Pressure switch is a device that triggers electrical signal output through internal mechanical structure or electronic components when the input pressure reaches a set value.
First, the working principle
Mechanical pressure switch:
It is usually composed of pressure sensitive elements (such as bellows, diaphragms, etc.), transmission mechanisms and microswitches.
When the measured pressure acts on the pressure sensitive element, it deforms, and the micro switch is driven by the transmission mechanism, so as to realize the on-off switch of the circuit.
For example, when the pressure rises to the set value, the bellows are compressed and deformed, and the ejector rod is pushed to close the micro-switch, sending out a signal that the pressure has reached; When the pressure drops to a certain value, the bellows recover and the microswitch is disconnected.
Electronic pressure switch:
Pressure sensor is used to convert pressure signal into electrical signal, which is amplified and compared by signal processing circuit.
When the pressure reaches a set value, the signal processing circuit outputs a control signal that triggers switching elements such as relays or transistors to act.
For example, the pressure sensor detects the pressure change, outputs the corresponding voltage signal, and compares it with the set pressure value after A/D conversion. When the pressure exceeds the set value, the microprocessor outputs the control signal to make the relay close.
2. Application field
Industrial Automation:
In hydraulic system and pneumatic system, it is used to monitor and control pressure to ensure the normal operation of the system. For example, when the pressure of the hydraulic system is too high, the pressure switch sends a signal to stop the system from working and prevent equipment damage.
In the water supply and gas supply system, the pressure can be automatically controlled and protected. For example, when the water supply pressure is lower than the set value, the pressure switch starts the pump and increases the water supply pressure.
Household Appliances:
For example, in air conditioners, refrigerators and other equipment, pressure switches are used to control the pressure of the refrigeration system to ensure the normal operation and safety of the equipment. For example, the high-pressure pressure switch in the air conditioner cuts off the power supply when the pressure of the refrigeration system is too high to prevent the compressor from being damaged by overload.
In the electric water heater, the pressure switch can detect the pressure of the inner tank, and automatically drain the pressure when the pressure is too high to prevent explosion accidents.
Automotive industry:
In the engine control system, the pressure switch is used to monitor the oil pressure, fuel pressure, etc., and issue an alarm when the pressure is abnormal to remind the driver to deal with it in time.
In the brake system, the pressure switch can detect the brake fluid pressure to ensure the normal operation of the brake system.
Iii. Characteristics
High accuracy: It can accurately detect pressure changes and trigger switch action near the set pressure value.
Strong reliability: The use of high-quality materials and advanced manufacturing processes, with good vibration resistance, impact resistance and corrosion resistance, can be long-term stable operation in harsh working environment.
Easy adjustment: The pressure setting value can be adjusted according to actual needs to meet different application requirements.
A variety of output forms: there are two common output forms of normally open and normally closed, and different electrical signal output modes such as relay output and transistor output can be selected according to needs.
Flexible installation: small size, a variety of installation methods, can be directly installed on the pipe, container, can also be installed through the installation of accessories such as brackets.
4. Select precautions
Measuring range: Select the right pressure switch according to the pressure range that needs to be detected in the actual application to ensure that its measuring range can cover the required pressure value.
Accuracy requirements: Select the pressure switch of the corresponding accuracy level according to the requirements of the pressure control accuracy of the application scenario.
Output form: According to the requirements of the control system to choose the appropriate output form, such as normally open, normally closed, relay output, transistor output, etc.
Environmental adaptability: Consider the use of the pressure switch environment, such as temperature, humidity, corrosion and other factors, choose the corresponding protection level and environmental adaptability of the product.
Brand and quality: Select well-known brands and reliable quality pressure switches to ensure stable performance and long service life.
Price factor: under the premise of meeting the performance requirements, choose a reasonable price pressure switch to reduce the cost.
