Valves and Valve Equipment

ARI-CHECKO-V/D Inline Check Valve: Working Principle, Features and Applications

Learn how ARI Armaturen CHECKO-V flanged piston check valves and CHECKO-D wafer disc check valves work, their material options and typical applications.

ORFA Technical TeamUpdated: Oct 30, 20263 min read

Keeping media moving in the right direction and preventing backflow is critical for safety and efficiency in industrial piping. Backflow can damage pumps and heat exchangers and cause unwanted mixing and contamination. The ARI-CHECKO-V/D check valve series is installed directly in the pipeline to ensure flow in one direction only. ORFA supplies these check valves from the German manufacturer ARI Armaturen to industrial plants.

This article covers the differences between ARI-CHECKO-V and ARI-CHECKO-D, their working principle, advantages, specifications and applications.

What Are ARI-CHECKO-V and ARI-CHECKO-D?

Both are inline check valves that open when flow is in the correct direction and close automatically when flow stops or reverses. The main difference lies in the body and closing element design:

Model	Design	Key feature
ARI-CHECKO-V	Flanged body, piston (lift) type check valve	Robust body suited to higher pressure and temperature duties
ARI-CHECKO-D	Wafer type disc check valve installed between two flanges	Very short face-to-face length, light and compact

Working Principle

Forward flow: The pressure of the medium pushes the closing element (piston or disc) open against the spring force.
Open position: As long as flow continues, the closing element stays open and the medium passes.
Flow stops: When flow decreases or stops, the spring pushes the closing element towards its seat, so the valve starts closing before reverse flow develops.
Closed position: Pressure from the reverse direction presses the closing element onto its seat, improving tightness and preventing backflow.

Spring-assisted closing shuts the valve before reverse flow can gain speed, which helps reduce the risk of water hammer.

Advantages

Reliable backflow protection: Protects pumps, heat exchangers and other equipment from damage caused by reverse flow.
Wide range of applications: Used in many sectors, from heating systems and power generation to chemicals and petrochemicals.
Material options: Different body materials can be selected according to medium, temperature and pressure.
Easy installation: Mounted directly in the pipeline; the wafer type CHECKO-D takes up very little space.
Low maintenance: The simple design keeps maintenance requirements low.

Specifications

Feature	Options (depending on series)
Body material	Cast iron, ductile iron, cast steel, stainless steel
Internals	Stainless steel, bronze
Connection	Flanged, wafer, butt-weld ends
Nominal size	CHECKO-D: DN15–DN100 as standard (up to DN350 on request); CHECKO-V: up to DN500 depending on model
Pressure rating	CHECKO-V: PN6, PN16, PN25, PN40 depending on material and size; CHECKO-D: PN40
Maximum temperature	Approximately 300 °C to 450 °C depending on body material for metal-seated versions; for soft-seated versions limited by the seat material (e.g. EPDM 120 °C, FPM 150 °C)
Opening pressure	Depends on spring type and model

Pressure and temperature limits vary with model, size and material combination; please check the technical data of the specific product before selecting.

Tip: Installing a check valve too close to a pump discharge or directly after elbows, valves and other sources of turbulence can cause the closing element to flutter and wear prematurely. Where possible, leave a straight pipe run upstream of the check valve.

Applications

Heating systems (especially preventing backflow in heat exchangers)
Power generation plants
Refineries
Petrochemical plants
Chemical industry
Food and beverage industry
Water treatment plants

Frequently Asked Questions

What is the difference between ARI-CHECKO-V and ARI-CHECKO-D?

CHECKO-V is a piston-type check valve with a flanged body. CHECKO-D is a wafer type disc check valve installed between two flanges, with a very short face-to-face length that is ideal for tight spaces.

Why does a spring-loaded check valve reduce water hammer?

The spring pushes the closing element towards its seat as soon as flow starts to stop. Because the valve closes before reverse flow gains speed, the pressure surge caused by sudden closure is reduced.

Which body material should I choose?

It depends on the medium, operating pressure and temperature. Cast steel is preferred for high temperatures and pressures, stainless steel for corrosive media. Our technical team can help with the final selection.

Conclusion

ARI-CHECKO-V/D inline check valves are reliable products that protect equipment and ensure safe operation by preventing backflow in industrial pipelines. Choosing the right model, material and pressure rating increases system efficiency and reduces the risk of failure. For other check valve types, explore our check valves product group.

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