NAFCO | What Is a Brass Check Valve

NAFCO | What Is a Brass Check Valve
Time:2017-10-23 From: NAFCO-China Brass Ball Valves and Brass Fittings Manufacturer

Brass Check Valve Definition

Brass Check Valves, also called non-return valve or one-way valve,  is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. There're brass spring check valve, brass foot valve, swing type check valve.  Brass strainer valve is installed in pipeline to filter impurities of the flow,  normally Y shape type, the flow was cleaned the by a stainless steel screen / filter inside of the valve when it goes through. It is widely used in residential premises and for industrial or commercial applications


Brass Check Valve Classification
Brass check valve can be divided into lift type check valve, swivel type, butterfly type, pipe type, slow closing type and diaphragm type check valve according to its structure.

1. Swing Check Valve
The check valve can be mounted on a horizontal pipe along the vertical centerline of the valve body. The ball valve can be used on a high pressure small diameter check valve. The shape of the valve body of the lift check valve is the same as that of the shut-off valve (which can be used with the globe valve), so its fluid resistance coefficient is large. The upper part of the valve flap and the lower part of the bonnet are machined with guide sleeve, and the valve guide can be freely lifted in the valve guide. When the medium flows downstream, the valve flap is opened by the medium thrust. When the medium stops, hanging down on the seat, from the media to prevent countercurrent effect.

Brass Swing Check Valves

Brass Swing Check Valves from NAFCO Valves

2. Swing check valve
The flap of the swivel check valve is disc-shaped and rotates around the shaft of the valve seat. The flow path is smaller than the lift-type check valve and is suitable for low flow rate and flow. Often change the large diameter of the occasion, but not for pulsating flow, the sealing performance of less than lift. Swivel check valve is divided into single, double and multi-type three, these three forms mainly by the valve caliber to the purpose, in order to prevent the media to stop the flow or back flow, weaken the hydraulic shock.
China Brass Spring Check Valves

Brass Spring Check Valves from NAFCO Valves

3. Disc check valve
Brass spring check valves is a kind of check valves that rotates around a pin within a seat. Disc-type check valve structure is simple, can only be installed in the horizontal pipe, the seal is poor. The butterfly check valve is similar in structure to butterfly valves. Its structure is simple, flow resistance is small, and water hammer pressure is also small.

Brass Spring Check Valves with filter from NAFCO Valves

Brass Spring Check Valve with stainless filter from NAFCO Valves

4, the pipeline check valve
Pipeline check valve is a new type of valve, its small size, light weight, processing technology is good, is one of the direction of development of the check valve. But the fluid resistance coefficient is slightly larger than the swivel check valve.

Brass Foot Check Valves

5, pressure check valve
This valve is used as boiler feed water and steam cut off the valve, it has a lift check valve and cut valve or angle valve integrated function.

6, Diaphragm check valve
Diaphragm check valve has a variety of structural forms, China brass ball valves, are used as the opening and closing diaphragm, because of its good water hammer, simple structure, low cost, in recent years, rapid development. However, the use of diaphragm checks valve temperature and pressure by the diaphragm material restrictions.

Applications of brass check valves:

The purpose of using the check valve is to prevent the media backflow, generally in the pump outlet are equipped with a check valve, and also in the compressor outlet to install the check valve, in short, in order to prevent the media back, in the equipment, Are the check valves installed. Check valve is generally used for cleaning the flow medium, should not be used for solid particles and viscous fluid medium, or check valve open is not sensitive, close the seal is not reliable, and the fluid back is not reliable enough. Check valve is an automatic valve, its main role is to prevent the media back to prevent the pump and drive motor reversal, and container media discharge. The check valve can also be used on piping where the pressure may rise above the supply system that exceeds the system pressure. Usually the valve is automatically working, in a direction of the flow of fluid under pressure, the valve flap open; fluid flow in the opposite direction, by the fluid pressure and the valve flap from the valve seat in the valve seat, thus cutting the flow. Selection of different materials, check valves can be applied to water, steam, oil, nitric acid, acetic acid, oxidizing media, urea and other media.

The difference between Brass Check Valves and other brass valves

There are some other brass valves in China brass ball valves, brass radiator valves, brass gate valves, brass angle valves..That have different mechanism and functions compared to brass check valves, they are also important devices for pipelines.

Principles to select brass check valves:
1, for DN50 following high and medium pressure check valve, should use vertical lift check valve and straight-through lift check valve.
2, for DN50 below the low pressure check valve, should use butterfly check valve, vertical lift check valve and diaphragm check valve
3, for DN> 50, <600 high and medium pressure check valve, should use the swivel check valve
4, for DN> 200, <1200 in the low pressure check valve, should use non-wear spherical check valve
5, for DN> 50, <2000 low pressure check valve, should use butterfly check valve and diaphragm check valve
6, for the requirements of the closure of the impact of small water shock or no impact on the pipeline, should use slow closed swing and slow closed butterfly check valve
7, for the pump inlet pipe, should use the bottom valve
8, check valve is generally suitable for clean media, should not be used for containing solid particles and viscosity of the larger media. Diaphragm check valve for easy to produce water on the pipeline, the diaphragm can be a good elimination of the media when the water against the water, but by the temperature and pressure constraints, the general use of low-pressure room temperature pipe.

Common Problems and solutions of Brass Check Valves
When the center of the valve is not perpendicular to the horizontal plane, the valve flap is not flexible, which affects the valve opening or closing and is not reliable. In this case, the check valve should be re-installed So that it is in a normal working position. Check valve installation should pay attention to the flow of fluid, so that the valve in the reverse flow of fluid can automatically shut down. Check valve sealing surface damage will cause the valve inside the leakage, the emergence of part of the fluid reflux, China brass ball valves should be based on the degree of damage to the sealing surface processing or replacement of the seal, and then with the valve grinding with the valve can also refer to the common fault and maintenance to exclude.

Common problems are:
① flap broken;
② medium back flow.
Causing the disc to break the reason is the check valve before and after the media pressure is close to the balance and mutual "see the" state of the valve flap often with the valve seat, some brittle materials (such as cast iron, brass, etc.) made of the valve It was broken. The precautionary approach is to use a check valve that is a ductile material.
Media back to the reasons for ① seal surface damage; ② sandwiched impurities.
Repair the sealing surface and clean the impurities, you can prevent backflow.

In case of futher questions, please feel free to contact NAFCO, or send emails to




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