Gauge cleaning is the process of removing dirt and debris from the surface of a gauge, as well as oiling and lubricating it to prevent corrosion and ensure proper functioning.
A gauge is the most critical component of a pressurized vessel, as it gives the observer an accurate reading of the amount of pressure of the fluid in the vessel at all times. This not only helps the observer ensure that the pressure is at optimal levels for various industrial applications, but it also helps prevent disaster by showing them if the pressure gets too high or too low.
To ensure that the reading of the gauge is always as accurate as possible, it must be regularly cleaned to dispel dirt, oil, and other environmental grime. Another reason for gauge cleaning is that a clean gauge lasts longer than a dirty one, which saves the company that is using it both time and money.
But the gauge cleaning process is not as simple as it sounds. There are different types of gauges, and each one must be cleaned a certain way to achieve maximum sanitation without ruining the device.
In this article, we will explain the precision cleaning processes that Precision Fabricating and Cleaning (PFC) uses to clean pressure gauges, specifically gauge bourdon tubes.
Why Do Gauges Need Cleaning?
The primary reason that gauges need cleaning is to maintain both the visibility and the functionality of the gauge.
As time passes, the interior and exterior of the gauge will naturally become coated with dirt, dust, oil, and other types of grime. If it is allowed to build up too long, this layer of debris can make it difficult for an observer to read the gauge’s analog indicator. It can also hamper the gauge’s ability to obtain an accurate pressure reading. Either case presents a serious safety issue for the observer and anyone else who works in the vicinity of the pressurized vessel.
Another reason for gauge cleaning is to preserve their longevity. A dirty gauge is more likely to break down faster than a clean one. By regularly cleaning gauges, companies can save money on new gauges as well as the time it takes to install them.
What Are The Most Common Types Of Pressure Gauges?
The two most common pressure gauges used in industrial applications are the bourdon tube gauge and gauges with diaphragms/bellows.
What Is A Bourdon Tube Gauge?
The bourdon tube gauge, invented circa 1850, is one of the most widely used instruments for measuring the pressure of liquids and gases of all kinds, including steam, water, and air.
The device consists of a tube coiled into a circular arc. One end is soldered to a central block and is open to the fluid whose pressure is to be measured, while the other end is sealed and coupled to the pointer spindle. When the pressure inside the tube is greater than the outside pressure, the tube tends to straighten, thus turning the pointer. The observer can then take a reading from the gauge’s analog face.
Some bourdon tubes (typically Heise) are constructed with a bleed port to allow flow-through cleaning. Bourdon tubes without a bleed port are called dead end gauges.
What Are Gauges With Diaphragms/Bellows?
Bellow-type gauges are used for the measurement of absolute and differential pressure. They are more sensitive than bourdon tube gauges.
Like bourdon tubes, metal bellows and diaphragms are used as pressure-sensing elements. Because of their large deflections for small pressure changes, bellows gauges are particularly suitable for measuring pressures below atmospheric. Diaphragm gauges, which consist of two corrugated diaphragms sealed at their edges to form a capsule, are best used in aneroid barometers to measure atmospheric pressure.
What Are The Gauge Cleaning Processes?
There are three methods that can be used to clean a bourdon tube gauge. The specific method that is chosen to clean a given bourdon tube depends greatly on how dirty the gauge is and the level of cleanliness that must be reached. It also depends on whether or not the bourdon tube is equipped with a bleed port.
The first gauge cleaning process we’re going to discuss is for bourdon tube gauges with a bleed port, while the second and third methods are for gauges that have dead ends.
1. Gauge Cleaning Process For Gauge Bourdon Tube With Flow-Through Method
To start this process, the small Allen set screw or acorn nut is removed from the end of the bourdon tube.
Next, the approved test solvent is made to flow through the bourdon tube, after which we collect a sample amount that is a minimum of 100 ml. We then calculate the sample results on the basis of one square foot.
The solvent in the beaker is transferred to the lab for processing in accordance with laboratory procedures for particulate and NVR analysis. A maximum of one gauge is allowed per sample. This step is done to ensure that the cleaning process was completed properly.
2. Gauge Cleaning Dead-End Gauges Using Vacuum Chamber Process
To gauge clean a dead-end bourdon tube using a vacuum chamber process, we first place the gauge in the vacuum chamber with the inlet port of the gauge immersed in a beaker containing the approved test solvent.
Cleaning and sampling are accomplished by evacuating and venting the vacuum chamber a minimum of ten times. The vacuum allows the solvent to be drawn up and into the bourdon tube and then released back into the beaker when the vacuum is vented.
3. Cleaning Dead-End Gauges Using Fill And Drain Process
Finally, to clean a dead-end gauge bourdon tube with the fill and rain process, the inlet port of the bourdon tube is flushed with the approved solvent by using an eye dropper or a syringe to fill and then drain the tube. This process is repeated as many times as necessary until the desired cleanliness level is met.
PFC Offers Expert Gauge Cleaning For Industrial Applications
Your pressure gauge needs expert, precision cleaning, so that it can maintain optimal functionality and longevity. Precision Fabrication and Cleaning (PFC) provides that gauge cleaning expertise. Contact us today to discuss your gauge cleaning needs and how our services can help.