MDC Vacuum Products Corp.- Gate Valves

Gate Valves
Introduction

In the simplest of terms, vacuum gate valves are devices that regulate the flow of gases, fluids or materials through a structure or aperture by opening, closing or obstructing a port or passageway.

Gate valve assemblies consist of three key components: an actuator, a carriage/gate and a valve body. The actuator provides the power to position or transport the valve’s carriage/gate. The actuator is attached to the valve’s body via a rectangular bonnet flange. The gate closes or opens one of the valve’s body ports. The valve body is a vacuum tight chamber that is screwed, flanged or welded into a larger vacuum vessel or system.

It is worth noting that reliable vacuum valves were not commercially available until the late 1940s with the advent of O-ring elastomer seals. The elastomer O-ring was developed during WWII for use in aircraft hydraulic systems, and was soon thereafter adopted by the vacuum community as the standard means of making vacuum seals. Prior to this it was common practice, even in large research establishments, to upgrade general service valves for vacuum use by winding actuator shaft gaskets from string soaked in an Apiezon grease. MDC stainless steel vacuum gate valves incorporate patented C-Loc® and Uni-Loc™ gate valve locking mechanisms. No contact is made between a valve’s body and the locking mechanism, a feature which markedly decreases vibration and insures smooth valve operation.

MDC gate valves require about half the number of moving parts found in comparable competitor valves. This reduction in moving components minimizes wear and particulate generation which in turn provides valves of superior performance and reliability. The valves’ low outgassing characteristics can be attributed to a fusion welded 300 series stainless steel body, welded AM-350 stainless steel nesting bellows as well as small cross-section O-rings and the elimination of blind internal cavities. MDC circular gate valves are offered in various sizes ranging from .625" to 12" port diameters. Standard port mounts include: Del-Seal™ CF metal seal flanges, which are recommended for ultrahigh vacuum service; ISO Kwik-Flange™ and ISO Large-Flange™ fast make and break elastomer sealed flanges, ideal for high vacuum applications requiring frequent assembly and disassembly; and ANSI ASA elastomer seal port flanges for use in high vacuum applications where ANSI standards are specified.

Gate valve actuation is available in both manual and electropneumatic configurations. Custom designed valves are available on request.

Standard Features