Top 10 Pressure Switch Brand & Manufacturers

What is a Pressure Switch?

A pressure switch is a device that monitors and responds to changes in pressure within a system. It consists of a pressure - sensing element and an electrical switch mechanism. When the pressure sensed by the element reaches a set point, the switch either opens or closes an electrical circuit. This action can be used to control various processes such as starting or stopping a pump, opening or closing a valve, or activating an alarm to indicate abnormal pressure conditions.

History of the Pressure Switch

• The development of pressure switches can be traced back to the growth of industrial processes that required the control of fluid pressure. As early as the industrial revolution, the need for devices to monitor and manage steam pressure in boilers became evident. The first pressure - sensitive mechanisms were relatively simple and mechanical in nature, often using diaphragms or bellows to sense pressure changes and directly actuate a mechanical switch.
• With the advancement of technology and the expansion of industries such as oil and gas, chemical processing, and pneumatic systems, pressure switches became more refined. The use of better materials, improved manufacturing techniques, and more accurate calibration methods led to the development of more reliable and precise pressure switches. In the 20th century, the integration of electronics into pressure - sensing technology allowed for enhanced functionality, such as adjustable set points, differential pressure sensing, and digital communication capabilities.
• Today, pressure switches are an essential component in a wide range of applications. They are used in HVAC (Heating, Ventilation, and Air - Conditioning) systems, automotive systems, industrial automation, and many other fields. Their ability to provide accurate pressure control and reliable switching operations is crucial for the safety and efficiency of these systems.

Purpose of the Pressure Switch

• System Protection: One of the primary purposes of a pressure switch is to protect systems from over - pressure or under - pressure conditions. In a hydraulic system, for example, if the pressure exceeds a safe limit, the pressure switch can shut off the pump to prevent damage to the system components such as hoses, cylinders, and valves. Similarly, in a pneumatic system, it can prevent the build - up of excessive pressure that could lead to a rupture or explosion.
• Process Control: Pressure switches play a vital role in process control. In a water - treatment plant, they can control the operation of pumps based on the water pressure in the pipes. When the pressure drops below a certain level, indicating a need for more water flow, the pressure switch can activate a pump to increase the water pressure. In industrial manufacturing processes, pressure switches can regulate the flow of gases or liquids to ensure consistent product quality.
• Alarm and Monitoring: Pressure switches are often used to trigger alarms or provide status monitoring. In a compressed - air system, if the pressure falls below a critical level, the pressure switch can activate an audible or visual alarm to alert operators to a potential problem. In addition, in some automated systems, the status of the pressure switch (open or closed) can be monitored and logged to keep track of the system's performance over time.

Principle of the Pressure Switch

Most pressure switches operate based on the mechanical deformation of a pressure - sensing element. The sensing element, which can be a diaphragm, a bellows, or a Bourdon tube, changes its shape in response to the applied pressure. As the pressure increases or decreases, the sensing element deforms and this mechanical movement is transferred to an actuator that is connected to the electrical switch. For example, in a diaphragm - type pressure switch, the diaphragm is usually made of a flexible material such as rubber or a metal alloy. When pressure is applied to one side of the diaphragm, it deflects. This deflection moves a plunger or a lever that is attached to the diaphragm, which in turn actuates the electrical switch. The switch can be normally - open (NO), where the contacts are open in the absence of sufficient pressure, and close when the pressure reaches the set point. Or it can be normally - closed (NC), with the contacts closed until the pressure causes the switch to open.

Features of the Pressure Switch

• Accurate Pressure Sensing: Pressure switches are designed to provide accurate sensing of pressure changes. They have a specified pressure range and accuracy rating. The accuracy can vary depending on the type and quality of the pressure switch, but many modern switches can detect pressure changes within a few percent of the set point. This precision is crucial for applications where tight pressure control is required, such as in medical equipment or precision manufacturing processes.[!--empirenews.page--]
• Adjustable Set Points: Most pressure switches allow for the adjustment of the set point, which is the pressure value at which the switch activates. This adjustability provides flexibility in different applications. For example, in a heating system, the set point of the pressure switch that controls the boiler can be adjusted according to the specific requirements of the building's heating needs.
• Wide Pressure Range: Pressure switches are available in a wide range of pressure ratings, from very low pressures used in vacuum systems to extremely high pressures in industrial hydraulic and pneumatic systems. This versatility allows them to be used in various applications across different industries, from the low - pressure requirements of a domestic water - supply system to the high - pressure demands of an oil - drilling operation.
• Durability and Reliability: Given their role in often - harsh industrial and mechanical environments, pressure switches are built to be durable. The materials used in their construction, such as stainless steel for the housing and high - quality elastomers for the sensing elements, can withstand corrosion, vibration, and temperature fluctuations. Their reliable operation over a long period is essential to minimize downtime and maintenance costs in the systems they control.
• Electrical Compatibility: Pressure switches are designed to be electrically compatible with a wide range of control systems. They come with different electrical ratings, including voltage and current ratings, to match the requirements of the connected devices. Some pressure switches also offer additional electrical features such as dry - contact outputs (which can be used with different types of electrical circuits) or the ability to interface with programmable logic controllers (PLCs) for more advanced control functions.

Types of the Pressure Switch

• Diaphragm - Type Pressure Switch: As mentioned earlier, this type uses a diaphragm as the pressure - sensing element. Diaphragm - type pressure switches are suitable for low to medium - pressure applications. They are often used in HVAC systems, water - treatment plants, and pneumatic control systems. The flexibility of the diaphragm allows for sensitive pressure detection, and they can be designed to handle different types of fluids (gases or liquids).
• Bellows - Type Pressure Switch: Bellows - type pressure switches have a bellows as the sensing element. The bellows is a collapsible, accordion - like structure that expands or contracts with pressure changes. These switches are known for their high - precision pressure sensing and are often used in applications where accurate control of pressure is crucial, such as in some laboratory equipment and precision industrial processes. They can handle a wide range of pressures, from low to relatively high pressures.
• Bourdon - Tube Pressure Switch: The Bourdon - tube pressure switch uses a curved, hollow tube (the Bourdon tube) as the sensing element. When pressure is applied, the tube straightens or further curves, depending on the direction of the pressure. This mechanical movement is then used to actuate the switch. Bourdon - tube pressure switches are typically used for high - pressure applications, such as in hydraulic systems and high - pressure gas lines. They are known for their robustness and ability to handle high - pressure differentials.
• Electronic Pressure Switch: Electronic pressure switches use a pressure - sensing transducer to convert the pressure into an electrical signal. This signal is then processed by an electronic circuit to determine when to actuate the switch. These switches offer more advanced features such as digital displays for pressure readings, adjustable hysteresis (the difference between the turn - on and turn - off pressures), and the ability to communicate with other electronic devices via protocols like Modbus. They are becoming increasingly popular in applications that require more precise control and data logging.

Precautions for using the Pressure Switch

• Pressure Range and Over - Pressure Protection: Ensure that the pressure switch is used within its specified pressure range. Exceeding the maximum pressure rating can damage the sensing element and the switch mechanism. In systems where over - pressure is a possibility, consider installing additional over - pressure protection devices such as relief valves in conjunction with the pressure switch.
• Fluid Compatibility: Check the compatibility of the pressure - sensing element with the fluid in the system. Some materials used in the construction of the sensing element may react with certain chemicals or be damaged by abrasive fluids. For example, a diaphragm made of a particular rubber compound may not be suitable for use with a corrosive chemical solution.[!--empirenews.page--]
• Temperature Effects: Temperature can affect the performance of a pressure switch. The pressure - sensing element's characteristics may change with temperature, and the accuracy of the switch can be affected. In applications where temperature variations are significant, choose a pressure switch with temperature - compensation features or consider the temperature - induced errors in the system design and calibration.
• Installation and Mounting: Proper installation and mounting of the pressure switch are crucial. It should be installed in a location where it can accurately sense the pressure of the system. Mounting orientation can also be important, especially for some types of pressure switches like Bourdon - tube switches. Follow the manufacturer's instructions for installation to ensure correct operation and avoid false triggering or inaccurate readings.

Things to consider when purchasing the Pressure Switch

• Application Requirements: Determine the specific requirements of your application, such as the pressure range, accuracy, fluid type, temperature conditions, and the electrical load it needs to control. Based on these requirements, select a pressure switch with the appropriate characteristics. For example, if you need to monitor and control the pressure of a corrosive chemical process, you'll need a pressure switch with a compatible sensing element and suitable pressure range for that chemical.
• Type of Pressure Switch: Consider the different types of pressure switches available, such as diaphragm - type, bellows - type, Bourdon - tube, or electronic pressure switches. Evaluate the advantages and disadvantages of each type for your application. For a simple HVAC pressure - control application, a diaphragm - type pressure switch may be sufficient. But for a high - precision laboratory setup, an electronic pressure switch with advanced features might be more appropriate.
• Performance Characteristics: Look at the performance parameters of the pressure switch, such as the accuracy, repeatability, response time, and pressure range. These characteristics should match the demands of your application to ensure efficient and reliable operation. Compare different products and their performance metrics to make an informed decision.
• Cost and Budget: Establish a budget for the pressure switch purchase. The cost can vary significantly depending on the type, performance, and brand of the switch. Consider not only the initial purchase price but also the long - term costs such as maintenance, replacement, and potential impact on the overall system performance. Sometimes, a more expensive pressure switch with better performance and reliability may be a more cost - effective choice in the long run.
• Manufacturer Support and Training: Select a reputable manufacturer that provides good technical support and training. Operating and using pressure switches correctly may require some technical knowledge, and the manufacturer should offer resources such as user manuals, online tutorials, and customer support to help you get the most out of the pressure switch.

Terms of the Pressure Switch

• Set Point: The pressure value at which the pressure switch changes its state (opens or closes). It is a crucial parameter for setting the desired pressure control level in a system.
• Hysteresis: The difference between the turn - on and turn - off pressures of the switch. It is used to prevent rapid cycling of the switch when the pressure is near the set point and provides stability to the control system.
• Pressure Range: The minimum and maximum pressures that the pressure switch can accurately measure and respond to. It defines the operating limits of the switch in terms of pressure.
• Sensing Element: The part of the pressure switch that directly senses the pressure, such as a diaphragm, bellows, or Bourdon tube. The characteristics and performance of the sensing element play a significant role in the overall performance of the pressure switch.
• Contact Rating: The maximum voltage and current that the electrical contacts of the pressure switch can handle. It is important to ensure that the connected electrical load is within the contact rating to avoid damage to the switch and ensure safe operation.