Control Valve Test Stand                home


DESCRIPTION

An Industrial OEM Controls Manufacturer required a fully automated End-of-Line Flow Test Bench to calibrate and verify the operation of an electronically compensated fuel flow control valve. This valve is used to precisely control the flow rate of fuel to reciprocating gas engines. The test system would be required to automatically manage the calibration and test sequence, requiring minimal intervention by the test operator.


SYSTEM REQUIREMENTS

»  Flow Technology - Critical Flow Venturi (Sonic Nozzle) Based System.
»  Wide Service Range - Extended Flow Range with high accuracy and repeatability.
»  Multiple Communication Interfaces - To both the UUT and the Flow Stand.
»  Automated Data Management - For both Test Configuration Input and Test Results to a corporate database.
»  Data Acquisition - Interfacing and Communication with a customer-supplied DAQ system.
»  Automated Testing Capability - Utilizing an off-the-shelf TEST EXECUTIVE.
SOLUTION

FLOW SYSTEMS designed and manufactured an Air Flow Metering Test System that employed a binary set of ten (10) Sonic Nozzles (Critical Flow Venturis). The two largest Sonic Nozzles are housed in piping runs that conform to ASME specifications. The smaller nozzles are housed in multiple nozzle manifolds, designed and manufactured by FLOW SYSTEMS, Inc. The piping runs incorporate a pressure averaging piezometer ring with four (4) pressure taps and a temperature tap, while the Sonic Nozzle Manifolds contain multiple inlet pressure taps for pressure averaging.

The flow stand is composed of two separate carbon steel frameworks. One framework contains the Sonic Nozzle flow elements, while the second stand contains the shop air supply regulating valves and interface connections to the customer's facility compressor pressurized header.

The test stand consists of several integrated sub-systems that serve to monitor and calibrate the product. The air handling sub-system is used to supply, regulate, and measure the flow rate of the test fluid (air) through the product. Various transducers are used to make the measurements required to calibrate and verify the operation of the Unit-Under-Test. The computer/data acquisition system is used to display the instrument readings and to store data from the calibration and test parameters. The computer system also provides a continuous visual display of the system operation for validation and troubleshooting purposes. The database management portion of the system manages the handling of various records and files which the product requires, or which are generated from the calibration/test sequence.

The as-built test system was a joint effort between the OEM manufacturer and FLOW SYSTEMS. FLOW SYSTEMS designed and built the airflow test stand and developed a PC-base controller that incorporates the necessary UUT communication and automated test sequencing. The OEM manufacturer implemented a hardware/software solution for controlling the airflow test stand. This necessitated that the two controllers interface properly allowing for bi-directional communication.

 
SPECIFICATIONS

» Flow Elements: Ten (10) torodial throat design Sonic Nozzles with a binary progression of throat area.
» Flow Element Calibration: ±0.35% of indicated discharge coefficient (traceability to NIST).
» Flow Element Inlet Pressure Calibration Range: 30 to 130 psia.
» Flow Range: 7.5 to in excess of 15,000 lbm/hr of dry air.
» Flow Stand Accuracy: Estimated at better than ±0.42% of reading.
» Repeatability: 70 psi Estimated at better than ±0.1% (defined as two (2) times the standard deviation divided by the mean of thirty (30) identical samples).

 

 

SYSTEM LAYOUT

The following illustration shows the physical layout of the test system.

 

SYSTEM SCHEMATICS 

The following illustration shows the Pneumatic and Instrumentation (P&ID) layout of the test system.

Click to view enlarged image

 

SOFTWARE OPERATOR INTERFACE 

The following image illustrates the operator interface of the test system.

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