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Siemens Industry 62VA

Constant Differential Relay

Order #: 62VA

Mfg Part #: 62VA

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Overview :

The Constant Differential Relay maintains a constant pressure drop across an internal needle valve for any flow setting up to about 2.1 cubic feet of air per hour. It thus provides a means for maintaining a practically constant volumetric rate of flow regardless of variations of the process or supply pressures. The differential maintained across the needle valve is 1 to 2 psig. This permits a greater opening of the needle valve, thus making it less subject to clogging. The constant differential relay may be used in conjunction with a rotameter type indicator.

The differential applied to the internal needle valve is determined by a spring-loaded diaphragm in the constant differential relay. This diaphragm controls the action of a valve plunger to automatically admit supply air to the needle valve at the required rate. A self-contained automatic bleed discharges excess supply air to the atmosphere when necessary. The constant differential relay is made of aluminum, brass, stainless steel, Neoprene and Buna-N. The rotameter is constructed of aluminum, stainless steel, borosilicate glass, Buna-N (O-rings), ruby sapphire (float) and brass (fittings). Neither will be affected by ordinary air line impurities.

Product Highlights

  • With Built-In Needle Valve
  • Attached Rotameter Piped Assembly
  • Supply Pressure:
    • Minimum: At least 5 psig greater than the maximum downstream pressure.
    • Maximum: 150 psig
  • Ambient Temperature Limits: -40° to +180°F (-40° to +82°C)
  • Purge Rates:
    • Maximum: 2.1 SCFH, 991 SCCM
    • Minimum: 0.9 SCFH, 425 SCCM