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When working with hydraulic tools, a hydraulic pressure gauge is an essential component of the system that must be monitored and checked. Users often overlook this component and may unwittingly expose themselves and the entire hydraulic system to damage.

Why use a hydraulic pressure gauge?

A hydraulic pressure gauge is used to measure the pressure of hydraulic fluids in hydraulic systems. It is a tool that allows you to monitor and control pressure, which is extremely important for safe and efficient operation. Hydraulic pressure gauges can be used in various situations, such as:

• lifting loads, 

• detecting leaks and blockages, 
• troubleshooting system pressure issues.

Pressure gauges come in many varieties, so you’ll find:

• dry-gauge, 

• digital, 

• glycerin-filled.

Why use a hydraulic pressure gauge?

Working without a hydraulic pressure gauge is unpredictable. You might not notice, for example, a sudden drop or rise in pressure. When you monitor the pressure gauge, you have insight into the system. If a problem arises, the device will show it. That’s why it’s essential for safely performing checks, such as inspecting connections or hoses. What’s more, with a pressure gauge, you can effectively troubleshoot issues. Imagine you’re using hydraulic jacks to lift a load, but the load won’t lift. The pressure gauge can indicate whether the pump is generating sufficient pressure and operating correctly. If so, you know the problem lies elsewhere—for example, the cylinder might be too weak.  With a pressure gauge, you can detect leaks and blockages. How? If there are leaks or blockages in the circuit, the pressure in the system will drop, and you’ll see this on the pressure gauge. Technicians can then identify the cause of the pressure drop and fix it immediately. You’ll also prevent hazards such as:

• exploding hoses, 

• hydraulic fluid leaks,

• load drops.

What should you consider when choosing a pressure gauge?

You already know that there are two types of pressure gauges:

• dry, 

• digital, 

• glycerin-filled.

But what should you consider when choosing a pressure gauge? When selecting a pressure gauge, several key factors must be considered to ensure accurate pressure measurement and trouble-free operation in a given application. First and foremost, the pressure gauge’s measurement range should be selected so that the measured pressure does not exceed 75% of its maximum measurement range. Another important aspect is the type of medium being measured—liquid or gas—for which the appropriate type of pressure gauge must be selected. Mechanical pressure gauges are cheaper and do not require a power source, but they are less accurate than electronic ones. The material of the pressure gauge, such as stainless steel, brass, or plastic, depends on the application’s requirements, e.g., corrosion resistance. The diameter of the pressure gauge face should also be tailored to the needs, as pressure gauges come in various sizes. It is also important to consider operating conditions, such as resistance to vibration and high temperatures above 60°C at the measurement site. It is best to install pressure gauges vertically, in accordance with their calibration, or to calibrate them in their final position to ensure accuracy. The pressure gauge’s accuracy class affects measurement precision—the higher the class, the more accurate the measurement, but also the higher the price of the device.

Why use a glycerin-filled pressure gauge?

The glycerin inside the pressure gauge dampens the effects of sudden pressure changes. This helps protect the mechanisms inside the gauge. These types of pressure gauges are ideal for applications where system loads and sudden pressure changes may occur. A glycerin-filled pressure gauge should also be used with pumps, as glycerin dampens vibrations, improving readability and extending the gauge’s service life.

What to consider?

Make sure the pressure gauge is rated for the pressure you’re working with. For example, a reading of 25 bar on a gauge with a 1000-bar range won’t be very accurate. Additionally, a gauge designed for a lower pressure than your application is likely to fail.

• Pressure and force: Some pressure gauges have a scale that displays both force and pressure. For example, a force gauge can measure the load supported by a jack.
• Scales: Available in imperial and metric versions. Required accuracy: +/- 1.5%, though +/- 0.25% can be achieved with a digital pressure gauge.
• Material selection: Copper alloy is common for lower pressures. Stainless steel is often used for high pressures. It’s worth checking if the material will be suitable if you’ll be working in harsh conditions.
• Mounting options: pressure gauges are most often mounted using a thread. Make sure you choose a pressure gauge with the correct thread for the mounting, e.g., ½ or ¼.

How to safely connect a hydraulic pressure gauge?

To properly install a hydraulic pressure gauge, follow these steps:

• Selecting the right installation location: The pressure gauge should be installed in a place where it is easily readable but also well-protected against mechanical damage and vibrations. This is usually near a pump or another component of the hydraulic system.
• Preparing the installation: Make sure that pipes, hoses, and connections are clean and free of contaminants.
• Pressure gauge installation: The pressure gauge should be mounted on a rigid section of pipe to minimize the impact of vibrations on measurement accuracy.
• Use appropriate gaskets of the correct diameter to ensure the connections are tight.
• Connecting the pressure gauge: Connect the pressure gauge using appropriate adapters and fittings that match the threads in the hydraulic system. Adapters allow for a secure connection of the pressure gauge to the system.
• Use a high-quality thread sealant on the male threads of the fittings: if using Teflon tape, apply it sparingly and do not wrap it around the first thread to avoid contaminating the system.
• Testing and calibration: After installing the pressure gauge, test the system to ensure that the gauge is functioning properly and there are no leaks. The pressure gauge should be operated at pressures that normally do not exceed 75% of full scale to ensure its long service life.
• Additional accessories: Depending on your needs, you can install additional accessories, such as damping valves or shut-off valves, which help protect the pressure gauge from sudden pressure changes and vibrations.

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