instruCalc

Flow Element Design, Selection & Analysis 

instruCalc features more than 70 routines associated with control valves, ISO flow elements, relief valves and rupture disks, and calculates process data at flow conditions for up to 64 fluids in either mixtures or single components. 

instruCalc calculates the sizes of control valves, flow elements and relief devices; produces data sheets for calculated items, and prepares instrument summaries and data sheets as a database for generating re-ports. 

instruCalc will calculate, display and print graphs of its calculations. Graphs available for Control Valves include: valve Cv versus flow; valve pressure drop versus flow;. Flow Element graphs include flow and differential values. 

instruCalc operates in both the US Customary System of Units or SI Units for both volumetric or mass flows 


Evaluate instruCalc

Download a fully-functional, time-limited licence. The download comprises alternative install files depending on your operating system and is compatible with Windows 7 and Windows 10 (both 32 bit and 64 bit).

InstruCalc

Capabilities

  • Calculates the sizes of control valves, flow elements and relief devices; produces data sheets for calculated items, prepares instrument summaries and data sheets as a database for generating reports.
  • Calculates, displays and prints graphs of its calculations. Graphs available for Control Valves include: valve Cv versus flow; valve pressure drop versus flow. Flow Element graphs include flow and differential values.
  • Operates in both the US Customary System of Units or SI Units for both volumetric or mass flows

Standards & Guidelines

  • Control Valve sizing to "ANSI/ISA-75.01.01-2002"dated 3 July 2002 which contains sizing for miniature valves.
  • Relief Valve sizing program to "API RP 520" 7th Edition January 2002 which includes two-phase flow sizing.
  • Tank venting to "API Std 2000" 5th Edition April 1998."
  • Restriction devices - ISO Venturi, ASME Long Radius Nozzle and concentric orifice plate (thick and thin) for gas and liquid services using Miller's Handbook, 3rd edition, 1996
  • Orifice Plate thickness based on the pressure and temperature of the selected plate material using Miller's Handbook, 3rd edition, 1996.
  • ISO orifice plate calculations have been updated to ISO 5167, 2003.

Control Valve Sizing

Three programs are available, each for standard and low flow valves:

  • Liquid Flow
  • Gas Flow
  • Two Phase Flow

Options for each valve calculation are:

  • Calculate Valve Size
  • Calculate Flow Rate
  • Calculate Valve Pressure Drop

Three cases are provided for each calculation:

  • Maximum flow
  • Normal flow
  • Minimum flow

Aids for the calculations are:

  • Typical valve data tables
  • Fluid properties at flowing conditions
  • A routine to calculate the valve pressure drop available in the piping system
 
InstruCalc Control Vavle  Gallery.jpg

After using normal flow to determine the valve size, scroll bars will change the flow, recalculate the data and determine the maximum and minimum flows that the piping system will allow.

The programs have a database of typical valves so that different valve data can be entered into the calculation in order to make the best selection. Try several and calculate until a valve style and size is selected which has the desired rangeability and does not have cavitation or noise problems. When a final selection is made the exact manufacturers' data can be entered for a final calculation.

Finally, for liquid valves in long piping systems, take the option for the minimum closing time, this is the water hammer program to determine if a special closing time is required to avoid water hammer.

 

Sizing Philosophy
Each manufacturer has its own formula for determining the valve size, the valve noise and the cavitation characteristics. instruCalc uses the ISA sizing formulas and the Masoneilan noise prediction method and incipient cavitation technique. The object of the program is to determine the valve size, the cavitation, flashing and noise problems and prepare a data sheet suitable for bid purposes. Some manufacturers may differ from these conclusions, usually the variations are minor and do not change the size and style. Occasionally the noise and cavitation characteristics will differ so that engineering judgment may be called for. The failure of a valve because of cavitation erosion can be extremely expensive. Sometimes a change in body style, or hardened trim is sufficient to eliminate the problem,


The typical valve data files are in ASCII format, three options are provided. They are Standard Valves, Low Flow Valves and a file for User Valves. They can be modified from within the program. The Standard file is based on Masoneilan data. The Low Flow file is based on Research Control Valves data. If another manufacturer is preferred edit the User valve file as required. If the manufacturer does not use the incipient cavitation factor (Kc) then leave the box empty. ISA S75 shows data for a typical file.

References

  • Control Valve Sizing Equations ANSI/ISA S75.01.01-2002
  • Masoneilan Noise Control Manual
  • ISA Handbook of Control Valves J. W. Hutchison

Flow Element Sizing

  • Calculate either orifice size, flow rate or differential range
  • Calculate vent or drain hole size if required
  • Calculate the minimum plate thickness
  • Calculate permanent pressure and power loss
  • Calculate accuracy percentage
  • Supply fluid properties at flow conditions
  • Supply steam data
  • Supply pipe sizes
  • Provide material selection
  • Use English or SI engineering units in any mixture
  • Use mass or volume flow units
  • Import process data
  • Print a calculation sheet using the Windows Print Manager
  • Prepare instrument data sheets:
    • WUSIWUG style
    • Initially, general sheets for bid purposes
    • Supply database of standard specification items
    • After vendor selection, revise for permanent records
    • Print a data sheet using the Windows Print Manager
  • Print a list of saved records:
    • Print all records
    • Print selected records
    • Print only records having required characteristics

Relief Valve Sizing

Familiarity with the ASME Section 8 and relevant API publications is recommended.

  • The Liquid Relief - known flow calculation has options to size for single or multiple valves or non-certified valves.
  • The Gas Relief - known flow calculation has options for Section 1, Section 8 or the Fire Code. The reaction force and the noise level are calculated.
  • The Steam Relief - known flow calculation has options for Section 1, Section 8 and the Fire Code and calculates the reaction force and noise level.
  • The 2-phase - known flow calculation has options for Section 1, Section 8 and the Fire Code and calculates the reaction force and noise level. It has 7 different 2-phase calculations.
  • The Heat Exchanger - entrapped liquid calculation is for a blocked-in liquid filled exchanger which has the heat turned on. It calculates the flow caused by the liquid expansion.
  • The Heat Exchanger - Tube failure calculation is for tube rupture where the tube pressure is 50% greater than the shell pressure. It assumes no vaporisation of the shell side product.
  • The Pipeline - Entrapped liquid calculation is for liquid expansion in long, blocked in, pipelines on a hot day. It usually only takes a very small relief valve to avoid blowing the gaskets.
  • The Fire size - Liquid vaporization is the most complex calculation. It gathers the flame wetted area of up to 15 liquid containing vessels. The heat input is calculated either by The API 520 or the National Fire Protection Association NFPA #30, method and a relieving flow rate is determined. The reaction force and relieving noise level are also calculated.
  • The Fire size - Gas expansion also gathers the flame wetted area, this time of up to 15 gas containing vessels. The maximum flow is then back calculated from the valve size. The reaction force and relieving noise level are then calculated.

Support

Accutech provides both engineering and key-stroke support for instruCalc backed up the publisher. The annually renewable Maintenance, Update and Support (SUM) agreement ensures that your licence is always up-to-date and that we can provide timely assistance.