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Diaphragm Valve & Stager Control > K53 Series

Product Information


Why new valves? AquaMatic, Inc. was the innovator of low cost plastic diaphragm valves for the water treatment and fluid handling industries. This new generation of GE Osmonics AquaMatic plastic diaphragm valve is designed to meet today's requirements and permit us to better serve today's market needs. GE Osmonics is committed to continuing to serve this market with new, improved products.

These valves are ideal for clean and wastewater handling and treatment systems. Specific applications include deionizers, filters, softeners and reverse osmosis pretreatment.

Sizes offered range from 1 inch (25mm) through 3 inch (76mm). Maximum working pressure, non-surge, is 125 psi (8.6 bar) with maximum temperature of 140F (60C). A new fail safe closed option is available in all sizes. Larger flow paths and a Cv significantly higher than our 520 Series are featured, thanks to the high lift disc.

What is NEW?

  • TRUE UNION END CONNECTIONS - Female socket end connections on all valve sizes in US, metric and JIS standards PVC pipe.
  • DOUBLE SHAFT SEAL with a vent between the seals virtually eliminates the possibility of leak between flow and control chambers.
  • NEW SIZES including full 2-inch and 3-inch valves.
  • HIGH FLOW CAPABILITY - High lift disc provides improved flow with much higher Cv than the 520 Series.
  • NEW LIMIT STOP/POSITION INDICATOR - Optional combination limit stop and position indicator is available.
  • MOUNTING PADS - Valve can be supported independently in the manifold.
  • NO EXPOSED METAL PARTS - Internal or external.
  • NEW FAIL-SAFE CLOSED OPTION -Full flow with 30#, 60# or 100# springs in all sizes up through 3 inches.

NEW CONSTRUCTION - Noncorrosive glass-filled engineering thermoplastic provides superior body strength and and attractive look.

Features of the K53 Series

NO METAL TO RUST - There are no exposed metal parts-internal or external. The line fluid never touches metal. Corrosion resistant plastic body.

EASY TO SERVICE - New cap seal uses no nuts and bolts. Retaining ring allows quick, easy servicing.

EASY INSTALLATION - True union end connections clamped to the body with a retaining nut and positive O-ring seal make installation quick and simple.

DUAL SHAFT SEAL - The new design incorporates two O-ring seals between the shaft and shaft guide and also between the shaft guide and the body with a vented space between. Should a leak occur due to wear or damage, the leaking fluid will pass to the vent where it can be detected. There is virtually no possibility of cross contamination of line fluid and control media.

UNION END CONNECTIONS - The connector is clamped to the body by a glass-filled engineering thermoplastic retaining nut. An O-ring mounted in the body recess seals against the flat, smooth face of the end connector providing a tight closure.

COMBINED POSITION INDICATOR/LIMIT STOP - Flow can be continuously adjusted from full on to full off while an indicator shaft shows the position of the valve.

NEW CAP SEAL DESIGN - The diaphragm and cap are held in place by a large retaining collar. There are no metal nuts and bolts to corrode in aggressive atmospheres. Since the cap may be easily removed, it is easy to service the valve. As in all AquaMatic diaphragm valves, this may be done without removing valve from piping.

MOUNTING PADS - Mounting pads at the base of the valve allow the valve to be independently supported in the manifold.

The Series K53 plastic diaphragm valves are designed for controlling the flow of liquids. Positive control action is achieved by applying a control pressure, equal to line pressure, to the upper or lower diaphragm chamber. This control pressure may either be water or clean, oil-free air. The valves are constructed of corrosion-resistant composite material and designed so that the line fluid never contacts a metal surface. Therefore, the valves are ideal for handling water (including pure or deionized water), salt solutions and many corrosive liquids including most acids and caustics. This broad range of compatibility makes the valves well suited for use on clean water and wastewater handling and treatment systems. Specific applications are deionizers, filters, softeners, and reverse osmosis water pretreatment systems.

The Series K53 plastic diaphragm valves retain all the important features of the AquaMatic's diaphragm valves including:

  • Low Pressure Loss - The Y pattern permits higher flow than comparable valves. The K53 Series valves are designed with higher lift discs, providing larger flow paths and a Cv significantly higher than our Series 520 valves.
  • Positive Control - Separate flow and control chambers permit positive closing without springs. Optional low cost springs are available to assist opening or closing on low pressure or self-draining applications.
  • Cost Effective - Both low initial cost and low lifetime maintenance cost.
  • Durable - The Series K53 valves are designed rugged for an average maintenance free life of three to five years and longer dependent upon cycle rate and environment.
  • Ease of Maintenance - Routine inspection or preventive maintenance may be accomplished without removing the valve body from the line. The cap of the K53 valve can be removed by unthreading a single retaining collar.

We continue to offer familiar options for the Series K53 valves including spring assist open, spring assist close and flow control limit stop. A new option is a combined position indicator and limit stop. Another enhancement is that the spring used for the spring assist open option is the same spring which is used for the spring assist closed option. Externally normally closed option is also available.

The valve is made of strong, long-wearing components. The valve body and cap are made from 30% glass filled composite material. The diaphragm is Buna N on nylon and standard seals are EP (ethylene/propylene). The use of these valves to control chemical solutions, such as acids and caustics, may require the use of optional seals and/or other internal components. It should also be noted that these valves are not compatible with aromatic hydrocarbons. Control fluid for position indicator and limit stop options should either be air or neutral pH water.


Working Pressure- 125 psi (8.6 bar) Maximum, Non-surge; 20 psi (1.4 bar) minimum (without springs).
Temperature- 140F (60C) Maximum, 180F (82C) Optional.

Fail-Safe Closed Valves

Full flow spring closed valves are available in sizes 3/4 inch (19 mm), 1 inch (25 mm), 1-1/2 inch (38 mm), 2 inch (51 mm), and 3 inch (76 mm). Valves may be equipped with a combination of springs which hold the valve closed against 30 psi (2.1 bar), 60 psi (4.1 bar), or 100 psi (6.9 bar) line pressure. Valves will start to open when line pressure is no more than 15% more than the spring rating.

The springs are completely enclosed in an aluminum cap. The springs and the cap have a special corrosion-resistant finish.

The spring closed valve is able to be serviced safely with no special tools. The force of the springs can be completely unloaded or loaded while the springs are retained in the cap. Therefore the cap, which is in the spring housing assembly, is a self-contained unit which can be easily and safely removed for valve servicing. Springs are available only in preassembled kits.

The design of this fail-safe spring closed valve allows for a full stroke and therefore, full flow. The Cv is the same as the standard series valves. See Flow Capabilities section for full flow data.

Standard seals are ethylene propylene by fluorocarbon elastomers or Butyl seals are also available. End connections are PVC female socket in ASTM, ISO or JIS. CPVC end connectors are also available. Limit stop option not available on fail safe closed valves.


Working pressure- 125 psi (8.6 bar) maximum, non-surge
Temperature- 140F (60C) maximum, 180F (82C) optional
Control pressure- 75 psi (5.2 bar) is required to open a 100 psi (6.9 bar) spring closed valve.

See Dimensions section for dimensions. See Flow Capabilities section for flow data.

Dimensions For K53 and K56 Valves

Dimensions (Approximate) - inch (mm)

Size - inch (mm)


Cv (1)

Valve - .

Fail Safe

A (2)







0.75, 1.0
(19), (25)
















































(1) Cv is the flow rate in gallons per minute of water at 60F at 1 pound pressure drop or (flow rate in cubic meters per hour of water at (15.5C) at 1 bar pressure drop.)
(2) The "A" dimension is the distance between face to face seal surfaces.
(3) V560 bodies are available with threaded or spigot ends.

Flow Capabilities of AquaMatic Plastic Diaphragm Valves

For all K53 models including fail-safe and spring closed models.

Typical Applications

Consult your local GE Osmonics sales representative for assistance with your specific control requirement. AquaMatic diaphragm valves are ideally suited to meet any on/off fluid control requirement within the operating specifications of the valve. Some typical applications are:

  • Concrete (Chemical) Additives
  • Agricultural Irrigation
  • Turf Irrigation
  • Desalinization
  • Distillation
  • Evaporation
  • Metal Recovery Systems
  • Pump Controls
  • Fluid Handling
  • Process Water Systems
  • Mining Wastes
  • Cooling Tower
  • Level Control Systems
  • Heating
  • Air Conditioning
  • Plastic Molding Machinery
  • Herbicide, Pesticide, and Fertilizer Spray Equipment
  • Electronics Industry (Process, Cleaning)
  • Laundries
  • Car Washing Systems
  • Nitrogen Handling
  • Ammonia Handling
  • Solar Systems
  • Bleach Handling
  • Detergent Handling
  • Solvent and Chemical Handling Systems
  • Swimming Pools

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