Detecting Vacuum Pump Leaks

So you read our first blog, “What is a vacuum leak?” and now you’re worried that your vacuum pump may have a leak? No problem! Vacuum pump leaks can develop out of the blue or slowly over time for a variety of reasons. It can simply be from normal wear and tear or introduced after maintenance or repair. Luckily there is an array of methods you can use for detecting a vacuum pump leak in your system, and we’re going to discuss the most effective and efficient ways for finding the source.

In this blog we’ll be going over:

  1. Different tools used for detecting vacuum pump leaks.
  2. Basic methods used for vacuum pump leak detection.
  3. Where to find the necessary tools you’ll need.

Different Tools Used For Detecting Vacuum Pump Leaks

Like any project, accomplishing your task efficiently and successfully is made possible by having the right tools. The most common tools used for leak detection (depending on your systems requirements) are:

  • Helium Leak Detectors
  • Ultrasonic Leak Detectors
  • Portable, Compact, or Stationary Detector Units

Another tool that we like to recommend to our clients is patience, however, this can be a little harder to find sometimes but can make a big difference.

Basic Methods Used For Vacuum Pump Leak Detection

Some more basic methods for vacuum pump leak detection include:

  • The solvent method
  • Bubble testing
  • Masking
  • Dye Penetration
  • Pressure Rise

The first thing we want to do is check the obvious places. As we mentioned in our previous blog, common areas to check include o-ring applications, areas with welds, turned parts, and bolts placed in blind holes. Another one of the first places you’ll want to check is the last area on the system that was worked on or modified. These first steps can end up saving you a lot of time and stress.

A Helium leak detector is a mass spectrometer tuned to detect helium gas, and through the process a leak rate is determined based on the amount of helium collected. Because helium is a very small molecule, it has the ability to find its way through any small openings that may be on the system. Helium leak detectors are highly accurate and good for finding very small or micro sized holes, especially in hard-to-reach places.

An Ultrasonic leak detector is used to detect vapor or gas leaks in areas where they cannot be seen, heard, or smelled by a person. They work by detecting vibrations made in the air by small leaks under pressure and convert them into an audible hissing or alarm that can then be heard by the operator. The device is used simply by pointing it in the direction of the suspected leak and the converted sound is heard through headphones. What is nice about these devices is that they are handheld and easily transported.

As far as making the decision between portable, compact, or stationary devices goes, that is left up to you and the type of system you are investigating. Portable detectors are used best for on-site leak detections when traveling between different locations. Compact detectors are used primarily for stationary devices in commercial industries, but are portable with special carts made for transportation. Stationary or high-performance detectors are used for large-scale testing or extremely sensitive vacuums used in medical technology or research and development.

There are also the more basic testing methods that may suit your needs and won’t be as costly as a machine, however, you will lose the benefits of getting extra data information from your system.

The solvent method is effective for locating vacuum pump leaks that would be larger in size. A solvent like acetone or alcohol, acetone being preferred, can be sprayed on the suspected area and when it enters the system you will see a sudden spike in pressure on the vacuum gauge.

Bubble testing can be applied two ways. The first being a dunk method which can only be used to detect leaks within removable components. Warning! Never submerge the entire pump! Rub a soap detergent on the suspected area and then submerge it in water. You will be able to see any bubbles being made from escaping gas. A simpler version of this is to just spray the area with a soap solution and watch for bubbles forming from escaping gases. Obviously the more bubbles being produced, the bigger the leak. This method is not effective for finding small leaks.

Masking refers to the application of a masking compound placed on the system and moved around until a fall in pressure is observed. You have then found your leak. This method can also function as a temporary fix, but again, to avoid any further damage a permanent repair should be implemented as soon as possible.

Dye Penetration is when a dye of some sort is painted on the surfaces of a suspected leak. After some time, the fluid will penetrate the otherwise impermeable material in the place of the leak.

Pressure rise is the most simple method. However, with this method you will only be able to detect that there is a leak present, not where the leak is located. Just use your system gauge to determine if your system pressure reads something other than what you would normally expect.

Where To Find The Necessary Tool You’ll Need

Tools and repair kits can be found on or through our website from a variety of brands and manufacturers. Helium leak detectors and ultrasonic detectors can be found on a variety of sites and manufacturers simply through a google search. We will have links at the end of this blog where you can find these devices.

In our next blog, we’ll be discussing how to repair your vacuum pump leaks. Be sure to visit our online store for more information or to find thousands of parts and products for your vacuum pumps.

Thank you for choosing Precision Plus! This is Pete signing out till next time!

Precision Pete's signature mark


Find Helium Leak Detectors

Rent Helium Leak Detectors

Find Ultrasonic Leak Detectors

This Post Has One Comment

  1. Pingback: Repairing Vacuum Pump Leaks - Precision Plus Blog

Leave a Reply

Your email address will not be published. Required fields are marked *