Check valves are available in various types and specifications according to factors such as structural form, material and application. The following is a detailed summary of check valve types and specifications:
First, type
1. Classification by structure
Lift check valve: A check valve with a disc sliding along the vertical center line of the body. This valve can only be installed on the horizontal pipe, the fluid resistance coefficient is large. When the medium is along the flow, the valve disc is opened by the thrust of the medium. When the medium stops flowing, the valve disc falls on the seat by its own weight to prevent the medium from countercurrent. Lift check valve has two kinds of straight through and vertical, straight lift check valve medium inlet and outlet channel direction and seat channel direction perpendicular, and vertical lift check valve medium inlet and outlet channel direction and seat channel direction is the same, its flow resistance is smaller than straight through type.
Swing check valve: Check valve with disc shaped disc and rotating motion around the rotating shaft of the seat channel. Its resistance is generally less than the lifting check valve, suitable for larger caliber occasions. Swing check valves can also be divided into single valve, double valve and multi-valve according to the number of valves, the main purpose is to prevent the medium from stopping the flow or reverse flow, weakening the hydraulic impact.
Butterfly check valve: A check valve with a disc rotating around a pin in the seat. The disc check valve is simple in structure, can only be installed on the horizontal pipe, and has poor sealing.
Pipe check valve: A check valve with a disc sliding along the center line of the body. It is a newly emerged valve, small size, light weight, good processing technology, is one of the development directions of check valves.
Pressure check valve: This valve has the combined function of a lift check valve and a globe valve or Angle valve, and is usually used as a boiler feed water and steam cut-off valve.
Other types: Also include weight type check valve, bowl type check valve, brake disc check valve, ball type check valve, diaphragm type check valve.
2. Sort by material
Metal check valve: such as cast iron check valve, brass check valve, stainless steel check valve, carbon steel check valve, forged steel check valve, etc.
Non-metal check valve: such as plastic check valve, FRP check valve, etc.
3. Categorize by function
Silent check valve: such as DRVZ silent check valve, DRVG silent check valve, NRVR silent check valve, etc.
Special purpose check valve: such as SFCV rubber flap check valve, DDCV double flap check valve, etc.
Second, specifications
The specifications of the check valve are usually expressed by the nominal diameter (DN), and the common specifications are DN15, DN25, DN50, DN80, DN100, DN150, etc. In addition, there are specifications such as pressure levels, connection types (such as threaded, flanged, welded and clamp connections).
For example, the specification of the H12W internal thread spring check valve is DN15-100mm, and the pressure class is 1.6-32MPa; The specifications of H76H and H76W double-disc butterfly check valves are DN50-1200mm, and the pressure class is 1.6-10MPa.
Third, choose suggestions
When choosing a check valve, it is necessary to consider factors such as the specific piping system, medium characteristics, working pressure and temperature. Here are some options:
Select the appropriate check valve type and specification according to the flow direction and flow size of the medium.
Consider the corrosion of the medium, viscosity and temperature and other factors, choose the appropriate material.
Select a proper connection mode based on the installation space and maintenance requirements of the pipeline system.
Consult the manufacturer’s product catalog and technical specification sheet to ensure that the selected check valve meets the system requirements.
In short, there are a variety of types and specifications of check valves, and the selection should be comprehensively considered according to actual needs.
Post time: Oct-28-2024