281.491.2331 13839 West Bellfort Street Sugar Land, TX
281.491.2331 13839 West Bellfort Street Sugar Land, TX
ISO 9001:2015
U.S. Patents
80 + U.S. Patents
Since 1954
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Welker Jet

In 1958, R.H. Welker designed the first rubber plug type control valve to meet the demands of the gas industry for a quiet, versatile control valve. The many refinements and improvements made since that time have been incorporated into the current line of Welker Jet® Control Valves.

The proven design consists of a rubber plug which is expanded by a hydraulically operated piston and cylinder system. As the hydraulic force on the plug increases, it expands radially until it seals against the inside of a fixed liner. Hydraulic pressure is provided by a pneumatically operated diaphragm motor.

ApplicationsFlow Control, Pressure Control

Unmatched Design

This streamlined, aerodynamic design generates a unique flow path that is unmatched by any other control valve on the market today. 

Welker Jet Design
Why Welker?


Minimum Noise

The flow path through the Welker Jet®  Control Valve is a streamlined, high recovery design. Turbulence is greatly reduced, allowing a noise reduction of 10 to 30 dbA over other types of control valves.

Quick Response

The hydraulic linkage between the diaphragm motor and control valve allows instant response to instrument pressure changes. The virtually frictionless hydraulic system eliminates the need for a positioner.

Positive Shut-Off

The large, flexible sealing area will achieve a positive bubble tight shut-off, even around weld slag and other large particles.

Infinite Rangeability

Precise regulation is possible over 100% of the control valve’s range, from full flow down to no flow. The 8-inch Welker Jet® Control Valve is as accurate at low flow conditions as the 1-inch model. This control valve cannot be oversized.

Simplified Maintenance

The Top Entry Welker Jet® Control Valve is designed so that routine maintenance can be performed without opening the hydraulic system or removing the body from the line.

Master System


Standard instrumentation consists of a filter dryer, first and second stage regulation with appropriate relief valve, and a pneumatic controller. The pressure sense line should be mounted as far downstream as possible.

An amplifying relay is used when the pressure requirements for positive shut off exceed the controller output or when greater response time is required. The amplifying relay is mounted between the controller output and the diaphragm motor.

A pilot operator is used for pressure control. Sensor line should be mounted as far downstream as possible. Filtered and regulated supply should be used to operate pilot.

I/P operation is used for flow or pressure control. a 4-20 mA of 1-5 V signal from the flow computer operates the control valve.