Pressure Gauge
Pneumatic Systems
November 4, 2020
Temperature Gauge
January 26, 2022Pressure Gauge
A pressure gauge (also known as a manometer) is one of the most widely used instrumentation devices for measuring pressure in a pipe or vacuum. Due to its broad range of applications, pressure gauges are available in various models, sizes, materials, and consequently, price ranges in the industrial market. They are extensively used in industries such as oil and gas, petrochemical, refineries, steel, power plants, and more, and their main function is to display and control the pressure of fluids within pipelines.
Isatis Farayand Abzar Company supply a wide range of general-purpose pressure gauges as well as specialized pressure gauges required by various industries, from reputable European and Asian brands, including Rosemount, Danfoss, Wika, Nouvafima, Ashcroft, and more.
Types of Pressure Gauges
Pressure gauges are constructed using different types of sensors depending on their application. The most commonly used ones include:
1. Bourdon Tube
2. Diaphragm
which will be followed by an explanation of the function and features of these sensors.
Bourdon Tube Pressure Gauges
One end of the tube is closed, while the other end is connected to the fluid whose pressure is to be measured. The process-connected end is designed to remain stationary under pressure, whereas the free end tends to straighten. This movement of the Bourdon tube can be amplified using a gear mechanism and displayed with a pointer to indicate pressure changes.
Diaphragm Pressure Gauges
Pressure Gauge Size
The size of pressure gauges is determined by the diameter of the gauge dial. Standard pressure gauge sizes are measured in millimeters and, according to EN 837, are available in 40, 50, 63, 80, 100, 160, and 250 mm.
Pressure Gauge Accuracy Class
The accuracy class represents the maximum permissible error of a pressure gauge, expressed as a percentage of the full-scale reading. For example, for a pressure gauge with a 10 bar range and an accuracy class of 4, the reading may differ from the actual pressure by 4%. In other words, 4% of the full scale (10 bar) is 0.4 bar, meaning the gauge reading can differ from the true value by ±0.4 bar. The standard accuracy classes and their corresponding permissible errors for manufactured gauges are shown in the table below:
| Pressure Gauge Measurement Accuracy | |
| 0.1 | 0.1% |
| 0.25 | 0.25% |
| 0.6 | 0.6% |
| 1 | 1% |
| 1.6 | 1.6% |
| 2.5 | 2.5% |
| 4 | 4% |
Types of Materials Used in Pressure Gauge Construction
Pressure gauges are used in various processes and for measuring different fluids. Therefore, the material of the gauge must be chemically compatible with both the operating environment and the fluid it contacts. The connection point of the gauge and the dial casing can be made from different materials. For example, if the fluid contacting the gauge is corrosive, the gauge connection should be made of stainless steel. In a similar process where the environment is non-corrosive, a stainless steel body may not be necessary. Considering the process conditions and chemical compatibility is crucial when selecting a suitable gauge, as it can prevent damage to the gauge and, in some cases, avoid additional costs to the system.
The body of pressure gauges can be made from the following materials:
- Carbon Steel
- Cast Iron
- Aluminum
- Brass
- Polypropylene
- رزینی فنولیک
- فولاد ضد زنگ
Common Accessories for Pressure Gauges
- Manifold Valve: As previously mentioned, pressure gauges are used in various industries such as steel, oil, gas, petrochemical, and chemical industries. Naturally, any equipment may require maintenance, repair, or recalibration, and pressure gauges are no exception. Therefore, there are situations where the gauge needs to be isolated from the process line. In such cases, instead of interrupting the entire process, a device called a manifold valve is used to connect or isolate the process line from the pressure gauge. This allows the operator to easily remove, install, or vent the gauge without disrupting the process.
- Diaphragm Seal: This device is used in a wide range of applications, such as high temperatures, corrosive fluids, and more. A diaphragm seal is a flexible membrane that isolates a chamber, allowing pressure to be transmitted while preventing the process fluid from passing through. In many industries, line control without a diaphragm seal is practically impossible.
- Syphon: This device is used to protect the gauge from high-temperature gases. Additionally, a syphon can be used to prevent damage to the pressure gauge when exposed to fluctuating or pulsating fluids.
- Pressure Gauge Snubber: Sometimes, process conditions cause the line pressure to exceed normal levels. In such cases, a pressure gauge snubber is used to protect the pressure gauge from damage.
Pressure Gauge Brands
Isatis Farayand Abzar Company is a supplier of various specialized industrial pressure gauges and the official representative of the Italian brand NouvaFima in Iran.
Nuova Fima is a leading Italian company with over 80 years of experience and 5 branches worldwide, manufacturing industrial equipment such as pressure gauges, electrical pressure transmitters, pressure switches, and diaphragm seals, and holding a significant share of the industrial instrumentation market.
NuovaFima also manufactures thermowells, diaphragm seals, syphons, and various accessories related to pressure and temperature gauges and transmitters.
For more information, you can visit the Nuova Fima website. The catalog of NuovaFima pressure gauge products is provided below:
Isatis Farayand Abzar Company also maintains a stock of various pressure gauge models from reputable brands such as Rosemount, Wika, Nouvafima, and Ashcroft at its Tehran office, available for immediate delivery.
The engineering team at Isatis Farayand Abzar Company is capable of providing consulting services to help select the most suitable model based on operating conditions, environment, and fluid type, as well as to find equivalents for older or sanctioned pressure gauge brands and models for valued customers.
To contact the experts at Isatis Farayand Abzar Company for consultation, supply, or finding equivalents for older brands, You can send an email to: info@isatis-fa.com or call by phone at 88480795 021 or send a fax to 88480798 021 Share your request with the company’s specialists.
