Diaphragm compressor construction and working

The main parts of Keepwin diaphragm compressor are organism, cylinder, piston assembly, diaphragm assembly, crankshaft, connecting rod, crosshead, bearing, packing, air valve, etc.

Body

The body of diaphragm compressor is the basic component of compressor positioning, which is generally composed of body, middle body and crankcase (frame). Each motion damper is installed inside the machine body, and is used for positioning and guiding the transmission parts. Lubrication in crankcase

Oil, external connection cylinder, motor and other devices. During operation, the engine body shall bear the force of piston and gas and the inertia force of moving parts, and transfer its own weight and all or part of the weight of compressor to the foundation.

 Cylinder

Cylinder is an important part of compressor compressed gas. Due to the large gas pressure, variable heat exchange direction and complex structure, the technical requirements are also high.

Piston assembly 

The piston assembly of diaphragm compressor consists of piston, piston ring, piston rod (or piston pin) and other parts. The piston and cylinder form a compressed volume. The reciprocating motion of piston assembly is transmitted to the diaphragm group through the hydraulic oil in the cylinder, so that it can be carried out.

Reciprocating motion to complete the cylinder gas compression cycle process.

Diaphragm group

The diaphragm group of the diaphragm compressor is of three-layer structure: two outer diaphragms are barrier layers, and a jar of diaphragms in the middle provides a discharge path through a fixed 0-shaped seal. At the same time, the cylinder is divided into hydraulic oil chamber and working gas chamber. Diaphragm usually

Made of rubber, plastic or metal, most diaphragm compressors are made of metal.

Gas valve

The gas valve of diaphragm compressor is used to control the gas suction and discharge of the cylinder. It opens and closes automatically under the action of pressure difference and spring force, so it is called automatic action valve. gas valve is usually composed of valve body, valve plate and spring. The air valve is on the compressor

One of the most important components which directly affect the operation is divided into inlet (suction) valve and outlet (exhaust) valve.

Connecting rod

The connecting rod of diaphragm compressor can be divided into split connecting rod and integral connecting rod according to the structure of its big end .

The split type connecting rod is used for the structure of crank and torsion shaft, its big end is fixed with connecting rod bolt when assembling with crank pin.

The integral type connecting rod is used for the structure of eccentric crankshaft. Because the stroke of the eccentric crankshaft structure is twice of the eccentricity, the integral connecting rod is limited.

It can be used in small refrigeration compressor. The integral connecting rod is simple in structure and easy to install. The split type connecting rod can be used in the refrigeration compressor with a long stroke because it fits with the crank pin of the crank shaft. The big end of the connecting rod is inlaid with a thin-walled bearing bush. In order to improve its wear resistance.The bearing bush has a layer of wear-resistant alloy.

There are two types of cuts for the split connecting rod big end.  flat cut  and oblique cut . 

Flat cut type:

The big end of the connecting rod is easy to be processed, and the connecting rod is not subject to shear force, but the big end has a large transverse size. The advantages and disadvantages of oblique incision are opposite to those of flat incision.The big end cap of the split type connecting rod big end is connected with the connecting rod body by connecting rod bolts, and the typical connecting rod bolts .It not only fastens the big end cap and connecting rod, but also positions the big end cap and connecting rod. The surface  is the locating surface of the connecting rod bolt, whose diameter is larger than the outer diameter of the threaded part. The bolt head is a plane.It is matched with the plane on the connecting rod support seat to prevent the bolt from rotating when tightening the nut.

The connecting rod bolt of diaphragm compressor bears severe alternating load, so it is necessary to reduce the stress concentration in the structure

Measures, such as the use of elastic bolts. The material of connecting rod bolt is high-quality alloy steel, such as 400, 350108, etc. Most connecting rod small end has bushing, the material is wear-resistant alloy, usually copper alloy.