What’s the Technological Design of Check Valve?

Check valve is a kind of valve whose opening and closing parts are round disc and whose action is generated by its own weight and medium pressure to block the backflow of medium. 

1. Introduction

Check valve is an automatic valve, also known as return valve or isolation valve. The valve disc movement mode is divided into lifting type and swing type. The check valve is often used as the bottom valve of the pumping device, which can prevent the return of water.

The sanitary check valve is made of imported SUS304 and 316L, which can meet the special requirements of various media in the field of food and biopharmaceutical. Its smooth, seamless, automatic emptying process fluid channel is also very suitable for the needs of steam and on-site cleaning. The inside and outside of the sanitary check valve body are treated by high-grade polishing equipment, which needs to meet the surface precision requirements. Its application range includes food, beverage, pharmaceutical, dairy products, beer and fine chemical industry. 

2. Process Design

(1) Quality Control of Main Body Semifinished Product

All parts of the valve are forgings, which are forged in strict accordance with the forging process specification and process card. The initial forging temperature, final forging temperature, deformation degree and deformation speed are strictly controlled, and the valve is cooled in accordance with the cooling method specified in the process specification. Chemical composition analysis, mechanical property test, intergranular corrosion test and metallographic structure analysis are carried out on the forged products, which all meet the corresponding standards after analysis, test and measurement. 

The quality of forgings is guaranteed by ultrasonic inspection and liquid penetrant inspection. The forgings is subject to 100% ultrasonic inspection and evaluation according to the requirements of RCC-M, and all surfaces of forgings is subject to liquid penetrant inspection and evaluation. 

(2) Welding

In order to improve the quality of overlay welding, the plasma argon arc welding technology is used to overlay the sealing surface of valve disc and valve seat. At the same time, in order to ensure the welding quality, the welding process used in the production was re evaluated. 

(3) Assembly Test

High quality products need not only high-precision parts, but also how to assemble these high-precision parts into high-performance products. In this process, technicians and senior technicians form an assembly and commissioning team, which is responsible for the assembly, commissioning and test of check valves. They also formulate the cleaning process and assembly process of spare parts. During the assembly and commissioning, the team strictly checks and strives for perfection to ensure the success of the assembly and commissioning of valves. They carry out all kinds of performance tests and make all indexes meet the requirements of the design specification.

(4) Process Inspection

Prepare quality plan for the check valve to ensure the quality control of the valve from raw materials, blank input, machining, welding, heat treatment, NDT, cleaning, assembly, factory test and various type tests.