A differential pressure sensor measures the difference in pressure between two points. It is often used to measure the pressure within a closed system, where it may be used to calculate the pressure of one point relative to another. It is used widely in applications such as clean rooms, heat exchangers, refineries, petrochemical plants, and chemical plants.
A differential pressure sensor indicates the difference between two pressure points within a process, such as the inlet and outlet of a pump. For example, if the pressure at one inlet port is 100 psi and the pressure at the other port is 80 psi, then the differential pressure is 20 psi (100 psi-80psi).
Closed Tank Level Monitoring: Differential pressure measurement is widely used as a method for monitoring the level of closed tanks. For the level of the contents in the vessel, the differential pressure between the liquid and the gaseous phase is determined. Typical measuring instruments have two adjacent process connections for the pressures P1 and P2.
HVAC Filtration: As a filter cartridge starts to become obstructed with contaminants, the pressure between the inlet and outlet ports increases and efficiency drops. Operators can use the differential pressure as an indication to detect buildups and clogging in pipes and pumps. When the differential pressure reaches a certain limit, the operator knows it is time to change the filter preventing damage to the system.
Flow Monitoring: Bernoulli’s principle states that an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid’s potential energy. An orifice plate or venturi is often used to reduce the diameter inside the pipe. A differential pressure gauge can then be installed, connecting the high-pressure side to the larger diameter and the low-pressure side to the smaller diameter, to measure the difference in pressure before and after the orifice and determine the flow rate. This provides a high accuracy solution at a low cost.
Leak Detection: In a leak detection based on differential pressure measurement, the leak is detected by measuring pressure difference between a reference component, which is leak tight, and a tested component using a differential pressure sensor. When the tested component is leaking, the pressure inside it decreases and the pressure difference with the reference is measured.
Mechanical vibration: Vibration has a negative impact on gauge accuracy. It is difficult to read the pointer on a dial when the device is vibrating. Vibration can also cause damage to the pointer mechanism and internal components.
A liquid-filled case is the most cost-effective way to protect pressure gauges from vibration. Remote mounting with additional diaphragm seals with capillary connection is also recommended.
Extreme pulsation: Pulsation is defined as regular instances of rapid pressure changes in the measured medium. In this condition, the pointer flutters wildly, making it difficult to read the pressure value on the device. Prolonged pulsation can cause the internal components begin to wear down which shortens the lifespan of the device.
To reduce pulsation, pulsation dampeners such as a needle valve or socket restrictor can be used. Pulsation dampeners are commonly found in applications such as pump discharge and boiler house applications to reduce the impact of pulsations.
Pressure spike: Spikes occur when the pressure sharply increases and then suddenly drops. Broken or bent pointer or broken stop pin are visible signs of pressure spike.
Dampening solutions such as liquid-filled gauge or additional accessories like restrictors, needle valves, or diaphragm seal with capillary are recommended. A wider pressure range can also be considered to prevent pressure spike.
Overpressure: Overpressure occurs when the pressure device is operating near or pass its maximum range. A rupture will happen when the internal components such as the Bourdon tube no longer holds pressure and begins to deform and split. This will cause process media to escape, leading to contamination and expensive downtime to re-sterilize the affected process.
Choosing a wider operating range can provide a larger allowance for the measured process. Users can prevent damage from overpressure by attaching an overpressure protector.
Clogging: Clogging is a common issue for process medium containing suspended particles in applications for wastewater, paper and pulp, dust collection, etc. Contaminants buildup will affect the efficiency of the pressure device.
Y-strainers is used to remove unwanted particles in the process medium. Diaphragm seals with capillary connections also eliminate the risk of buildup in the tubing.
T-5000 Differential Pressure Gauge
- For air and non-combustible, compatible gases
- Easy to read precision scale
- Low cost
- Compact in size
- Zero adjustment screw
- Over pressure protection
- Durable and rugged housing
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T-2000 Differential Pressure Gauge
- For air and compatible gases
- 5% accuracy of full scale
- Low cost
- Compact in size
- Suitable for industrial use
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T-3000 Differential Pressure Switch
- For air and non-combustible, compatible gases
- Dual scaled adjustment knob
- Low cost
- Compact in size
- Excellent for HVAC applications
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TG/TA Smart Pressure Transmitter
- Updating time of output current in 90 ms
- Improved performance, increased accuracy and greater stability
- Two years stability of 0.15%
- 0.1% accuracy
- 4-20 mA output plus direct digital HART communication
- Automatic zero calibration by simply pressing a button
- Explosion proof and weather proof
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DP Smart Pressure Transmitter
- Updating time of output current in 200 ms
- Improved performance, increased accuracy and greater stability
- Two years stability of 0.2%
- 0.2% accuracy
- 4-20 mA output plus direct digital HART communication
- Automatic zero calibration by simply pressing a button
- Explosion proof and weather proof
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LT Smart Pressure / Level Transmitter
- Updating time of output current in 200 ms
- Improved performance, increased accuracy and greater stability
- Two years stability of 0.15%
- 0.1% accuracy
- 4-20 mA output plus direct digital HART communication
- Automatic zero calibration by simply pressing a button
- Explosion proof and weather proof
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RD/RT Remote Diaphragm Seal Pressure Transmitter
- Maximum temperature 280°C
- Multiple connection mode – flange type/tri-clamp type
- Extremely hot and cold temperature
- Stainless steel with PPC coating capillary
- Food industry application: Vegetable oil available for fill fluid
- IDF tri-clamp / union screw connection
- Fast and dynamic response
- Improved performance, accuracy and stability
- Oil-free treatment and water-free treatment options
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