SJ Blog
How to buy a pressure gauge?
Are you looking to buy pressure gauges but don't know how to choose the right one for you?
After only five minutes with this presentation, you will better understand pressure gauges to make a more informed decision.
1. Dial Size:
The most important factor in choosing the right size is how far observers will be from the gauge. The farther an observer, the bigger the display needs to be. Selecting the correct size is important for any observer to conveniently read the gauge.
Common dial sizes are:
• 1 ½" (40mm)
• 2" (50mm)
• 2 ½" (63mm)
• 3" (75mm)
• 4" (100mm)
• 6"(150mm)
• 8"(200mm)
• 10"(250mm)
※Accuracy also Affects the Choice of Dial Size
2. Scale Range:
In order to ensure safety during measurement and to extend the service life of the pressure gauge, select a dial that puts the average pressure between 25% and 75% of the dial scale (as shown in the figure below). For example, when the average pressure commonly falls between 2.5kg/cm2 and 7.5kg/cm2 during use, it is recommended to buy a pressure gauge with a scale range of 0kg/cm2 to 10kg/cm2. It will be hard to observe if the low pressure range (the yellow area in the figure below) is too large, and there will be a risk of overpressure, or even burst pressure, if the high pressure range (the red area) is too small.
※Commonly Used Units are bar, psi, MPa, kgf/cm2 (Often Referred to as kg or kg/cm2)
3. Case:
| Material | Characteristic |
| black painted -iron |
• More economical |
| Stainless Steel |
• Resistance to corrosion, weak acids, alkali and water |
| Phenolic | • Commonly used in environments at risk of sea breeze erosion |
4. Liquid or No Liquid:
Liquid-filled pressure gauges are most suitable when equipment is not stable or vibrates during operation. The liquid can prevent the pointer from affecting the observation and can also lubricate the dial gear to extend its life. Glycerin is the most common liquid used in the pressure gauges, but may be silicone under specific conditions. If you are not facing any of these problems, use a standard gauge without liquid to Avoid Leakage.
5. Mounting Styles:
The pressure gauge can be divided into two types: Lower mount (also called “bottom mount”) and back mount.
6. Connection Size:
The diameter of a connection thread can be measured with a vernier caliper (the tool shown in the figure). Connections can be divided into straight (parallel) threads and tapered threads. See The Introduction and Selection of Common Connection Specifications for more details.
7. Wetted Part:
The blue area in the figure on the left is the wetted part of the pressure gauge. Common materials are brass and stainless steel. Brass material is more economical, but it can't resist corrosion, acids or alkalis — only stainless steel 304 or 316 can. When the thing being measured is thick, highly corrosive or contains many impurities, it's recommended to use a Diaphragm Seals.
For more information about the corrosion of materials:
The Degree of Corrosion Resistance of the "PP Connection" Pressure Gauge
We hope you now have a basic understanding when it comes to choosing a pressure gauge. Do you want to know how to install and maintain it to extend the service life? Or how to solve pressure gauge failure? Click the links below to learn more!
- Common Problems Affecting the Life of Pressure Gauges and How to Solve Them
- Installation Precautions and Installation Steps for Thermometers and Pressure Gauges
Be the first to know about SJ Gauge's latest news and updates!
►Related Product：
|
|
|
|
