A pressure transducer is a device that generates a signal in response to a pressure measurement of a liquid or gas. In this context, pressure is defined as the force per unit area that is required to maintain a substance’s density, level, flow, speed, or altitude. The technology, configuration, application, performance specifications of pressure transducers can vary widely.
Many systems and operations depend upon pressure transducers for accurate and reliable measurements. Pressure transducers are commonly used in automotive, medical, industrial, agricultural devices that rely on precise measurements for consistent operation. Pressure transducers are used in engines to measure incoming, outgoing, and system pressure. The functionality of automotive brakes requires a complex system of pressure transducers. Pressure transducers are used in tanks to measure fluid levels. Hyperbaric therapy relies upon pressure sensors to treat a variety of medical conditions. Vacuum cleaners utilize pressure transducers to regulate suction. Oil pressure transducers display a warning when the force in the fuel tank falls outside of the designated safety range. Friction increases to correct low oil pressure levels. High oil pressure indicates an engine malfunction.
How does a pressure transducer work?
A pressure transducer measures pressure. Changes at the pressure source cause the sensing element, also known as a diaphragm, to flex. The alterations to the diaphragm are recorded as measurements.
Measurements collected from the diaphragm response are translated into signals that travel on the transduction element to provide instructions to the control system. Each step in the process is optimized to suit the unique requirements of the system and environment.
Types of Pressure Sensing Technologies and Working Principles
Pressure transducers are available in many different shapes and sizes, but the most common designs are cylindrical. The two main components of a pressure transducer are the force collector and the transduction element. The center of the device holds the force collector, or diaphragm. A pressure port is at one end. This is typically a threaded, barb fitted, open, or bolted component. At the other end of the cylinder is a signal transmitter.
Force collectors are sometimes referred to as diaphragms or pressure measurement chambers. There are many types of pressure sensing technologies and each offer adjustable configurations. There are options for outputs, electrical connections and pin outs, pressure ranges, and process fittings. Originally, force collectors were mechanical u-tube manometers made of glass. A Wheatstone bridge is another type of diaphragm. There are two legs of a bridge circuit, and one of the legs is unknown. Wheatstone bridges provide precise measurements and can be mounted to the transmitter diaphragm in different ways to fit the conditions of differently pressured environments. The functionality of diaphragms depends upon piezoresistive technology. Piezoresistivity is a change in electrical resistance in response to force. Piezoresistive technology is responsible for accurate pressure measurements. Pressure sensors need to be calibrated at least once per year
Transduction elements translate and communicate signals between the operator and sensor. Traditional outputs feature 0-5V and 0-10V signals. 0-10V signals have twice the span of 0-5V signals. Zero-based elements do not produce a signal when the pressure levels are at zero in a standard gauge unit. No information is transmitted if a wire is cut or a component is malfunctioning. With zero-based signal systems, it is not possible to distinguish between a zero-pressure level and broken equipment.
Transduction elements use methods such as dependent resistive, inductive, or capacitive to generate signals. There are many options for these component technologies, and each technology follows unique working principles. Resistive transducers use bourdon tubes, liquid columns, and manometers. Inductive transducers use Linear Voltage Differential Transformers (LVDT). Capacitive transducers are passive and utilize plates to conduct measurements.
Specific pressure transducer models are designed for indoor environments, and specific models are designed for outdoor environments. All types of pressure transducers must adhere to rigorous standards that encompass details such as span units and ranges. Spans describe the difference between the lowest and highest points in the measurement configuration. Ranges describe the minimum and maximum pressure capacities. The simplest pressure transducers are inexpensive, compact, and ideal for situations without electrical noise. Indoors, pressure transducers are found in devices such as HVAC units. The outdoor models are typically weatherproofed and include lightning protection, which is especially critical for devices that track barometric pressure. The transducers that are designed for oil and gas use are certified to withstand hazardous and harsh conditions. Pressure transducers used for drilling and exploration can withstand the intensity of pumping mud and cement. They must also be explosion-proof.
For a comprehensive list of pressure transducers and detailed product consultation, contact TechStar. Since 2001, TechStar continues to provide the most reliable analytical tools, devices, and training to businesses like yours. With a multitude of manufacturing partners and exceptional customer service, TechStar can guarantee the perfect, innovative solution for all your pressure transmission needs.