Leak Test

These pages are full of information regarding air leak testers.
Air leak testers are introduced from many angles. Please see the page you require.

Cosmo Air Leak Testers: Supporting the Manufacture of High-Quality Products

Expansion to International Markets

In recent years, Japanese corporations are increasingly shifting to overseas production. The same quality of craftsmanship which is required in Japan is also required internationally, and the number of leak testers being used internationally is also increasing.
Cosmo Instruments has been setting up bases overseas, with representative offices in the U.S.A. and Korea and a representative in Taiwan set up in the 1980s.Bases are now in twelve countries, including China, countries of Southeast Asia, and India.
Most of these countries are already equipped with a system for providing the same level of quality service as Japan with staff specializing in leak testing.
We will continue to make efforts so that leak testers can be used with peace of mind in all countries.

What is Required of a Leak Tester

Cosmo Takes Responsibility for Leak Tests

A leak tester is built on technology which can accurately detect slight changes in pressure due to leaks, but that is not all that is required.
Technology which can find causes of pressure change other than leaks and minimize their effects is also necessary.
Many of those causes are due to the testing environment, such as the clamp sealing fitting of WORK, the pipe fixture, or the ambient temperature.
At times, WORK itself could be harboring the problem, such as warping, temperature changes, or interior leaks.
Technology to comprehensively analyze and handle these is the air leak testing technology required of us manufacturers.
We at Cosmo Instruments promise our customers, in our role to supply this technology, to be responsible to the end for leak testing.

We will meet your requirement for high reliability.

Reliability is what is most required of leak testers, and we believe that Cosmo Instruments taking responsibility for leak tests results in trust from the customer.For this reason, we at Cosmo Instruments provide products providing peace of mind to our customers under any use environment and technical support to make full use of them correctly.

The Differential Pressure Sensor at its Core is Highly Resistant to Differential Pressure and Highly Sensitive in Performance

Cosmo Air Leak Testers are equipped with a Differential Pressure Sensor (DPS) with a high sensitivity of 0.1 Pa and a high resistance to differential pressure of 5MPa.
This is standard equipment, and achieves high measurement reproducibility and leak sensitivity due to the intelligent air circuit, including an independently developed air valve.
For every leak test, the DPS bears a heavy load of several million times the differential pressure of the leak.The DPS developed by Cosmo can be used over 10,000,000 times at the maximum working pressure without a change in its sensitivity.
Currently, we have solved various problems and provide leak testers which can be used at test pressures up to 16MPa.

The Mastering Feature Which Changed the Concept of the MASTER Comparison Method

The patented mastering feature which comes standard is a feature which automatically compensates for the effect of adiabatic compression which occurs due to air pressurization.
The leak-free MASTER of the same model as WORK, which had been used for this purpose in contemporary setups, can be replaced by the standard MASTER chamber.
The time required for stabilization of added pressure is shortened, and the setup is capable of a high level of detection with a short time required for measurement.Adjustments for leak tests also become simpler, so man-hours required for setup can be reduced.
It can be said that the contemporary concept of the MASTER comparison method has changed.

Proved Superior Durability and Less Failures

The second most important point for inline testers is that they are durable, without failures.
Failures halting production lines and troubles stemming from misjudgments cause large losses.
Frequent breakdowns would also require backup parts.
Leak testers made by Cosmo Instruments have the greatest history of use in Japan, and have been proved to be durable, with low frequencies of failures. We are rated highly by many customers.

Prompt Service Response

Also important is the system of service—how promptly the appropriate response can be given in the event of a failure.
We at Cosmo Instruments have eight sales offices and four service centers in Japan.
We address this issue with a complete system. Leak testers require service before and after purchase, and we have assigned staff dedicated to each.

Problems Accompanying the Principle and Method of Identifying Acceptable Products by Zero Differential Pressure

Most manufacturers of leak testers using the differential pressure method have one difficult problem in common.
It arises from the principle and method that a product is judged as Pass if the differential pressure is below a certain fixed value, close to zero.
In other words, if the DPS output is stopped, if the valve is not functioning, or if conductions or leaks are happening inside the valve or the DPS, differential pressure could fail to occur even if there is a leak, or the pressure could fail to be detected even if it occurs. This is the problem.
Until the sensitivity is checked using the leak MASTER, the failure would not be noticed, passing even defective products.
It seems to be the case that products by many manufacturers of leak testers are not taking adequate measures to counter this issue.

At Cosmo, we have implemented the following measures to prevent this danger.

• At the end of every test, air is blown, and the DPS measures the difference in pressure occurring at that time to check the output of the DPS.
• We use poppet valves for the air valves, since they are resistant to dust and similar foreign objects. We also have attained a high durability of 10,000,000 times due to the automatic supply of grease for the lubrication wiper, built in to the bearings.
• Poppet valves, because of their structure, can minimize failure of valves due to oil shortages of dust and decrease in sensitivity due to internal leaks. They can be used without worry for a long time, even without maintenance work.
• Our DPS are equipped with automatic leak calibrators and Leak Masters, making it possible to run automatic sensor check programs regularly.
• Valve movements are checked during each step of the leak test cycle by monitoring the test pressure.

Taking all possible measures to prevent danger of this issue can be said to be a basic necessity for reliable leak testers.

The Challenge Continues

For Ever Improving Performance

Cosmo Instruments has, until now, encountered many problems and solved them, building up a record.However, there are still several points which require improvement. We will continue to work with all our power to solve these remaining problems.

Overcoming the Effects of Temperature

A prominent issue with leak tests is the effect of the temperatures of WORK and the environment.
We are working on developing methods appropriate for different requirements, starting with the temperature compensation unit for methods correcting the effects of temperature, because of the characteristic of correlation with the surface temperature of WORK.

Recommendation of Elliptical Rings

Further, as a measure regarding temperature, we have developed a method to minimize temperature change by changing the seal gasket.
The elliptical ring that we sell (in kits) are effective as a measure regarding temperature and are low in cost, with the advantage that O-rings of any size can be made in-house.
We would like popularize elliptical rings and strive for even more of an improvement in the performance of leak tests.

Overcoming the Effects of Deformation

Deformation is another impediment to leak tests, along with temperature. Most seal tooling—designed to stop leaks but without the mechanism to keep the sealing surface fixed—are usually not suitable for leak tests.

Effective methods for WORK which can change in shape exist, such as the Intelligent 2 Pneumatic Circuit—with an isobaric process—and the Multi-Comparison Method (patented)—in response to requests for higher precision and shorter testing time.

Development of Gel Gasket in Pursuit of Sealing Technology

We at Cosmo Instruments have developed sealing material which is extremely low in hardness and is superior in elasticity and durability.
It can be put to use in sealing uneven or cast surfaces, making it possible to perform leak tests on WORK of shapes which had conventionally been difficult.

This is also a fruition of customers’ requests which prompted the further advancement of Cosmo Instruments’ leak test technology.
By providing our customers with precise methods, we can attain higher quality leak tests.
We will continue working with our customers to solve problems, aiming to manufacture trustworthy products.