Air compressor pressure relay is an important device in the pneumatic system, helping to protect the air compressor from damage due to too high or too low pressure. This article Tan Long will provide detailed information about the concept, structure, operating principle, how to adjust the relay as well as cases where this device needs to be adjusted.
What is an air compressor relay?
Air compressor relay (also known as air compressor role) is a type of switch that automatically closes or opens an electrical circuit based on pressure changes in the pneumatic system. It is used to control the operation of the air compressor, ensuring that the pressure is always maintained within a safe and optimal range.
Air compressor relay structure
Based on the purpose of use, relays are divided into two types: high pressure relays and low pressure relays.
Low pressure relay
Low pressure relay is used to protect the air compressor from damage when the pressure is too low causing ineffective lubrication and damage to the motor.
Structure
Low pressure relays usually consist of the following main components:
- Bellows: It is a thin metal tube that can expand and contract when pressure changes.
- Spring: Creates a force that opposes the pressure, keeping the bellows in a balanced position.
- Electrical contacts (Contacts): Connected to the air compressor control circuit.
- Adjusting Screw: Used to change the spring tension, thereby adjusting the operating pressure level of the relay.
- Pressure Connection: Connect the relay to the pneumatic system.
Working principle
When the pressure in the pneumatic system drops below the set level, the bellows will contract, the spring will exert a force that opens the electrical circuit. The compressor will stop working. When the pressure recovers to a safe level, the bellows will expand and the electrical contacts will close. The air compressor will operate again.
High pressure relay
The high pressure relay works on the opposite principle of the low pressure relay. It helps protect the air compressor when the pressure is too high, causing the compressor to overload.
Structure
High pressure relays are similar in construction to low pressure relays, but are designed to operate at higher pressure levels. The main components include:
- Bellows: Withstand high pressure.
- Spring: Has higher stiffness, creating greater resistance.
- Electrical contacts (Contacts): Usually designed to interrupt the electrical circuit when pressure increases.
- Adjusting Screw: Allows adjustment of the circuit breaker pressure level.
- Pressure Connection: Connect to pneumatic system.
Working principle
When the pressure in the pneumatic system exceeds the set level, the bellows will expand, overcome the spring force and act on the electrical contacts. At this time, the circuit will be interrupted, the air compressor will stop working. When the pressure drops below the allowable level, the bellows will contract, the spring will push the electrical contacts back to the closed position, the air compressor will work again.
Air compressor pressure relay function
Air compressor pressure relay plays a very important role in protecting and operating the compressed air system safely and efficiently. Here are its main functions:
Relay used to protect air compressor when pressure is too low
When the pressure in the pneumatic system drops below the allowable level (for example due to an air leak), the low pressure relay will cut off the electrical circuit, stopping the operation of the air compressor. This helps protect the compressor from a lack of lubrication and cooling oil, leading to damage to internal components.
Relay protects the machine when high pressure exceeds the allowable level
When the pressure in the pneumatic system exceeds the set level (e.g. due to a faulty safety valve). Air compressor role will immediately cut off the circuit, stopping the operation of the air compressor. This avoids the risk of overload, gas tank explosion, causing danger to users and damage to equipment.
Check air compressor oil performance
Some pressure relays also have the function of checking the performance of the compressor oil. When the lubricating oil pressure drops low, the relay will cut off the circuit, warning the user about the lack of oil, need to add or replace new oil. Thanks to that, the machine operates smoothly, increasing its lifespan.
Cases where pneumatic pressure relay adjustment is required
The thing air compressor relay adjustment is necessary in the following cases:
- Newly installed air compressor: It is necessary to set the operating pressure level to suit the usage requirements.
- Replace new relay: The new relay needs to be adjusted to operate in sync with the system.
- Changing usage needs: When it is necessary to change the working pressure level of the air compressor.
- Air compressor is not working properly: The air compressor switches on and off continuously or does not reach the desired pressure level, possibly due to a faulty relay.
- After a period of use: Relay parts may wear out, leading to errors during operation.
How to adjust pneumatic pressure relay
The process of conditioning pneumatic pressure relay adjustment includes the following steps:
- Step 1: Preparation:
- Disconnect the power to the air compressor.
- Release all compressed air from the tank.
- Prepare necessary tools such as screwdrivers and pressure gauges.
- Step 2: Locate the adjusting screws:
- Load opening pressure adjustment screw: (Usually marked “+” or “High”) is used to adjust the pressure level at which the air compressor starts charging air into the tank.
- Load cut-off pressure adjustment screw: (Usually marked “-” or “Low”, “Diff”) is used to adjust the pressure level at which the air compressor stops charging air.
- Step 3. Make adjustments.
- Proceed to reset the pressure relay.
- Step 4: Check:
- Power supply to air compressor.
- Observe the pressure gauge and monitor the on/off process of the air compressor.
- If the air compressor operates stably and reaches the desired pressure level, the adjustment process is successful. Otherwise, step 3 needs to be repeated.
Pressure relay setting
Pressure relay setting has 2 main operations: Load opening setting and Load disconnect setting.
Install the load opening pressure relay
To set the load opening, we proceed to adjust the load opening pressure screw. Turn the screw clockwise to increase the load opening pressure and counterclockwise to decrease the pressure. Operate moderately, then check the pressure level with the gauge to see if it is correct as required. Continue to adjust if it is not correct.
Install the load cut-off pressure relay
Similar to the load opening setting operation, to set the load cut-off pressure relay, we proceed to adjust the load cut-off pressure screw. Turn the screw clockwise to increase the load cut-off pressure and counterclockwise to decrease the pressure. At the same time, adjust and read the parameters on the pressure gauge.
Conclude
Air compressor pressure relay is a small device but plays a very important role, ensuring the safety and performance of the pneumatic system. Understanding the structure, operating principles, and how air compressor relay adjustment will help users operate machines effectively, avoid unnecessary damage and prolong the life of the equipment. Hopefully the article has provided you with useful information about air compressor role.
See also:
