Compressor

Reciprocating Compressor M Series Operation Manual 4M/6M/8M

High pressure protection equipment (HP)

When the discharge pressure on compressor becomes abnormally high. HP switch shuts off the motor circuit automatically to stop the operation of compressor. Prevents system ruptures and refrigerant leaks.

Control of the compressor capacity:

Low pressure control equipment (LP)

The number of capacity control steps in a compressor are determined by the number of cylinders. Generally two cylinders are considered one bank. Therefore, capacity control of four steps is available for eight cylinders, three steps for six cylinders, and two steps for four cylinders. Capacity control is performed by detecting suction pressure a low pressure control switch is used. It automatically controls opening/closing of the solenoid valve connected to the unloader piston in the capacity control mechanism of compressor.

Adita,

What Lyn says is 100% correct as always, but I thought you might be looking for something a little more basic to help understand?

Look at it this way, lets say you only have an air compressor of two stages only LP and HP. LP is the larger diameter cylinder, it will take air at atmospheric pressure and compress it (force it) into the smaller diameter HP stage where it is then compressed further.

For example a HP compressor unit for a drilling unit may be four stages, first stage roughly 4" diameter piston but by the fourth stage the piston is a bit smaller than 1". With this we can create 3000+ psi with 20+/- hp. For volume and redundancy we normally have 3 to 5 units lined up.

DISCLAMER: Diameters and Exact HP are only generalized for practical purposes.

Tim

Mr. Aditya !!!!!!!!

Your previous question was far ahead of this. I can not believe it if you ask function of HP and LP cylinders.

It is beter you take out your theory books are read about reciprocating compressors. Or better you google on net to get better results.

both the cylinders are used to increasing the pressure but in single cylinder substance compresser to high pressure automatically temp. increases with the help of inter coller we are using two cylinders like hp & lp in inter cooling process we decreasing the temp. in constant pressure process that is called intercooling

• Efficiency of the gas cycle increases as the compression ratio is increased. However, there are practical limits when it comes to increasing the pressure ratio. First of all, increasing the pressure ratio increases the compressor discharge temperature. This can cause the temperature of the gasses leaving the compressor to exceed the metallurgical limits of the casing.
• Further compression of the high temperature gases will consume more power as the volume handled will be more.
• To economize the construction of the compressor in normal material of construction which can withstand nominal gas temperatures, and to keep the size of the machines within working limits, it is better to cool down the gases again near to ambient temperature before further compression.
• So first stage of compression is achieved in LP stage or LP cylinder and further compression to higher pressure is achieved in HP stage or HP cylinder.

I hope this will serve your purpose.