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
Automated Diaphragm Valves
Metal Plastic Lined Diaphragm Valves
Flanged End Automated Ductile Iron Diaphragm Valves (PFA Lining)
Item # 1/2"/28-1-B/A
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Item # 1/2"/28-1-B/A, Flanged End Automated Ductile Iron Diaphragm Valves (PFA Lining)
— available in a wide variety of body materials, linings and end connections. By utilizing such highly resistant linings as Saran, Polypropylene, Kynar, Tefzel, Glass, Rubber, etc., virtually any chemical service within the pressure/temperature limits of the valve can be handled safely and economically.
No Stem Leakage
— since the diaphragm isolates the fluid stream there is no need for a packing gland — no atmospheric contamination, no leakage or waste, no expensive maintenance of stem, seats or stuffing box.
Bubble-Tight Shut Off
— results when the downward thrust of the stem and compressor assembly molds the flexible diaphragm against the weir. The diaphragm will accommodate itself to rust, scale, slurry, or fibrous material.
— with minimum pressure drop because of the absence of grooves, pockets or sharp changes in direction of flow.
— simple in-line maintenance. In less time than it takes to remove and replace a conventional valve, a new body diaphragm can be installed. Thus providing essentially a brand new valve at a tiny faction of the cost of a new or repaired conventional valve — all without removing the valve body from the line.
— the automated diaphragm valve provides an excellent means of handling the changing flow requirements in most process installations. By the addition of a positioner to the actuator, even more precise control can be achieved, especially in the handling of slurries, or viscous and fibrous materials.
— available in cast iron, ductile iron, carbon steel, stainless steel, Alloy-20, aluminum and bronze
Standard Actuator Features
-15 to 212
Acids and Alkalies
(1) Flanged Lined Ends
Valve Size [Fraction]
Valve Size [Decimal]
Diaphragm Control Valve Options
, Pilot Operated Controller Option
Line Pressure Conditions
100% P.D. means that downstream pressure falls to 0 psig.
0% P.D. means that downstream pressure remains at, or returns to essentially the same as the upstream pressure.
Diaphragm Material Description
- built like a tire - especially compounded materials - ruggedly reinforced with fabric plies and designed to take a great deal of physical abuse. The sealing bead provides a greater sealing ability by localizing closing forces for bubble-tight shut-off.
Standard Actuator Features
Actuator Size Number
, Actuator Size "0"
, Actuator Size "1"
, Actuator Size "2"
, Actuator Size "2A"
, Actuator Size "3"
, Actuator Size "4"
, Actuator Size "5"
Action of Actuator
(TYPE C) Air to Open - Air to Close
(TYPE H) Spring to Open - Air to Close
(TYPE HRT) Spring to Close - Air to Open
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.
Century Instrument Company
11865 Mayfield, Livonia, MI 48150
Phone: 734.427.0340 Fax: 734.427.5950
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