Conductance Control Butterfly Valves (ASA flanged)

Conductance Control Valves

Conductance control valves open and close to obstruct a stream of gas, maintaining a specified chamber pressure by enabling a steady flow into the chamber. Unlike other valves, which seal off gas chambers, conductance control valves usually do not make an airtight seal.

When operated with its appropriate control and with a capacitance manometer to sense chamber pressure, each butterfly valve conductance controller opens and closes to limit gas throughput according to the settings of the control. This triad of components conductance control valve, conductance controller, and the capacitance manometer) makes a closed-loop which, if operated properly, can regulate the pressure of any chamber. Butterfly conductance control valves have a greater range of conductance, between fully open and fully closed, than other conductance controller designs.

Butterfly Conductance Control Valves

All butterfly structured conductance control valves have similar mechanical design, but differ in motorization. Our most popular model is the MKS253. The butterfly valve type controller has a wide ratio of conductance between fully open and fully closed. In general, it also offers smaller bore sizes than those available in vane controllers. Because it suits tube diameters used in forelines, it can be applied to processes with base pressures within reach of mechanical pumps that have high process pressures (e.g., crystal pulling).

Kurt J. Lesker offers most flange sizes with or without an o-ring on the flapper. With the o-ring, the conductance controller can offer a lower controllable conductance, but not as a regular butterfly shutoff valve. Any "set" in the o-ring that slowly relaxes when the valve first opens will alter the conductance orifice. But since an electronic control actuates the conductance controller while monitoring the pressure transducer feedback, it automatically compensates for the changing orifice.

Features

• Motorized
• Constructed of 316 stainless steel.
• "Wetted" materials are stainless steel, fluorocarbon, and (for models with o-ring sealed flappers) Teflon^®
• Models featuring an o-ring sealed flapper can lower controllable conductances

NOTE:

• The control valve does not come with the controller or cables. These must be ordered separately. Models without the o-ring sealed flapper are not recommended to be used as shutoff valves.
• The "standards" for ASA flanges are not exactly standard. We urge anyone planning to use an ASA flanged conductance controller to check the flange sealing O-ring dimensions listed. Determine that the Oring's ID is greater than the ID of the flange to which the conductance controller will mate.

Lesker Conductance Control Butterfly Valves (ASA flanged)