Pressure Protection Instructions for Small Refrigeration and Heating Cycle Integrated Units

In order to ensure the reliable operation of the refrigeration system, the equipment and system must be equipped with reliable devices
.

These reliable devices must be sound and effective
.


In the refrigeration system of the small refrigeration and heating cycle integrated unit, there are not only monitoring equipment such as pressure gauges, but also some reliable equipment that can play an automatic protection
.

Once the pressure is abnormal, the reliable equipment can automatically act to reduce the pressure of the equipment or automatically shut down to prevent accidents
.

Therefore, the pressure protection reliable equipment must not be arbitrarily removed or the set value adjusted
.

These devices include: 1.
Reliable valve: There are two types of reliable valve (pressure type) for direct discharge and reliable valve for bypass pressure reduction (differential pressure type)
.

The set pressure of the reliable valve of different equipment is different
.

The reliable valve must be inspected regularly, once a year, and sealed with lead; the reliable valve must be re-calibrated after taking off to ensure its tightness and accuracy
.

In order to facilitate maintenance and replacement, it is required to set a stop valve (except the compressor) before the reliable valve, but it must be in an open state
.

The high pressure valve of the piston compressor should automatically open when the pressure difference between the suction and exhaust sides reaches 1.
6MPa; the medium pressure valve of the low pressure stage of the two-stage compressor should automatically open when the pressure difference between the suction and exhaust sides reaches 0.
6MPa
.

The opening pressure of the reliable valve of the high-pressure equipment in the system is set to 1.
85MPa, and the low-pressure equipment is 1.
25MPa
.

　　2.
Pressure relay: divided into two types: pressure relay and differential pressure relay
.

The pressure relay is mainly used for high exhaust pressure protection, low suction pressure protection, high intermediate pressure protection, water cutoff protection, etc.
The differential pressure relay is mainly used for oil pressure differential protection and reliable protection of pump liquid supply
.

　　Whether the operation of the refrigeration system of the small refrigeration and heating cycle integrated unit is in a reliable state, the main monitoring method is to display the pressure of each part of the system through the pressure gauge
.

In this way, on the one hand, it is convenient for normal operation and management, such as evaporating temperature, condensation temperature, etc.
can be judged by pressure, on the other hand, it can timely detect whether there is abnormality or overpressure in each equipment, and control or alarm
.

If the pressure gauge in the refrigeration system is damaged, it must be scrapped immediately and replaced with a pressure gauge produced by the official manufacturer, with a certificate of conformity and lead seal, and the accuracy and range meet the requirements
.