The application of vacuum pressure switches in vacuum pump systems

Vacuum pressure switches are widely and crucially used in vacuum pump systems. Their core function lies in ensuring the stable operation of the system, equipment safety and process accuracy through pressure monitoring and control. The following elaborates on specific application scenarios, performance matching, and system optimization value:

First, core application scenarios

Vacuum pump start-stop control

Working principle: When the pressure in the vacuum chamber reaches the preset threshold (such as -90 kpa), the switch contact closes and sends a stop signal to the vacuum pump controller. When the pressure rebounds to the set upper limit (such as -70 kpa), the switch is disconnected and the pump set is restarted.

Typical case: In semiconductor wafer etching equipment, the vacuum pump needs to maintain the cavity pressure within the range of -95 kpa to -85 kpa. The switch prevents the pump set from idling or overloading through real-time monitoring.

Abnormal pressure alarm and protection

Fault monitoring: If the pressure remains persistently below -101 kpa (close to absolute vacuum) or above -50 kpa (possibly with leakage), the switch will trigger an alarm and cut off the power supply to the pump set to prevent motor burnout or process failure.

Linkage mechanism: In conjunction with the gas mass flowmeter, when abnormal flow at the exhaust end of the vacuum pump is detected, the switch can be linked to close the intake valve to prevent the backflow of contaminants.

Collaborative control of multiple pump groups

Cascade control: In large vacuum systems (such as vacuum coating machines), the main pump and the forepump start in stages through pressure switches. When the pressure in the main chamber drops to -98 kpa, the forepump stops and the main pump independently maintains the vacuum degree.

Redundant backup: In a dual-pump parallel system, if the main pump fails and the pressure rises to -60 kpa, the standby pump switch will automatically start to ensure process continuity.

Second, key points of performance matching

The pressure range is adapted to the accuracy

For coarse vacuum scenarios (such as food packaging machines) : Select a switch with a pressure control range of -100 kpa to 0kPa and an accuracy of ±2%, with a response time of less than 0.5 seconds, to quickly meet the vacuuming requirements of packaging bags.

High vacuum scenarios (such as mass spectrometers) : A switch with a pressure control range of -101 kpa to -10 kpa and an accuracy of ±0.5% is adopted, combined with a helium mass spectrometer leak detector, to ensure a leakage rate of less than 1×10⁻⁹ Pa·m³/s.

Medium resistance and anti-pollution design

Corrosive gas treatment: In PECVD equipment of the photovoltaic industry, switches need to withstand corrosive atmospheres containing silane (SiH₄). Hastelloy diaphragms and PTFE sealing structures are adopted, with a service life of more than 5 years.

Dust environmental protection: In the lithium battery electrode sheet drying equipment, the switch is equipped with a dust cover and a self-cleaning filter screen to prevent aluminum powder from blocking the pressure channel.

Durability of mechanical structure

High-frequency start-stop tolerance: In vacuum heat treatment furnaces, the switch needs to withstand more than 200 start-stop cycles per day. It adopts silver-plated contacts and a double-spring structure, with a contact resistance of less than 5mΩ and an electrical life of more than 10⁶ times.

Vibration condition adaptation: In the vehicle-mounted vacuum pump system, the switch, through shock-absorbing brackets and epoxy resin potting process, ensures that the pressure monitoring accuracy is maintained even at a vibration acceleration of 5g.

Third, the value of system optimization

Energy consumption and lifespan improvement

Energy-saving effect: In the vacuum suction cup handling system, the intermittent operation of the pump set is controlled by a pressure switch, which saves more than 30% energy compared to the continuous operation mode, and at the same time reduces the risk of pump oil emulsification.

Extended service life: In the chemical vacuum distillation tower, the switch precisely controls the start and stop of the pump set, preventing crystallization and blockage in the pump cavity, thus extending the service life of the mechanical pump to over 8 years.

Process stability guarantee

Temperature compensation function: In the vacuum freeze dryer, the switch is equipped with an internal temperature sensor to compensate for pressure drift in an environment ranging from -40℃ to 80℃, ensuring the accuracy of the freeze-drying curve within ±1%.

Multi-parameter linkage: In the vacuum melting furnace, the switch is linked with the oxygen content analyzer. The heating system is only allowed to be turned on when the vacuum degree is lower than -99 kpa and the oxygen content is less than 10ppm.

Intelligent maintenance

Self-diagnostic function: High-end switches integrate pressure curve recording and fault code storage, and display the data of the last 100 actions through the HMI interface to assist in fault traceability.

Remote monitoring: Supports the Modbus RTU protocol to upload pressure data to the SCADA system and achieve predictive maintenance of the vacuum pump group.

Fourth, typical application cases

Photovoltaic cell production: In the vacuum system of the diffusion furnace, a switch with a pressure control range of -100kPa to -10 kpa and a switching difference of ≤1kPa is adopted to ensure that the pressure fluctuation inside the furnace is less than ±0.5kPa, guaranteeing the uniformity of PN junction doping.

Biopharmaceutical freeze-drying: In the vial freeze-dryer, the switch regulates the speed of the vacuum pump through a PID control algorithm, stabilizing the pressure during the sublimation stage at -95 kpa ±2kPa to prevent bottle ejection or collapse.

Aerospace testing: In the satellite vacuum thermal test chamber, the switch adopts a dual-redundant design (main switch + backup switch), and the pressure signal is selected from three to two, ensuring that the reliability of the chamber leakage rate detection reaches 99.99%.

The vacuum pressure switch significantly enhances the automation level, operational efficiency and safety of the vacuum pump system through precise pressure monitoring and flexible control logic. With the advancement of sensor technology, communication protocols and materials science, future switches will develop towards a wider pressure range (such as -101 kpa to 10MPa), higher protection levels (IP69K) and more intelligent diagnostic functions, further promoting the in-depth application of vacuum technology in high-end manufacturing fields.