Marine Dual Plate Check Valve is a type of automatic valve specifically designed for use in ship piping systems to prevent the backflow of media.

Key Features:

Ultra-short structure, space-saving: Utilizing a wafer-type connection, its structural length is only about 1/4 that of a traditional flange check valve, making it ideal for applications with strict space constraints, such as ships and high-rise buildings.

Quick closure, effective water hammer resistance: The valve disc closes quickly and automatically under spring force, with a short closing stroke, effectively reducing water hammer impact caused by backflow and protecting the pipeline system.

Flexible installation, wide applicability: Can be installed horizontally or vertically on pipelines; simply ensure the medium flow direction aligns with the arrow direction on the valve body, greatly improving installation convenience.

Reliable sealing, stable performance: Through a dual-disc design and reliable sealing structure, complete sealing is achieved, reaching zero leakage in pressure tests.

Installation Precautions:

Installation Direction: This valve can be installed on both horizontal and vertical pipelines. However, please note the following:

When installed vertically, the medium flow direction must be from bottom to top for the valve disc to properly return to its closed position under gravity and spring force.

When installed horizontally, avoid placing the valve stem in a vertical position to prevent impurities from accumulating at the bottom and affecting the seal. Experienced installers recommend ensuring the valve stem (the shaft connecting the two valve discs) is horizontal during horizontal installation.

Never install the valve on a vertical pipeline where the medium flows downwards, as this will cause seal failure.

Valve Body Marking: The valve body usually has a clear flow direction arrow cast on it; it must be aligned with the pipeline medium flow direction during installation.

Main Reference Types

H76: It features a short structural length, small size, and light weight; its structural length is only 1/4 to 1/8 of that of a traditional flange check valve, and its weight is 1/4 to 1/20. The fully rubber-lined models feature a complete rubber lining covering the valve body cavity and butterfly plate surface, making them suitable for corrosive media. The rubber lining protects metal components from corrosion. The H76 series check valves offer advantages such as low flow resistance, reliable sealing, rapid closure, and low water hammer pressure.

Here's the pictuere for fully rubber-lined dual plate check valve:

H77: Often referred to as the "short structure" or "DIN" series, the structure has a more compact length.

Although both H76 and H77 can effectively reduce water hammer impact by relying on spring assistance when closed, and both can be installed on horizontal or vertical pipes, it is necessary to specify the exact dimensions of the installation space when selecting and purchasing them, and to confirm whether the shorter H77 or the more versatile H76 is needed.

H46: This is a flanged type valve, where the valve body has its own flange and is directly bolted to the pipe flange. Its advantages include a more robust connection, higher pressure resistance, and easier maintenance, but it is also longer and heavier.

Type	Main Structure Features	Structure Length	Typical Application	Reference Picture
CB/T 4303-2013	Wafer Type, Maine Standard	Standard	Ship piping system
H76	Wafer-type, General type	General pattern	Industrial and construction water supply and drainage
H77	Wafer-type, Short-pattern	short-pattern	Installations with limited space
H46	Flange Type, Low-resistance, slow-closing	Standard	Pump outlet (waterproof flapper)