History of Diaphragm Valves
Valvulas Century De S.A. de C.V.
Automatic Diaphragm Valves
Manual Diaphragm Valves
Spare Parts for Diaphragm Valves
Diaphragm Relief Valves
Diaphragm Control Valves
Process Control Valves and Instrumentation Products
Spare Parts for Automated and Manual Diaphragm Valves
Air to Open - Spring to Close Type "HRT" Spare Parts
Item # item-3865
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Item # item-3865, Diaphragm
Action of Actuator
Spring Case Dimensions - versus - Line Pressure - HRT Actuators
The choice of actuator size is determined by the line pressure through the value and the available operating air pressure. Some operating conditions call for substantial line pressure downstream when the valve closes.
After the valve closes, if the downstream pressure is less that 30 % of the upstream pressure - this condition is 100% Δ P. If the downstream pressure is 30% or more of the upstream pressure - the condition is 0% Δ P.
Actuator housing, bonnets and spring cases are made from ASTM 159-70, a high grade pressure type cast iron with 30,000 pounds per square inch tensile strength. Actuator diaphragms are specialty reinforced with Nylon and are constructed to offer resistance to ballooning and other forms of deformation. As a result, substantially higher operating air pressures can be used to achieve valve closure than is permissible with competitive actuators of aluminum or pressed steel.
This higher air pressure capability, together with the unusually long stroke of Century actuators, makes it possible to use smaller actuators with a significant saving in both cost and space without short-stroking the valves.
To facilitate parts inventory and to lower maintenance costs, most components such as actuator diaphragms, seal assemblies, push-rods, etc., are interchangeable between the three modes of actuators, viz., spring open, spring closed and air to air.
To meet any present or future OSHA requirements, the powerful springs in the spring-closed actuator can be fully relaxed prior to dismantling for service. This exclusive feature prevents the spring case housing from becoming a deadly projectile during dismantling for service.
The totally enclosed and epoxy coated non-aluminum construction provides complete protection against the effects of caustic atmospheres and cleaning solutions.
A valve position indicator is included as standard equipment on all Century actuators to show the position of the valve in its stroke.
A complete and detailed record is on file at the factory on every valve manufactured during the years since 1950. Keyed to the serial number which appears on the data plate attached to the valve bonnet, this file provides a means of speedily obtaining any information required on every valve we have produced.
Century Instrument Company
11865 Mayfield, Livonia, MI 48150
Phone: 734.427.0340 Fax: 734.427.5950
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