What is the clearance volume of an ammonia compressor?

Due to the needs of ammonia compressor structure, manufacturing, assembly, operation, etc., some parts of the cylinder have a certain space or gap, which is called the clearance volume (also called harmful volume or gas storage).

Ammonia compressors have clearance volumes in the following locations:

1. The gap between the piston end face and the cylinder end face at the end of the piston exhaust stroke;

2. The gap between the cylinder mirror surface and the outer circle of the piston (from the end face to a piston ring);

3. The volume formed by the passage from the valve to the cylinder volume.

The volume of the valve itself, such as the channel of the valve seat, the spring hole, etc. (the channel volume accounts for a large proportion, and the annular gap has a very small value). The clearance volume of the ammonia compressor is sometimes required by the structure, and sometimes it is difficult to avoid. For example, when the piston moves to the exhaust end position, the gap between its end face and the cylinder end face is mainly considered by the following factors:

1. When the piston moves periodically, the heat generated by friction and compressed gas causes the piston to expand due to heat, resulting in radial and axial elongation. In order to avoid collision between the piston and the cylinder end face and the piston and the cylinder wall being stuck, the clearance volume is used to clear it.

2. For compressed gas containing water droplets, the water droplets may gather during compression. In this case, the clearance volume can prevent water hammer caused by the incompressibility of water.

3. There is always a deviation between the manufacturing accuracy and the assembly of parts and the requirements. The moving parts may become loose during the movement, which will increase the gap between the joint surfaces and the total size of the parts.

The clearance volume formed by the passage from the valve to the cylinder volume is mainly due to the arrangement of the valve that is difficult to avoid.

When the ammonia compressor is working, the clearance volume reduces the volume of gas sucked by the intake valve, and the corresponding exhaust volume is reduced. Therefore, when designing the cylinder, the influence of the clearance volume on the exhaust volume should be considered in advance. When designing an ammonia compressor, the clearance volume should be as small as possible in consideration of productivity, manufacturing, assembly operation, etc. However, sometimes in order to adjust the piston force, the clearance volume is increased accordingly, which is also often encountered when designing a moving ammonia compressor.