A pressure switch is a mechanical or electronic device activated when the process fluid’s pressure reaches a predetermined threshold or set-point. Depending on the type of pressure switch, it may consist of a bourdon tube, piston, diaphragm, or membrane that deforms in response to the amount of pressure the system applies. Additionally, should the air pressure drop and additional air be required, the switch can turn the compressor back on.
Transducers and pressure switches are two different things. Pressure switches and pressure transducers are two different devices. While pressure switches are designed to detect pressure changes, pressure transducers convert pressure into an electrical output signal.
The following key components make up a pressure switch:
- Diaphragm– detects pressure. In most cases, the material is pliable and pressure-sensitive.
- Spring– An adjustment spring is used to adjust set-points or cutout points.
- Switch Lever– Used to make the switch work or to deactivate it.
- Electrical contacts– Permit current from an external power source to pass through them.
- Terminals– Terminals are essential components that allow you to connect an external power source to its contacts securely.
Types of Pressure Switches
- Mechanical Pressure Switch
Mechanical pressure switches offer a simple yet robust solution for less complex tasks. Using a spring and piston to manipulate the pressure at which they’re activated, those switches are best for coping with excessive voltages and amperages than a digital strain switch. The spring is the pressure opposing the inlet pressure, and its tension is adjusted with a precise set screw or knob, allowing for a controlled pressure of electric contact. If the pressure drops, the switch automatically resets to its original state for reliable performance.
- Electronic Pressure Switch
Electronic pressure switches are designed with a pressure transducer, typically a strain gauge, and additional electronics that convert signals into readable output. Compared to mechanical pressure switches, electronic pressure switches offer greater accuracy, less contact wear, wonderful long-time period stability, easy operation, and the cap potential to carry out heaps of switching cycles. This makes them ideal for various applications, from industrial and medical to automotive and aerospace.
A pressure switch may be utilized in an extensive variety of home and business applications, as indexed below:
- To screen and manage the machine air pressure, HVAC, fuel line cylinders, air pumps, etc., make use of air compressor pressure switches.
- When the engine’s oil pressure drops under the preset level, oil pressure switches decide while the oil pressure drops.
- Both business and home furnace pressure switches function as protection devices. They shut it down when there is low air pressure during the furnace start-up.
- A good pump pressure switch is used in residential and commercial buildings to bring water from the well and ensure enough pressure to provide water without being overpressed.
- Residential, commercial, and agricultural water pumps use pressure switches to regulate flow automatically.
- A vacuum pressure switch measures the vacuum withinside the device.
- These additives are observed in boilers, electric-powered heaters, air compressors, and transmission systems.
Considerations When Selecting Pressure Switches
When selecting pressure switches, it’s essential to consider several critical selection criteria. Our team of professionals has compiled a list of the most important criteria to consider when making your selection:
- Operating Temperature: The operating temperature of a material is a crucial consideration when selecting materials, as certain materials may degrade at higher temperatures. For this reason, it is essential to ensure that the chosen material can operate within the desired temperature range for the application.
- Process Fluid: The process fluid’s chemical properties are a critical factor in determining the type of material required for the wetted parts of the pressure-sensing component. These parts, which include ports, seals, and the pressurized side of the element, must withstand any chemical or physical attack from the process fluid. Failure to do so could lead to part degradation caused by corrosion, oxidation, or erosion. It is essential, therefore, that these parts are made of highly durable materials that can resist these attacks.
- Type of Pressure: Pressure switches are essential components of both positive and negative pressure systems. For positive pressure systems, pressure switches are typically used. Pressure switches specified for vacuum and compound pressure are required for negative pressure systems. Diaphragms are ideal for vacuum and low-pressure applications, while pistons are best suited for high-pressure applications.
- Pressure Range: As a professional, it is recommended to set the pressure switch’s set-point at 40 to 60% of the pressure range for safety reasons. This is often referred to as the operating range and is essential for the unit’s accurate functioning. Setting the set-point outside this range could cause the unit to malfunction, so ensure that the pressure range remains within the specified parameters.
- Operating Temperature: The operating temperature is essential when selecting the suitable material for your application. Certain materials can degrade when exposed to high temperatures. It is vital to ensure that the material you choose is ideal for the operating temperature of your application.
How does the pressure switch work?
A pressure switch is a passive device that requires nothing more than the presence or absence of pressure to function. For example, a diaphragm pressure compresses a calibrated spring to a predetermined set point at its core. When the spring tension reaches or exceeds this point, the contacts in an NO switch will close or open in an NC switch. This simple but effective device is a reliable and professional solution for many applications.
Overall, the pressure switch is a vital component that is used in a wide variety of applications, both in residential and industrial settings, to ensure that equipment is operating safely and correctly. By quickly and accurately detecting changes in pressure or vacuum levels, the pressure switch can help mitigate potential dangers and provide peace of mind to personnel and users alike.