Silent Check Valve

Technical Specifications

* PN10/PN16/Class 125LB/Class 150LB
* Size: 2″~12″ (DN50~300mm)
* Materials: Cast iron (GG25, ASTM A126 B), ductile iron (GGG50, GJS500, DIN1693, BS EN1563, ASTM A536 65-45-12)
* Working pressure: 10bar, 16bar, 200psi
* Applicable medium: Water, sewage, waste water
* Applicable temperature: -10℃~+80℃

Standard

* Design & manufacturing: BS5153, MSS SP-71
* Face to face: EN558-1
* Flanged ends: EN1092-2, ASME B16.1/B16.42, AS4087
* Inspection & testing: API598 / EN12266

1、 Infrastructure and Core Components

The core structure of a silent check valve consists of the following parts, which work together to achieve the dual functions of "silent" and "check":

Valve body: As an outer shell, it provides a medium circulation channel, and is mostly made of pressure resistant and corrosion-resistant materials such as cast iron and stainless steel.

Valve disc: multi disc type, composed of multiple small valve discs, hinged near the valve seat by a pin shaft, and can rotate around the axis. Diaphragm type, using an elastic diaphragm as the valve disc, controls opening and closing through deformation.

Buffer device: including springs, dampers, or elastic gaskets, used to slow down the closing speed of the valve disc and reduce impact force.

Shock absorption structure: The valve seat or disc edge is designed with flexible materials or curved shapes to reduce impact noise.

2、 Working principle during forward flow (open state)

When the medium flows in the forward direction:

Valve disc opening: Fluid pressure acts below the valve disc, generating upward thrust that overcomes the gravity of the valve disc, spring resistance, and friction of the sealing surface, causing the valve disc to rotate around the pin axis or the diaphragm to protrude upward, opening the channel.

Multi valve disc: Multiple small valve discs are dispersed and gradually opened to avoid water flow disturbance and noise caused by rapid impact of a single valve disc.

Low resistance flow: After the valve disc is opened, the channel cross-sectional area is large, the flow channel is smooth, the medium flow resistance is small, and the energy loss is low.

3、 Working principle during reverse flow (closing and silencing mechanism)

When the medium stops flowing or undergoes reverse reflux, the silent check valve achieves closure and noise reduction through the following mechanism:

Valve disc automatically closes:

Gravity effect: The valve disc falls due to its own gravity or the diaphragm resets due to the loss of positive pressure.

Spring assisted: The built-in spring provides additional closing force, accelerates valve disc reset, and ensures sealing reliability.

Reverse pressure drive: The reverse pressure generated by the reflux medium pushes the valve disc to fit against the valve seat.

Buffer and shock absorption process:

Multi stage closure: The valve disc first slowly falls due to gravity, and before contacting the valve seat, a buffer spring or damper intervenes to further slow down the speed and avoid the "bang" impact sound. The multi flap structure allows each valve flap to close in sequence, dispersing the impact force and reducing the peak noise.

Flexible sealing surface: The sealing surface between the valve disc and the valve seat is made of elastic materials such as rubber and EPDM. When in contact, it absorbs impact energy through elastic deformation, reducing the noise generated by rigid collisions.

Shock absorption structure design: A silencing chamber or guide groove is installed inside the valve body to guide the smooth flow of the reflux medium and reduce the noise generated by turbulence and eddies.

summarize

The working principle of a silent check valve is essentially to transform the traditional "rigid impact closure" of a check valve into a "flexible buffer closure" through structural innovation and material optimization, thereby significantly reducing noise and water hammer effects while preventing medium backflow.