Pressure Gauge Maintenance, Functions, and Types
To prevent potential hazards and ensure the efficiency of a pipe system, pressure gauges are used in both industrial and residential systems. And, as they play a vital role, pressure gauge maintenance must be done properly. They also come in a wide array of designs and materials to suit the function and condition of each system.
So, in this article, we will explore the function, types and categories, and maintenance of pressure gauges to help you make any piping networks safer and more efficient. At the end, we will answer some of the FAQs about pressure gauge maintenance.
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Importance of Pressure Gauges in a Pipe System
Piping networks are intricate and play a crucial role in various industries as well as residential plumbing systems. Using the right instrumentations in a network can guarantee its safety, efficiency, and longevity. Pressure gauges are among the most vital process instruments that measure the pressure within a system.
There are different types of pressure gauges based on how they measure the pressure level. In addition, they serve multiple important functions that will be discussed below.
How Do Pressure Gauges Work? Types of Pressure Gauges Based on Mechanism
The main use of pressure gauges is to measure the force exerted by the fluid on a sensor in a pipe system. Based on how they accomplish this function, they fall into three common categories.
- Bourdon gauges
- Diaphragm gauges
- Digital gauges
Let’s go over their mechanisms one by one.
Bourdon Tube Pressure Gauge
Bourdon pressure gauge is a simple and common tool to indicate the pressure of a gas or liquid. It includes a curved elastic metal tube that is connected to the gauge. One end is connected to a fluid input and the other end of the tube is sealed which is attached to a lever. Therefore, when the fluid enters the Bourdon tube, it straightens and causes the lever to go up. How much this lever is pulled up depends on the amount of pressure.
This lever is also connected to a needle which converts the movement of the lever to the pressure reading on the gauge dial. This pressure is reported in different pressure units, such as psi, Sl, and bar.
One important consideration in using Bourdon tube pressure gauges in a pipe system is to make sure the Bourdon tube metal is compatible with the fluid. The most common metals used are copper and brass which can react to certain chemicals. In order to reduce the risk of reactivity, stainless steel can be a better choice.
What’s more, due to its direct mechanism, Bourdon gauges are not the most accurate pressure gauges but they have been used effectively since the mid-19th century and their mechanism has remained the same over the years. However, there have been some improvements. For example, some Bourdon pressure gauges use digital displays to make the reading easier.
Diaphragm Pressure Gauge
For a more precise measurement, a kind of thin circular elastic diaphragm, made of metal or elastomer, is inserted between the fluid and the Bourdon tube. In other words, one end is in contact with the gas or liquid, and the other end is kept at a reference pressure. The reference pressure can be vacuum, atmospheric pressure, or any other pre-set pressure. As the pressure of the fluid increases, the diaphragm deflects proportionately. The deflection then is converted to the pressure reading.
This indirect mechanism is more precise because the diaphragm provides a larger surface area that is exposed to the fluid. So, even minor changes in the pressure can be displayed on the gauge face.
Aside from the accuracy, the diaphragm increases the pressure gauge’s longevity as the fluid does not come in direct contact with the Bourdon tube. Especially, if the fluid contains particles that can accumulate inside the tube over time and lead to even less precision in simple Bourdon tube pressure gauges.
However, like Bourdon gauges, you should also consider the material of the diaphragm gauge. The diaphragm is usually made of stainless steel to reduce the risk of reactivity and corrosion. Also, some elastomers, such as silicon or rubber, are commonly used in making the diaphragm. But one perfect solution to ensure there would be virtually no reactivity with the fluid is to use a gold or Teflon coating on the diaphragm.
Digital Pressure Gauge
Digital pressure gauges use the same diaphragm mechanism but the diaphragm is attached to strain gauges (also called force-sensing resistors) or piezoelectric elements (piezometer pressure gauge). As the pressure changes the resistance of the electrical circuit changes as well. Therefore, to show the pressure, the current of the circuit is measured and converted to the pressure reading. The pressure is then displayed on a digital screen.
In addition to the increased accuracy and simpler reading, digital pressure gauges offer some other features that can result in more precision and efficiency. For example, you can customize the units or access data logging to keep track of pressure changes over time.
To sum up, there are two main mechanisms used in these pressure gauges, the direct mechanism (Bourdon gauges) and the indirect mechanism (diaphragm and digital gauges). Additionally, there are other less common types of pressure gauges with specific designs and configurations that make them suitable for certain environments and applications. However, regardless of the type of the instrument, to ensure its precision and safety of the system, it must be connected and maintained accurately and appropriately.
What Are the Functions of Pressure Gauges?
Before we start our important discussion of pressure gauge maintenance, it is good to know more about pressure gauge uses in a piping network. Here are some of their chief functions.
Operators or homeowners can instantly access real-time information about the pressure of the fluid in a specific part of the system. This helps them to ensure the pressure levels are within their desired range and that the system’s performance is optimal.
Diagnosing Potential Issues
Any sudden drastic changes in pressure levels indicate issues, like leakage, blockage, malfunctions of other instruments and parts of the system, and the pressure-regulating devices. Keeping track of the pressure changes can help you identify regular patterns that lead to problems.
Monitoring System’s Safety
Over-pressurization is a dangerous consequence of not using appropriate pressure gauges in a pipe network. It can lead to bursts and damage to the appliances. So, perhaps their most crucial function is to help keep the pressure levels within a safe range.
Help in Maintenance and Troubleshooting
Sometimes, when experts need to find issues or to check for any potential problem, they use pressure gauges to read the pressure levels at different locations of the system. They can compare these readings to some baseline values and standards to diagnose issues, and imbalances, or to make sure the system is working smoothly.
Process Control in Industrial Pipe Systems
In many industrial pipe systems, maintaining consistent pressure levels is necessary for some manufacturing processes and operations. Pressure gauges can monitor and adjust the pressure levels with precision that is required for an efficient and reliable operation.
However, pressure gauges ensure the system’s safety, efficiency, and longevity only if they are suitable for the system and its applications, installed properly, and maintained appropriately.
Pressure Gauges Maintenance Considerations
As faulty pressure gauges can lead to injuries and irrecoverable damage, following the guidelines below is of utmost importance.
Regular Calibration Is a Necessity
Have a schedule to calibrate pressure gauges regularly to make sure of their accuracy. The frequency of pressure gauge calibration should be determined according to its type, the condition of the system, the application, and the manufacturer’s recommendation. In addition, the calibration must be done by a qualified technician.
Inspect for Damage
Regularly check pressure gauges for physical damage, such as cracks or corrosion. Also, make sure that the gauge dial is accurate and the pointer is aligned. Even a little issue must be addressed immediately. Additionally, periodical pipe system inspection to detect imbalances, leaks, blockage, and other anomalies is essential. Any such issues can affect the performance of pressure gauges and cause damage.
Adjust the Zero Point
If the gauges have the zero adjustment feature, you should consider it in your pressure gauges maintenance routine. This is necessary for their precision. You should follow the manufacturer’s instructions to adjust the zero point.
Protect the Gauges from Environmental Factors
Pressure gauges are affected by excessive heat, moisture, cold, sunlight, and extreme fluctuations in temperature. So, you should take measures to shield them from these environmental factors. For example, you can use protective covers or enclosures.
Each type of pressure gauge can handle a specific pressure range. If the pressure exceeds the gauge’s limit, failure and inaccuracy are unavoidable. Therefore, installing pressure relief devices, like pressure relief valves, is recommended to protect the gauge from overpressurization.
The pressure gauges must be connected, mounted, and installed properly. For example, you should make sure fittings, adapters, and other instrumentations are appropriate and securely connected to avoid malfunction or leakage. Besides, any excessive torque and tightening result in internal damage and inaccuracy. So, proper installation requires hiring an experienced technician and following the manufacturer’s instructions.
Keep a Record of Pressure Gauges Maintenance Activities
To be able to track the history of the pressure gauges and their issues, identify patterns and trends, and plan future replacements and upkeep, you should record the problems and maintenance activities properly.
Besides adhering to these general pressure gauge maintenance tips, every type, model, and system has its own maintenance requirements that must be followed. Consulting with an expert and the manufacturer’s guidelines can help you ensure the safety, reliability, and durability of the pressure gauges and the whole piping system.
FAQs about Pressure Gauges Maintenance
We have already covered the main concerns about pressure gauge maintenance. Still, we will briefly answer some of our clients’ most common questions.
How Often Should I Calibrate Pressure Gauges?
The frequency of pressure gauges calibration depends on factors, such as the type, material, system’s conditions and requirements, environmental factors, etc. So, consult with a qualified technician and follow the manufacturer’s instructions.
Are Pressure Gauges and Pressure Safety Devices the Same?
No. Pressure gauges measure the level of pressure while pressure safety devices ensure the pressure stays within a safe limit.
How Accurate Are Pressure Gauges?
The gauge type, calibration, and quality all affect the precision of the pressure readings. Most typical pressure gauges in good conditions offer 1% through 2% full-scale reading accuracies. However, more sensitive gauges are available that offer 0.5% or even better accuracies.
Can Pressure Gauges Be Repaired?
Some faults and damage can be repaired, for example, misalignment of the pointer. But in more severe cases, the pressure gauge must be replaced to ensure safety and precision.
Can Pressure Gauges Measure the Pressure of Both Gas and Liquid?
Yes. Pressure gauges can measure the pressure of different fluids. However, you should consider the fluid when choosing the pressure gauge type and material.
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Let Us Deal with All of Your Pressure Gauges Needs
We tried to shed some light on pressure gauge maintenance and the significant role it plays in the well-being of a pipe system. Now, you know why it is crucial to choose the right instruments, install them properly, and inspect them regularly.
Process Valve and Instruments in Birmingham, Alabama, can assist you in finding the best product without you leaving your home or office. And, if the existing process instrumentations do not fit your system, our experienced experts tailor specific ones just for your system’s requirements. We also ship them to your place as soon as possible if you are in the US.
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