Differential Pressure Instrumentation

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Brief Description

Differential Pressure (DP) Instrumentation measures the difference between two separate pressure points in a system, providing crucial data for flow rate, level, and filtration diagnostics.

In-depth Overview

DP instruments can be gauges (local reading) or transmitters (electronic output). The key component is a sensing element (diaphragm or capsule) exposed to a high pressure side (PHigh) and a low pressure side (PLow). The instrument measures the force caused by the pressure difference (ΔP=PHigh−PLow). This measurement is fundamental for primary flow elements like orifice plates and Venturi tubes, or for monitoring liquid levels in pressurized tanks. We also offer DP instruments with integral three- or five-valve manifolds to simplify installation, zero calibration, and safe isolation.

Specification

Parameter	Details
Measurement Range	0 to 5 mbar up to 0 to 20 bar DP
Type	Gauge (Mechanical) or Transmitter (Electronic)
Accuracy	±0.1% to ±1.5% of Span
Wetted Parts Material	SS 316L, Hastelloy, Monel
Line Pressure Rating	Up to 400 bar static pressure
Output Signal (Transmitter)	4−20mA (HART optional)
Connection Size	1/4′′ or 1/2′′ NPT (Female)
Process Connection	Two Ports (PHigh and PLow)

Applications

Flow Measurement: Used in conjunction with orifice plates or pitot tubes to calculate fluid and gas flow rates.
Filter/Strainer Monitoring: Indicates the pressure drop across the filter, signalling when the filter element needs cleaning or replacement.
Boiler Drum Level: Measuring the DP between the liquid and vapor space to accurately determine water level in high-pressure steam drums.
Leak Testing and Integrity Checks: Monitoring pressure decay in sealed systems.

Key Advantages

Multi-Purpose Sensing: A single technology used for three primary measurements: Flow, Level, and Pressure.
High Static Pressure Rating: Can accurately measure low differential pressures even when the line pressure is extremely high.
Turndown Capability: Electronic transmitters allow for wide turndown ratios, making the instrument flexible across various flow ranges.
Integrated Safety: Designed with overpressure protection to handle high static pressure fluctuations.

Payment and Shipping

We accept secure methods like T/T and L/C. DP instrumentation is often manufactured to order based on the required differential and static pressure ranges, with typical lead times of 3-5 weeks. We prioritize robust packaging, including reinforced corners and precise cushioning for the highly calibrated sensor cell to ensure zero shift upon arrival at your site.

Frequently Asked Questions

Q: What is the purpose of the manifold that often accompanies a DP transmitter?
A: The manifold (usually 3-valve or 5-valve) allows technicians to safely isolate the instrument, equalize the pressure to check for zero drift, and vent the process pressure before removal, all without shutting down the entire line. It is a critical safety and maintenance accessory.

Q: How does a DP instrument measure flow?
A: Flow is measured indirectly. A primary element (like an orifice plate) creates a restriction in the pipe, causing a velocity increase and a corresponding pressure drop. The DP instrument measures this pressure drop, which is then calculated using the Bernoulli principle (Flow∝ΔP) to determine the volumetric flow rate.

Q: Is there a risk of over-ranging the instrument?
A: Yes. If the static pressure on one side is too high relative to the other, it can damage the diaphragm. Our instruments are designed with high maximum static pressure ratings and over-range protection features to mitigate this risk.

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Differential Pressure Instrumentation Manufacturers

Wuxi Huihua Special Instrumentation Co., Ltd. was established in December 2001, the registered capital is 5 million yuan, the existing staff of more than 50 small and medium-sized joint-stock enterprises.
The company specialises in the production of various types of special instruments, alternative to the localisation of imported instruments.To seismic pressure gauge, seismic electric contact pressure gauge, stainless steel pressure gauge, diaphragm corrosion-resistant pressure gauge, marine pressure gauge and other series as the main products. On the basis of field instruments, we have developed various kinds of pressure transmitters, pressure controllers, digital pressure gauges and so on. There are more than 30 series and 3000 specifications. Products are widely used in petroleum, chemical, paper, metallurgy, mining, chemical fibre, electric power, food, environmental protection, rubber and plastic, hydraulics and many other industries, and more than 2,000 domestic customers to establish a friendly relationship with the national large and medium-sized enterprises to establish a good partnership, won the majority of users praise, and set up a corporate brand image.