InstruCalc QuickStart Guide

INSTRUCALC VERSION 9

QUICKSTART GUIDE

January 2015

1.0

START MENU

On opening InstruCalc Version 8 you will be presented with the following Main Menu giving you access to the four modules of the program:

CONTROL VALVE SIZING PROGRAM FLOW ELEMENT SIZING PROGRAMS

Each module has a New Calculation option at the top of each pane. A selection here may take you immediately to a data entry dialog (eg Control Valves) or to another menu from where you select the desired routine (eg Flow Element Sizing). After this selection routine you will be in the appropriate data entry dialog where first you must make your selection of units and other options.

For instance try:

 Control Valve Sizing  Liquid

 [New calc]

To return to the module menu use File | Program menu.

To return to the Main Menu use File | Exit

Now try:

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2.0

UNITS AND CALCULATION OPTIONS SELECTION

Once any of the four modules is activated, you need to preset your units and other data using the [Change setup] button which appears bottom right on all modules - as shown by the red arrow in the image below. It is recommended not to use the buttons on the calculation screen itself (see below) to set your initial units of choice. These buttons are for fine tuning each line after initial units selection is made on the [Change setup] screen.

Once you have selected your desired units for calculation on this screen, you may fine tune the individual input units on the calculation screen using the line item buttons as shown below.

3.0

CONTROL VALVES

The Control Valve module operates via an interaction between the two dialogs shown below, the Valve Sizing dialog and the System Pressure Drop dialog. Limited data is first entered into the Valve Sizing dialog (Normal data column), with the valve pressure drop being estimated if not known. InstruCalc allows for Normal, Minimum and Maximum flow situations to be analysed, based on a proportion of the nominal flow. It always starts with Normal flow which defaults to 50% of nominal flow.

The objective of the calculation is to first size or select a valve for Normal flow – usually considered to be 50% of a ‘nominal flow’. The software then allows for the rangeability of the selected valve to be tested, ie its effective performance with flowrates greater or less than the Normal flow. This requires the System Pressure Drop dialog to be utilised since the inlet pressure to the valve will vary with different flowrates.

VALVE SIZING DIALOG

OUTLINE

Once the first estimate of Normal flow conditions is made in the Valve Sizing dialog, the fluid and type of valve selected, and the [Normal] conditions calculated, this data is transferred to the System Pressure Drop dialog where the pressure drop along the upstream and downstream connecting pipes is determined taking into account any additional fittings. Pipe start/end upstream and downstream pressures are defined. This data is then transferred back to the Valve Sizing Normal dialog where the inlet pressure to the valve may be modified to take into account upstream pipe flow conditions.

The link is via the menu option [Other options] on the Valve Sizing dialog ...

After this stage the [Maxim] and [Minimum] flow conditions can be analysed.

SYSTEM PRESSURE DROP DIALOG

Data enter into this dialog determines upstream and downstream pipe conditions and may amend the valve inlet pressure accordingly. Calculation is via the [Normal] button at the top of the data column.

Calculated data is returned to the Valve Sizing dialog via the buttons shown below.

and returns to the Valve Sizing dialog where the [Normal] calculation needs to be repeated. Here the valve inlet pressure will be amended dependent on the defined connecting pipe flow conditions.

Once the Normal conditions have been re-calculated, the scroll bars become active. Move them up or down to calculate various percentages of Normal.

The System Pressure Drop dialog is now automatically linked, so that variations in flowrate and system properties for both the valve and the adjoining pipework are simultaneously calculated – providing a guide the rangeability of the selected valve.

Note – always move the Minimum scroll bar first, the Maximum scroll bar second.

SUMMARY

The objective of the calculation is to first size or select a valve for Normal flow – usually considered to be 50% of a ‘nominal flow’. The software then allows for the rangeability of the selected valve to be tested, ie its effective performance with flowrates greater or less than the Normal flow. This requires system pressure drop dialog to be utilised since the inlet pressure to the valve will vary with different flowrates. Finally, valve closing time may be analysed.

3.1 CONTROL VALVE: EXAMPLE 1, STEAM FLOW: STEP-BY-STEP EXAMPLE The steps described belowmust be followed precisely.

STEP ACTION IMAGE COMMENT

NORMAL FLOW VALVE SIZING - START 1 Select Control Valves from the

Main Menu and then select:  Gas, steam or vapor  [New calc]

2 Select units.

[OK]

Mass SI units will be used throughout this QuickStart Guide.

3 Enter a Tag Example 1.

4 Input in the Normal data column

- Gas flow rate

 Pressure drop (best guess)  Flow temperature

 Inlet pressure (best guess)

Pressures may be precisely known at this stage or may be refined later via the System Pressure Drop dialog.

5 Define your Normal flow fluid. _{Select superheated steam and appropriate} properties will be displayed.

6 Enter Valve Data This may be from the valve database as shown

-Standard or Lo Flow - or directly entered. Note: If selecting a valve from the database, you do not specify Size, Rated Cv or Fd as the software will determine this. Usually the valve selection will be one size less than the specified pipe nominal size.

7 Enter pipe data or leave blank. Leave blank

8 Calculate using the [Normal] button at the top of the data column.

Initial output data is calculated.

Do not use scroll bars at this point.

SYSTEM PRESSURE DROP

Note this dialog must be completed before attempting to test the rangeability of the selective valve via the

and buttons.

9 Access the System Pressure Drop dialog.

10 Enter the piping configuration data in the left hand side panes.

This sets up the pipe system in which the valve sits and allows for the accurate calculation of inlet pressure to the valve for the three calculations. We are assuming no pipe fittings and accessing accurate pipe size data from the underlying database. Or pipe size can be entered directly.

11 Enter the Source and Destination pressures for Normal flow only.

The Normal flow value is carried over from the Valve Sizing dialog.

12 Enter any additional Inlet and Outlet equipment losses

None 13 Calculate the system for normal

flow.

Use the button at the top of the data column. Precise Normal output data is now calculated for transfer back to the Control Valve dialog

14 Transfer the Normal flow data back to the Valve Sizing dialog.

16 Now activate the scroll bars using the Minimum data column first.

Always activate the Minimum scroll bar first. Scroll up on the Maximum data column to find the maximum flowrate the selected valve can take Scroll the Minimum data column for the minimum allowable flow.

17 Test the rangeability of the valve by increasing the Maximum flow to a maximum.

At 76% of the nominal flow, the selected valve is too small.

18 Add some identifying data in the Notes rows and plot the valve charts.

Select different charts for the menu options at the top.

3.2 CONTROL VALVE: EXAMPLE 2, WATER FLOW 1 Input in the Normal data

column

- Liquid flow rate

 Pressure drop (best guess)  Flow temperature

 Inlet pressure (best guess) As shown in the image opposite.

2 Select water as the liquid and a butterfly valve.

3 Calculate [Normal] flow to get the image shown in Step 1. 4 Enter upstream and

downstream pipe data.

5 Re-calculate Normal, maximum and Minimum conditions.

Note that InstruCalc has selected an appropriate valve size for the conditions shown.

6 Increase the Maximum flow to 70% of nominal.

InstruCalc shows that the valve is too small. Select the choice to use a larger valve…

[Yes]

Note the valve size has increased to 100mm.

4.0

ORIFICE PLATE CALCULATION - LIQUID FLOW

Calculation shown opposite.

2 [Change setup] Note the options here, particularly the

choice of three calculations available:  Calculate differential range  Calculate flowrate

3 Enter the data as shown then select water.

4 Specify the pipe material, ID and element material and calculate

5.0

RELIEF VALVES

The Relief Valve module offers a variety of relief valve type calculations for determining the appropriate area of flow, viz:

The Relief Valve module operates via an interaction between the two dialogs shown below, the Area Sizing dialog on the left and the Pipe Loss dialog on the right. The link is via the menu

option [Pipe losses] on the Area Sizing dialog…

…and the Transfer button on the Pipe Loss dialog.

The step-by-step process described below must be followed precisely and specifically applies to a Steam Relief – Known flow.

STEP ACTION IMAGE COMMENT

AREA SIZING

1

4 Select ASME Section 8, Balanced Bellows and no Rupture disk

5 Enter initial data. Note Percent Overpressure and Valve discharge coefficient have default values. These can be over-written.

6 Calculate to display valve area.

7 ...and Output Data Note: InstruCalc calculates the Valve Capacity – it’s on this value that the valve is sized.

PIPE LOSS

8 Access the System Pressure Drop dialog.

9 Enter the piping configuration data and calculate and transfer back to the

Note: The Valve capacity is carried over and used for the pipe loss calculations.

10 Transfer data back to the Area Sizing dialog.