Compressed air leak

An air leak is considered to be the consumption of compressed air without performing any work by the compressors. If this is not controlled, the excess consumption of compressed air can exceed 25-50% of the total equipment capacity (with a corresponding increase in financial costs). Therefore, production always monitors the proper operation of pneumatic equipment and implements measures to detect, eliminate, and prevent leaks.

Why are leaks dangerous for the enterprise?

Compressed air is one of the main energy carriers in industrial enterprises. Leaks of compressed air through various structural defects lead to excess consumption of energy carriers, which negatively affects the overall financial situation, and also:

• Reduce the efficiency of pneumatic tools and equipment with pneumatic drives;
• Lead to excess electricity consumption due to the compressor equipment regularly consuming more power;
• Shorten the service life of compressors and reduce the intervals between repairs of this equipment, since it is forced to operate under constant high load, in a continuous cycle (resulting in additional maintenance costs);
• Can cause injuries.

Situations may also arise where there is a false impression of insufficient existing capacity, and a decision is made to purchase and commission new compressor equipment. Such a decision is always costly but not always justified, since the drop in capacity may actually be related to air leaks.

Why do leaks occur?

Among the most common causes are the loss of tightness in welded and soldered seams, threaded and flanged connections, pressure regulators, faults in condensate drains, shut-off and solenoid valves, damage to hoses and pipelines. Also, the cause can be unopened shut-off valves and air-consuming equipment left on unnecessarily. When checking for air leaks, all these causes are analyzed.

Economic losses from compressed air leaks

Leak points are like nozzles through which compressed air continuously escapes into the atmosphere without performing useful work. Even through a 1 mm diameter hole, 75 liters of compressed air will escape per minute (assuming the working pressure in the network is 8 bar), which corresponds to energy losses of 0.6 kW per hour.

If the hole diameter is 5 mm, the leak will be 1700 liters per minute, which equals 13.2 kW. Knowing the operating time of the equipment and the price of energy carriers, it is easy to understand that losses will be quite significant even if there is only one leak in the pneumatic system. In practice, there are many, and the financial losses of the enterprise due to excess energy consumption become enormous. That is why it is so important to find air leaks in a timely manner.

What level of leaks is considered acceptable?

Complete elimination of leaks in pneumatic equipment is not always possible. Often, measures to completely eliminate excess compressed air consumption cost production significantly more than "planned losses." Therefore, there are "acceptable leaks" for different compressor networks, including:

• Losses up to 15% of the total volume of consumed compressed air are allowed at large metallurgical enterprises;
• Up to 10% - in large compressor networks;
• Up to 7% - in medium-sized ones;
• Up to 5% - in small ones.

However, the existence of such recommendations does not mean that the condition of compressors and pipelines should not be monitored. Timely detected damage will help avoid increased losses and, consequently, costly reconstruction. Let's explain how air leak detection is carried out and what equipment is necessary to perform the inspection.

Main methods of detecting air leaks

Large leaks are often noticed by sound. However, medium and especially small network damages are much harder to identify. How to check for air leaks? The following methods are used:

• Visual inspection of the pipeline (this can reveal significant damage or unopened valves, "leaking" connecting elements).
• Using special aerosol foam. It is applied to the surface and forms bubbles when compressed air passes through. Sometimes soapy water is used for this purpose.
• Using a flow meter. Such devices allow measuring the air production level when compressors are off, and therefore are widely used for monitoring purposes. If there is a shut-off valve between the compressor and the system, and a pressure gauge is installed after it, the volume of leaks can be estimated by the formula Leaks (m³/min) = system volume (m³) • (P1 (bar) – P2 (bar)) • 1.25/t (min), where 1.25 is a correction factor, P1 is the working pressure, P2 is the pressure after closing the valve, T is the time during which the pressure dropped. This calculation method is good for detecting leaks in principle and estimating their volume. However, it, firstly, requires stopping the equipment, and secondly, does not allow locating the leak points.
• Using an ultrasonic leak detector or air leak sensor. This equipment is capable of detecting even small leaks, as it detects characteristic sound waves in the ultrasonic range and transmits information to the operator. It works even against the background of industrial noise and does not require stopping or restarting production.

Leak detection and implementation of measures to eliminate them should be carried out regularly. As a rule, comprehensive system monitoring twice a year is sufficient to avoid significant financial losses. After implementing a leak detection and elimination system, compressed air production costs can be reduced by 25-30%.

Ultrasonic Method for Detecting Compressed Air Leaks

This is the most modern and advanced method. It involves the use of ultrasonic acoustic leak detectors that allow detecting the slightest leak points. With this equipment, pipelines can be inspected even from a distance, including all hard-to-reach areas and connections.

Ultrasonic Leak Detectors

The ultrasonic compressed air leak detector operates on the following principle: it captures signals in the ultrasonic range that are generated when compressed air passes through a small-diameter hole into a low-pressure area. The signal is converted and transmitted to headphones and a display, thus forming audio and visual alerts. The latest models of such devices not only allow quick leak detection but also help estimate approximate losses from such leaks. They are used to detect defects and depressurized areas in pipes, joints, valves, cylinders, tanks, and pressure vessels.

These are handheld tools, and the operator with such control equipment can be located up to 6 meters away from the pipeline or other system elements. The ultrasonic leak detector quickly detects leaks of any size (the device sensitivity can be adjusted). The kit also includes special attachments (in the form of a tube and a parabolic reflector) that improve leak detection quality and allow highly accurate localization of the leak even near operating equipment with moving parts. The device demonstrates stable operation in conditions of high noise pollution, strong wind, and dusty environments.

"Izmerkon" offers popular models of ultrasonic leak detectors, such as LD 450 with a focusing attachment and acoustic tube (allows localization and detection of leaks even in hard-to-reach places at a distance of several meters) and LD 500/510 as a more modern model with a camera and loss calculation function. The devices can be equipped with an ultrasonic generator that allows detecting leaks even in systems without pressure. Such equipment is used for regular monitoring of pneumatic networks and helps enterprises save hundreds of thousands of rubles annually.