PREPARED
BY:-DEEPAK M. BHATIA AVINASH PAL
INTRODUCTION
HISTORY:-1) In the 1940s, the USA started an extensive program to help synthetic elastomer achieve a worldwide breakthrough.
2) Using high-quality elastomer materials, new technical possibilities eventually opened up for the design and use of diaphragm pumps .
3) Later, hydraulically driven diaphragm compressors came onto the market that were able to produce high pressures of up to 4,000 bar.
PUMPS
:-1) A pump is a device used to move liquids or slurries.
2) It is used to move liquids from lower pressure to higher pressure.
DIAPHRAGM
PUMPS:-1) It’s a diaphragm pump is a positive displacement pump.
2) Uses a combination of the reciprocating action of a rubber or Teflon diaphragm and suitable non-return check valves to pump a fluid.
TYPES OF DIAPHRAGMPUMP:-1) In the first type, the diaphragm is sealed with one side in the fluid to be pumped, and the other in air or hydraulic fluid.
2) The second type of diaphragm pump works with volumetric positive
displacement, but differs that the prime mover of the diaphragm is neither oil nor air; but is electro-mechanical working through a crank/ geared motor drive.
3) The third type of diaphragm pump has one or more unsealed diaphragms with the fluid to be pumped on both sides.
HIGH-SPEED LIQUID DIAPHRAGM PUMPS
A special type of pump based on the technology of diaphragm pump.
Employs a mechanical drive for transferring, evacuating and compressing gases.
DESIGN, FUNCTION AND PROPERTIES OF
DIAPHRAGM PUMPS
1) Elastic Diaphragm 2) Pump Head
3) The Housing
4) The Connecting Rod 5) Clearance
6) The Diaphragm Fixing Screw 7) Transfer Compartment
8) Outlet Pressure Valve 9) Inlet Pressure Valve
CRITERIA FOR SELECTION OF PUMP
Type of gas
Required pneumatic performance Gas temperature
Temperature of the surroundings
Other conditions related to the surroundings Type of motor
Possible constructional parameters Mounting position and orientation Operating conditions
DESIGN OF DIAPHRAGM
Control Parameters:Maximum speed Nmax = 250 rpm Diameter to stroke ratio = D/L = 2 Maximum diameter D = 3d
Design Parameters: 1). Discharge
Discharge= Area * stroke length *speed Qmax = π/4 * d2 * L * N max
2). Chamber diameter
D = 3d
3). Chamber depth
l = L/2 + 4 mm clearance
4). Eccentricity
e = l/2
5). Control volume
= π/4 * D
2* L
MODEL PERFORMANCE CURVE
D is c h a r g e ,Q th V s . S p e e d 2 0 , 0 .2 5 7 5 0 , 0 .6 4 3 8 5 , 1 .0 9 41 0 5 , 1 .3 5 1 1 5 5 , 1 .9 9 5 1 8 5 , 2 .3 8 2 5 5 , 3 .2 8 12 7 5 , 3 .5 4 0 0 .5 1 1 .5 2 2 .5 3 3 .5 4 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 S p e e d ( r p m ) Di sc ha rg e,Q th (lp m) D is c h a r g e ,Q a c t V s . S p e e d 2 0 , 0 .2 4 5 5 0 , 0 .6 8 5 , 11 0 5 , 1 .2 1 5 5 , 1 .7 5 1 8 5 , 2 .0 5 2 5 5 , 2 .7 52 7 5 , 2 .9 0 0 .5 1 1 .5 2 2 .5 3 3 .5 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 s p e e d (rp m ) di sc ha rg e ( lp m )CONCLUSION
From the graph of discharge versus speed curve, it is noted that actual discharge deviates more and more from theoretical discharge as the speed increases, this means slip increases rapidly with higher speed.
Also the eccentric drive is there which gives more fluctuation.
A major advantage of diaphragm pumps is that the pumped liquid does not come into contact with most of the working parts of the pump.
The diaphragm pump offers further advantages over oil-lubricated pumps such as it is an Oil free pump, it has High gas tightness capacity, is highly reliable etc.
FUTURE SCOPES
Principle of diaphragm pump can be used to make miniature pump i.e. micro pump which will be useful for space and medical application. Following is the micro pump concept.
There is a range of NASA experiments, instruments and applications where miniature pumps are needed. To address such needs, a piezo electrically actuated miniature pump is being developed under a NASA Code S PIDDP task.
REFERENCES
Books
Pump Handbook-Igor J. Karassik, JOSEPH P. Messina, Paul Cooper, CHARLES C. Held.
Material selection in mechanical design-Michael & Ash Fluid Movers by Nicholas P. Chopey
Pumps & Pumping operation by Nicholas P. Pawl Metering pump handbook by Robert E. McCabe Pumping and Processing principle & practice Fluid Movers
Water well and pump Engineering by A M Michael & S D Khepar
Websites www.knf.com www.positivemetering.com www.pumps_in_stack.com/diaphragm_pump_design.html www.howstuffworks.com www.wikipedia.com www.ebookworld.com www.syudentshangout.com