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 basic 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.

Advantages of this design include:
MINIMUM NOISE -- The flow path through the WELKER JET Control Valve is a streamlined, high recovery design (see graph). 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.

WELKER JET Control Valves are available either as Flanged. Insert, or Top Entry Styles. Applications include flow control and pressure control. WELKER JET Control Valves may also be used in monitor regulator applications.