Accutrak Ultrasonic Leak Detector

HVAC technicians know that every air conditioning system leaks. Usually, these leaks are so small that they are not even detectable by advanced equipment. But through regular operation, pressure, and heat taxing the system, these leaks become more substantial, eventually leading to the failure of the system or costly and dangerous inefficiencies. Here is where refrigerant leak detection comes in! The process is simple in concept; use a device or technique to find where the leak is originating and its relative rate. There's no need for a precise number. You want to know if it's a big one or a minor one. Then the repairs are up to your customer or project manager.

Let's have a look at a few leak detection methods and see why an Accutrak Ultrasonic Leak Detector will be the best solution in many situations where other methods fail. A familiar old way is UV dye detection. With this technique you inject a dye into the system which mingles with the leaking refrigerant and can be detected with a UV light. This method is rather clumsy and inaccurate and above all difficult to use in daylight, where many AC units are located. We can set this method aside for the most part in modern applications. The other most common method used is a so-called gas "sniffer". This unit is calibrated to detect the presence of specific refrigerant gases and uses a sensor tip on the end of a gooseneck to pinpoint the source of the leak. While common and somewhat useful, there are some limitations that an ultrasonic detector easily overcomes. Let's talk about how an ultrasonic leak detector works, and then we'll compare how it is superior to a gas "sniffer" in the areas just mentioned.

Ultrasonic simply means a sound that is at a higher frequency than the human ear can detect. Gas and air leaks of any kind produce a kind of hissing noise, but it is at such a high frequency that we can't hear it. An ultrasonic refrigerant leak detector uses a process called "heterodyning," which combines the ultrasonic frequency with another sound frequency that produces a much lower frequency tone that can be heard by the human ear. Also, heterodyning preserves the characteristics of the original ultrasonic noise allowing you to distinguish it from other sounds in the environment. In this way, it is superior to a gas sniffer because, in a windy environment, the sensor-based detector won't be able to detect the gas that the wind blows away. An ultrasonic noise detector will be not be affected however, since the sound is generated right at the source of the leak, wind or no. Another way in which the ultrasonic leak detector beats the sniffer is in the situation of gas saturation. An overactive leak will generate a lot of false positives and make it difficult to pinpoint the leak since refrigerant is all over the place in the environment, overloading the sensitivity of the sniffer meter. Again, an Accutrak leak detector won't have this issue since it's picking up the unique sound frequency coming from the source-point of the leak. A final advantage to any of the ultrasonic HVAC leak detectors made by Superior Signal Company is that they will detect any gas, air, or vacuum leak (not just one or a handful of specific gases) because they are designed to search out that ultrasonic sound we have discussed. Finally, this translates into cost savings, in that there are no sensor tips to continually replace as they degrade when exposed to the gases in question.

There are several great models made by Superior Signal for HVAC applications. The Accutrak VPE is their great entry-level model that comes with either a standard sensing tip or a gooseneck option making it look similar to a sniffer (but remember it's even better!). The Accutrak VPE is a great model for HVAC techs and is very affordable. We will get into other applications for ultrasonic detectors further down this page, but for technicians working in more varied applications, the Accutrak VPE-1000 is a more versatile professional model that will meet all your HVAC needs as well as many other industrial and commercial applications.

An exciting and unique application for the AccuTrak Ultrasonic Detectors, specifically the VPE 1000 and the VPE 2000, is the ability to accurately detect and relatively measure any wear or dysfunction in bearings (and other moving machine parts). Moving parts degrade over time as friction wears on them, and the materials (especially metal) start to break down. Metal pieces, like bearings, that become deformed in turn create increased friction based on their now damaged and irregular shape and wear down further. This wear can damage the motor or machine that they are operating in. All of this can lead to a breakdown of the entire motor or machine, so early detection is critical to avoid downtime and costly repairs. Almost any repair is less expensive when caught early, and routine maintenance based on accurate testing is a must.

A couple of significant advantages to using a Superior Signal Accutrak Ultrasonic detector are that use of these meters requires a lot less specialized training and testing time, compared to vibration meters that are often used for bearing and moving part testing. Perhaps most importantly, an ultrasonic sound detector is excellent with low-speed motors and components that are difficult, or maybe not be possible, to read on a standard vibration meter. An ultrasonic detector can do this because of the process above called "heterodyning". We had a quick look at the technique in the paragraph above but, simply put, heterodyning uses an internal calculation to alter a sound-wave frequency that the human ear cannot hear into one that it can. This process allows you to use an Accutrak VPE to literally listen to the sound of the bearing in the machine (or other moving components). Incidentally, this capability also makes the Accutrak VPE 1000 and VPE 2000 handy meters for determining if bearings are adequately lubricated. As you listen to the sound of the moving bearing, you can make sure that they are moving efficiently without the danger of damage to the machine through over-greasing it.

Now let's have a look at a critical process to understand when testing bearing-containing machinery with an Accutrak ultrasonic detector: setting baselines. Setting baselines is a reasonably straightforward concept, but we'll run through it anyway since it is vital, as ultrasonic readings are relative. Basically we are going to use our ultrasonic meter to establish a level that represents our bearings' or machine's current functioning condition, record this value, and then perform periodic testing with the same settings to see if and how much the components have degraded. The Accutrak VPE 1000 and VPE 2000 both feature a bar graph readout on the device that displays the sound it picks up relative to your sensitivity setting. For this baseline measurement, we want to use the down arrow to adjust the sensitivity low enough that the loudest sound from the bearing does not pass the halfway point on the bar graph. We now record the sound value that the Accutrak VPE gives us on the charts included with the device (these come in the manual, and you want to be sure to scan the chart to print copies in the future). Also, be sure to record the sensitivity setting you used and correlate both it and the sound value with the equipment you are measuring. Next, at a later date in our scheduled maintenance routine, we'll set the same sensitivity settings for the machine we tested (refer to the charts you've made), and see if the sound value has increased beyond the point in the previous measurement. If it has increased, you're detecting bearing wear. More noise = more wear and breakdown. The threshold at which maintenance or repair must take place is up to you or your project manager. Still, ultrasonic sound detection offers a relatively easy and intuitive way to check for the problems we've discussed. Just listen!

Here we'll have a look at another useful application of the incredibly versatile Superior Accutrak Ultrasonic Leak Detectors – testing for leaks on valves and steam traps. A steam trap system is closed, so any leak detection method in which you need to disconnect a component is next to impossible. What we need is a way to find leaks when the system is live and running.

What's the point of testing this? Steam is generally costly to produce and is used in large-scale heating and manufacturing purposes. Now a leak isn't necessarily a hazardous condition like a gas leak. Still, the most considerable advantage in finding these leaks early and accurately is the savings of potentially thousands of dollars in energy costs due to poorly running leaky systems. These undetected leaks have been compared to trying to heat a home with the windows open. You're simply working against yourself. Estimates have put the average leak rate of steam traps in untested plants and buildings at up to 30%! We need a simple and cost-effective way to manage a significant problem like that. Luckily, Accutrak ultrasonic leak detectors offer just that.

Typically these leaks are reflected in a slowly rising power bill. It's easy to let it get of hand when the increases are small and infrequent. However, plant owners and contractors need a solution to stop the problem before it gets too big. Fortunately, specialty tools like the Accutrak VPE 1000 and Accutrak VPE 2000 pay for themselves very quickly when you consider how easy they are to use, allowing technicians to detect these too common and quite expensive leaks with very little training.

The process when working on valves and steam traps is quite similar to what we described previously (above), with a couple of distinctions. The ultrasonic leak detector itself works on the same principle described above: heterodyning. Briefly again, heterodyning allows the meter to "listen" to an ultrasonic noise (created by the leak) that the human ear cannot detect. It mixes this sound with another sound and uses an algorithm to allow the user of the ultrasonic noise detector to "hear" the leak itself. The diagnosis of faulty components can thus be made in seconds. In turn, this makes regular maintenance easy to implement.

Maintenance personnel will, of course, need an understanding of how the particular steam trap system is designed, but the testing process itself is simple. The trap should have a regular cycling operation. If the trap is functioning correctly, you will hear this "open/shut" cycle happening with no anomalies. When a leak is present, there will be a tell-tale rushing sound that will usually be both louder than the typical cycle sound and also will continuously occur even when the trap should be in the "shut" portion of the cycle. Again, this is actually easier to hear for yourself than to explain. It is very intuitive.

One of the distinctions mentioned above is that testing for steam trap and valve leaks is best done with the use of the included touch probe. This long metal piece attaches to the top of the unit and makes hyper-precise testing of an area a snap. You just touch the probe tip to the trap or valve and listen with your ultrasonic detector.

One final point in this section is the testing of water valves. The procedure is the same, but something to consider is that leak detection will be best with the valve fully tightened. This is because, with the valve open, there is less turbulence. When closed, a leaking valve will produce a good deal of turbulence, which will be audible to your Accutrak Ultrasonic detector.