TABLE IV shows the highest static pressure of 23.3 in.wg occurs in the duct run connected to
machine 9. Router/ Shaper. This static pressure would only occur if the system capacity was
increased to the required air flow of 43,600 CFM. A static pressure of 23.3 in.wg is extremely
high and proves that the existing ducts are not large enough to accommodate the increased
capacity requirements. Figure 8 and Figure 9 show the existing duct layout for the north and
south section of the plant, respectively. Ducts drawn as a dashed line are the sections of duct
that would be undersized for the increase in capacity.
19
Figure 8: Existing north duct layout showing the undersized ducts represented by dashed lines [1].
20
Figure 9: Existing south duct layout showing the undersized ducts represented by dashed lines [1].
21 2.5 Blower
The existing blower is rated for 25,000 CFM at 14 in.wg static pressure, and 100 HP [10]. This is less than half of the required airflow, 53,000 CFM, given in Table III.
2.6 Supply Air
During the winter months the start-up supply air conditions are uncomfortable to Decor’s workers. We expected that this problem was caused by the large amount of cold air contained within the dust collector. Upon start-up the presence of this cold air is unavoidable because this air is located in the dust collector, which is outside cooling during the night. However, Decor told us that the outside ducts are not insulated, thus by insulating the ducts we believe that the start-up warm up time can be reduced and total energy savings during the winter months can be increased. Figure 10 shows the uninsulated ducts that are located outside of the building.
Figure 10: Uninsulated ducts located on the outside of the building [1].
22
3.0 Ecogate
3.1 Ecogate
The current system for controlling the opening and closing of duct gates is a manual operation;
a person must manually engage a switch to open and close blast gates. This is not an efficient method because it is not automated and does not take into account velocity, pressure or flow rate. Therefore, as Decor suggested, the Ecogate system was considered. Ecogate is the brand name for a system of automated blast gates that are controlled by a computer.
An Ecogate system can reduce Decors energy consumption by adjusting the air flow in the ducts based on the required air flow. If fewer machines are being used, less air flow is required and vice versa. The system also makes the dust collection system more flexible and controllable since suction can be shut down to machines during maintenance without interrupting other operations. Local sensors identify if the machine is running and communicate with a master computer, called the GreenBox master, to determine the speed of the blower. Using this system also requires a variable frequency drive (VFD) blower to control the amount of air drawn through the system. The current system uses a fixed speed blower and meaning it is not compatible with the Ecogate system. Therefore, a compatible blower must be purchased. The gates that block the ducts come in a range of sizes. Figure 11 shows a range of gates.
Figure 11: Ecogates for ducts of different diameter [11, used with permission of Ecogate].
23 A single greenBox master can control up to 4 blowers and 130 gates, which easily allows for expansion that Decor desires. The smart gates monitor air pressure, velocity and
flow (EcoGate). The gates come in many sizes ranging from 4 inch to 18 inch. Ecogate complies with NFPA and OSHA rules and regulations. Figure 12 shows how the different components of Ecogate’s technology interact with each other.
Figure 12: Ecogate layout for typical plant [12, used with permission of Egogate].
Although Ecogate would be a nice addition to Decors dust collection system, the payback
period was too long. Therefore, we do not recommend installing an Ecogate system. The next
section summarizes the quotation for Ecogate along with the payback analysis.
24 3.2 Analysis of Ecogate
Table V is a summary of Nederman’s quotation for an Ecogate package for Decor Cabinet Companies Dust Collection System:
Table V
NEDERMAN QUOTE FOR ECOGATE PACKAGE
Quantity Description [12]
32 Gates ranging in size from 4” to 18”
1 GreenBOX Master SRL 100 for controlling the velocities in the ducts 1 Negative Pressure Sensor
1 Ecogate Power MASTER, 200HP 575V Dustproof cabinet – controls VFD motor 1 Ecogate data mining subscription
32 Hawkeye Current Sensors 1 Installation Material including:
1500 feet of sensor cable for workstations 500 feet of sensor cable for Fan – outdoor rated 3500 feet of Ecogate Green Cable
1 Verification of installation Total Cost of materials: $ 136,660.00
Nederman also provided a savings forecast based on the machines running 15 hours per day, 5 days per week, 52 weeks per year with an electricity rate of $0.037/kWh. In order to maximize savings, it would be beneficial to downsize the 46 inch diameter main duct to a 40 inch main duct in order to maintain velocities when gates shut as per NFPA 664 requirements. If the main duct was left at a 46 inch diameter the system would only be able to achieve a 43% in potential savings as opposed to a 75% potential savings based on a 40 inch diameter main duct.
The savings based on a 40 inch diameter main duct are $9,395.00 per year [12]. The payback
period is calculated below. For the payback analysis we assumed zero inflation, and ignored the
cost of capital, construction costs, taxes and production losses due to installation.
25 𝑃𝑎𝑦𝑏𝑎𝑐𝑘 𝑃𝑒𝑟𝑖𝑜𝑑 (𝑌𝑒𝑎𝑟𝑠) = 𝑇𝑜𝑡𝑎𝑙 𝐶𝑜𝑠𝑡 𝑜𝑓 𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙𝑠
𝑆𝑎𝑣𝑖𝑛𝑔𝑠 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 For $0.037/kWh:
𝑃𝑎𝑦𝑏𝑎𝑐𝑘 𝑃𝑒𝑟𝑖𝑜𝑑 (𝑌𝑒𝑎𝑟𝑠) = $136,660.00
$9,395.00 𝑦𝑒𝑎𝑟
= 14.5 𝑦𝑒𝑎𝑟𝑠
The rate used in the previous calculation was $0.037/kWh. We found that Decor has a weighted average electricity rate of $0.04575/kWh. The adjusted payback period using Decor’s electricity rate is calculated below:
𝑃𝑎𝑦𝑏𝑎𝑐𝑘 𝑃𝑒𝑟𝑖𝑜𝑑 (𝑌𝑒𝑎𝑟𝑠) = $136,660.00 0.04575
0.037 ∙
$9,395.00 𝑦𝑒𝑎𝑟
= 11.8 𝑦𝑒𝑎𝑟𝑠
Even though the adjusted payback period is less than the original payback period, this
investment into Ecogate technology is not in Decor’s best interest. If we were to account for the installation costs, taxes, loss in production costs and incorporate the time value of money into the formula the payback period would be even longer. Therefore, we do not recommend implementing Ecogate technology. The full quotation package is found in Appendix B.
The remainder of the options considered for the final recommendation include various
combinations of interchangeable components such as the blower, dust collector and ductwork.
The screening and scoring of the possible options can be found in Appendix C.
26
4.0 Final Design
For our final design we have chosen option 4 of the listed options in Appendix C. This option requires a larger dust collector, a new blower fan and new ducts to accommodate for the increased capacity. Existing ducts will be reused if they are suitable for the design. The final design is broken up into four major components: the dust collector, ducts, blower and supply air system. The dust collector consists of the baghouse and any associated structural material.
The ducts consist of any duct that transports dust from a wood working machine to the baghouse. The blower includes the fan, motor and associated items. The supply air system consists of the ducts that return filtered air from the baghouse back into the building.
The original plan was to recommend a short term (option 11) and long-term (option 4) plan for Decor. However, only one recommendation will be made after identifying issues with the short- term plan. The short-term plan consisted of installing a new supply fan and upgrading certain ducts. Proceeding with this plan would overload the current baghouse past its allowable capacity. This design would also put an undesirable load on the fan due to excessive static pressure.
Our recommended design will allow Decor to run their door manufacturing plant at full capacity. This design will ensure appropriate static pressure on the dust collector and increase the efficiency of the system.
4.1 Dust Collector Selection
We decided to use the same manufacturer as the existing Torit baghouse to satisfy the need for a new dust collector. Research regarding different types of dust collectors can be found in Appendix D. Sections of the Donaldson Torit brochure used to select the model are given in Appendix E. The size of the baghouse was determined using the required airflow of the system, which is given in Table III.
Firstly, capacity of the model is found using an air to media ratio of approximately 8:1 [13]. This
means the volume of air flowing through the baghouse in CFM should be no more than eight
times the area of the filter media in square feet. Next, the velocity in the can of the dust
27 collector needs to be below 350 FPM. The velocity is found using the airflow capacity and the cross-sectional area of the baghouse. Dimensions of each model are given in the Torit
brochure. Complete calculations regarding the dust collector selection are given in Appendix E.
The Torit baghouse is shown in Figure 13. A summary of the selected dust collector model is as follows:
Manufacturer: Donaldson Torit
Model: 570RFWPH10
Filter Area: 7,410 ft 2
Airflow: 55,000 CFM
Air to Media Ratio: 7.4:1
Can Diameter: 188 in
Can Velocity: 275 FPM
Figure 13: New Torit dust collector [9].
28 The baghouse must be placed on a concrete pad or concrete piles in order to support the weight. The base dimensions and anchor bold pattern are given in Figure 14. The weight of the dust collector is 40,049 lbs [9].
Figure 14: New dust collector base drawings [13, used with permission of Conquest Equipment Corporation].
A number of additional items are to accompany the installation of a new dust collector, some required and some optional. They are as follows:
Required
Control panel package
Rotary valve
Optional
Screw conveyor
Splitter screw conveyor
Splitter support stand
Spreader covers
Backdraft dampers
29 The control panel package includes a variable frequency drive (VFD) on the fan and airflow sensors. The system controls the amount of provided airflow and reduces the load on the fan during start-up, which results in potential energy savings as well as increased filter life.
The rotary valve, screw conveyor, support stand and spread covers setup is illustrated in Figure 15.
Figure 15: Dyna Load system diagram [13, used with permission of Conquest Equipment Corporation].
The rotary valve, or airlock, shown in Figure 16, provides explosion isolation in accordance with NFPA 654, as well as allowing waste to be removed from the dust collector while in operation.
The conveyors transfer the dust from the dust collector to the roll off containers.
Figure 16: Rotary valve [13, used with permission of Conquest Equipment Corporation].
611 Argyle St. N. Caledonia, Ontario N3W 1M1 TEL: (800) 655-3447 FAX: (800) 955-4991
Email: [email protected] Website: www.acsvalves.com
CI Series Rotary
Airlock Valve
Drop-Thru Feeder/ Airlock
Features Options ___
• Available in 10 sizes
• Dependable effective design
• Heavy duty rugged construction
• Precision machining of components
• Unique shaft seal design
• Pressure differentials up to 15 psig
• Square flanges
• High temperature options up to 750 F
• Available in cast iron, 304 SS and 316 SS
• Standard 8-vane rotor design comes complete with beveled tips and sides, option 6-vane available
• ACST-4 shaft seal or ACS Packing gland shaft seals available
• Housing vent ports
• Surge hoppers, blow through adapters, shear plate deflectors
• Rotor options: closed end, metering style, shallow pocket, adjustable tips, teflon coated
• Adjustable rotor tips available in EPDM, hardened steel, stainless steel, bronze, polyurethane
• Interior coating options: hard chrome, tungsten, and teflon
• Shaft seal and rotor pocket air purge
• Special drive packages
• Motion speed switch assemblies
30 The backdraft damper is installed on the inlet to the dust collector. The damper closes if a back draft of explosion occurs so that air and debris cannot enter the building. Further information regarding the system components is given in Appendix E and Appendix F.
4.2 Duct Design
As shown in section 2.4 much of the existing ducts in Decor’s door plant are too small to accommodate the increased capacity required for the new dust collection system. In order for the new system to operate properly, many of the existing ducts should be changed to a larger size or re-routed to improve the systems efficiency. The following section will present a modified duct layout and discuss how the new duct sizes for the modified layout were determined. It should be noted that any existing blast gates are no longer required since the new recommended design has adequate capacity for all woodworking machines. Therefore, they can be left open.
4.2.1 Duct Sizing
Since the static pressure in the existing ducts would be too high if the capacity of the dust collection system was increased, new duct sizing is required. There were three main criteria that had to be met while resizing the ducts. The first criterion was to utilize as much of the existing ducts as possible. By minimizing the amount of ducts that needed to be removed, we could not only minimize the construction cost of the project but also decrease the chance that the plant would have to shut down for construction. The second criterion was to maintain a minimum air velocity of 3500 FPM. A velocity below 3500 FPM would allow the large wood chips from the machine to settle out in the ducts, causing a blockage and a severe fire hazard.
The air velocity in a duct is calculated using Equation 2.
𝑣 = 4 ∙ 𝑞 𝜋𝑑 2 Where:
𝑣 = Air Velocity [FPM]
𝑞 = Air Flow Rate [CFM]
𝑑 = Duct Diameter [ft]
Equation 2
31 The final criterion is to minimize the static pressure generated in each section of duct. Keeping the static pressure as low as possible would create a more efficient system and allow for a smaller supply fan to be selected.
4.2.2 Duct Layout
Using the criteria outlined in section 4.2.1, a modified duct layout was generated. The first step to generating the new layout was to sketch a new layout on the existing drawing. Using Table III the required machine air flows were added to the sketch in order to determine the amount of air flowing through each section of the proposed duct. Next, using Equation 1 and Equation 2, the optimal duct size for each section of duct was selected by minimizing the static pressure.
The air velocity was maintained at or above 3500 FPM. This was an iterative process since duct
sizes are only available in 1 inch increments from 4 – 10 inches and 2 inch increments from 10
inches and up. Once the duct sizes were determined, a comparison was made between the duct
sizes on the sketch and the existing drawing. Any existing ducts that matched the optimal sizes
on the sketch were incorporated into the new duct design. Figure 17 and Figure 18 show the
new duct layout for the north and south sections of the Decor plant respectively. It should be
noted that the new layouts have been design so that the main branches of the ducts are
located adjacent to the existing main branches. This was done so that the new ducts could be
constructed without interrupting the existing dust collection system. Once all of the main ducts
have been installed, a brief changeover period would be required to tie each of the machines to
the new main branches.
32
Figure 17: New duct layout for the north section of the Decor door plant [1].
33
Figure 18: New duct layout for the south section of the Decor door plant [1].
34 Finally, the total static pressure for the new design was calculated using the same procedure described in section 2.4. The static pressures for the longest duct runs in the new design are summarized in TABLE VI. The table showing all of the values used to calculate the total static pressure is available in Appendix A.
TABLE VI
SUMMARY OF TOTAL STATIC PRESSURE IN THE LONGEST DUCT RUNS OF NEW DUCT LAYOUT
Starting Machine
Static Pressure in Suction Ducts
[in. wg]
Static Pressure in Return Ducts
[in. wg]
Static Pressure in Baghouse
[in. wg]
Total Static Pressure
[in. wg]
3. Miter Door
Sander 5.9 1.8 1.3 8.9
9. Router/ Shaper 4.1 1.8 1.3 7.1
28. Raiman
Ripsaw 2.8 1.8 1.3 5.9
27. Centauro
Bandsaw 3.8 1.8 1.3 6.9
26. Powermat
Moulder 4.3 1.8 1.3 7.4
The recommended duct design also includes a safety feature called spark detection. A Model AN6400 spark detection system is recommended. This system will detect and extinguish sparks.
More information regarding the spark detection system can be found in Appendix F.
4.3 Blower Selection
A backward inclined blower is used as the fan for the dust collection system. The fan
performance was selected based on the airflow requirement, static pressure, and brake
horsepower. The maximum airflow required to provide suction to all the machines as well as
20% extra capacity was determined in Table III. The static pressure of the system that the
blower will need to overcome is shown in TABLE IV. The fan input power, or brake horsepower
(bhp) was determined using the fan curve in Figure 19.
35
Figure 19: Fan curve for New York Blower Company supply fan [13, used with permission of New York Blower Company].
The required power was determined by locating the intersection of the airflow requirement and the power curve, as indicated by the red line. A summary of the selected blower is as follows:
Model : New York Blower Class IV SWSI [14]
Airflow: 55,000 CFM
Static Pressure: 14 in wg
Speed: 1539 RPM
Power: 161 HP
Static Efficiency: 63 %
Outlet Velocity: 4829 FPM
Static Pressure Power
System Curve
Bold region of curves is AMCA-certified
0.0 2.5 5.0 7.5 10.0 12.5 15.0
0 25 50 75 100 125 150
0 10 20 30 40 50 60 70 80
0 10000 20000 30000 40000 50000 60000 70000 80000
The New York Blower Company
Fan-to-Size
Backward Inclined Class IV SWSI Volume Flow Rate: 55,000 CFM Temp.: 70 Deg F
446 PLR Fan Static Press.: 14.0 in wg Altitude: 950 ft
Class: 4; Arr.: 1 Speed: 1539 rpm Density: 0.0725 lb/ft3
Power: 161 bhp Outlet Velocity: 4829 ft/min
Copyright ©1999 The New York Blower Company.
[v1.86.31-R -- February 2015] Date Printed: 11/16/2015
Your Sales Representative:
Performance certified is for installation type: B - free inlet, ducted outlet.
AMCA Licensed for Air Performance without Appurtenances (Accessories). Power (bhp) excludes drives.
F a n S ta ti c P re s s u re ( in w g ) F a n In p u t P o w e r ( b h p )
S ta ti c E ff ic ie n c y ( % )
Volume Flow Rate (CFM)
Version: 1.86.31-R (February 2015) Printed: 11/16/2015 PDF. Calc Mode: Find Speed
36 The centrifugal blower complete with motor from New York Blower Company is shown in Figure 20.
Figure 20: Centrifugal blower from New York Blower Company [14].
The centrifugal blower must be placed on a concrete pad in order to support the vibration and weight. The base layout of the blower is shown in Figure 21.
Figure 21: Base layout of centrifugal blower [14].
Relevant dimensions and fan weight are as follows [14]:
U: 24 ½ in
P: 41 ¾ in
O: 58 in
Weight: 1732 LBS
Further information regarding the blower is given in Appendix G.
37 An accessory to the fan is an abort gate, which is installed in the return air duct. The abort gate diverts air outside instead of back into the building in case of a fire or during seasons when 100% outdoor air is brought into the building. A side profile of the abort gate complete with dimensions is given in Figure 22. Complete abort gate drawings are given in Appendix G.
Figure 22: Conquest abort gate diagram [13, used with permission of Conquest Equipment Corporation].
SECTION A-A
BASE CHANNELS
A A
1
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8
A A
B B
C C
D D
APPROVED BY CHECKED BY
EQUIPMENT CORPORATION
03-Sep-15
NOTES/SPECIAL INSTRUCTIONS 1-2073 LOGAN AVE.WINNIPEG, MB CANADA R2R 0J1 www.conquestequipment.com
10105 KCMC-HSAG-10105-A
JOB NO.
PROJECT
TITLE
SLM
DATE
QUANTITY DRAWN BY
SCALE
DWG NO. FOR
SHEET REV NO.
1 of 1 NTS
2 ABORT GATE 48x48 0
1
R E V I S I O N
REV DESCRIPTION DATE BY
50 8 SP @ 6-1/4 =
5 0 8 S P @ 6 -1 /4 =
48
4 8
7/16 32 HOLES
2 TYP
42
5 1
4 4
46
5 4
9/16 4 HOLES
78
98 1/4
2 6 1 /2
5 4 3 /8
1 0 1 3 /4
59 1/2 54
KCMC-HS AG-1 0 1 0 5 -A
MILD STEEL CONSTRUCTION 110V ELECTROMAGNET
NEMA 4 LIMIT SWITCH c/w NO & NC DRY CONTACTS, 110VAC JUNCTION BOX INCLUDING MAGNET RECTIFIER
MAGNET AND SWITCH WIRING TO JUNCTION BOX INCLUDED FIELD WIRING TO CONTROL PANEL NOT INCLUDED
TORIT BLUE PAINT FINISH (STANDARD CONQUEST PAINT SYSTEM) SHIPPING WT APPROX 1415 LBS EA
NOT INCLUDED: CABLING/WIRING/PLUGS, INSTALLATION, FREIGHT SCREENED EXHAUST
DUCT FLANGE
TYPICAL EACH END
GATE SHOWN IN DIVERTED POSITION
ABORT POSITION
LIMIT SWITCH MAGNET
RESET LEVER
LEVER IS RETURNEDTO REST AS SHOWN WHEN GATE IS LATCHED
IN FLOW-THRU POSITION
THE ABORT GATE IS DESIGNED TO BE FITTED INTO THE RETURN AIR DUCT JUST BEFORE ENTRY TO THE BUILDING. THE PURPOSE OF THIS DEVICE IS TO DIVERT AIR RETURN IN CASE OF FIRE, ETC. THE ABORT GATE IS NOT A STAND-ALONE DEVICE. FULL-TIME 110 VAC POWER SUPPLY IS REQUIRED AND SUPPLIED BY SYSTEM CONTROL PANEL.
ANY INTERRUPTION OF POWER WILL CAUSE THE GATE TO MOVE INTO ABORT POSITION. THE GATE WILL NOT AUTOMATICALLY RESET WITH THE RETURN OF POWER. THE LEVER MUST BE MANUALLY LIFTED AND THE BLADE LATCHED TO THE MAGNET FOR THE FLOW-THROUGH MODE TO FUNCTION.
APPROX.
85 LBS FORCE REQUIRED
TO LATCH GATE