When to Replace Profile Rings

When you think about it, the rubber in sealing rings is an amazing material. It is a recent discovery, only introduced in 1736. It was not until 1700 that Joseph Priestley developed rubber in its first commercial use as a pencil eraser. The usefulness of rubber lies in its elasticity, defined as the ability of rubber to deform reversibly under stress. When placed between two highly inelastic pieces of metal, it deforms to form a seal that is highly impervious to liquid or gas passage, even under extreme temperatures and pressures. Thermoplastics are a modern form of elastic sealing material which forms the basis of high-performance profile rings in compressors.


What Makes Profile Rings Fail?

Much like our skin, which is also highly elastic when we are young, thermoplastic material loses its inelasticity with age. This process is sped up in the presence of extreme temperatures or caustic materials. In other words, aged profile rings lose the ability to return to its original form. This reduces its ability to form an effective seal.


Symptoms of a Failing Seal

In many systems, the first symptoms of a failing seal are a visible leak at the seal joint. In a compressor system, the symptoms are less obvious. One of the key symptoms is a loss of pressure. Although this can be attributed to the age or degradation in several parts of the system, the most common point of failure is the system. For this reason, monitoring pressure is an excellent way to determine when profile rings need to be replaced.

Failing rings are not like a flat tire. They do not fail all at once. The effect of their degradation is more like a slow leak. For this reason, the technician who monitors pressure as a means to determine the useful lifetime should have a boundary failure level for pressure, one well in advance of the pressure requirements of the system.


Replace Them All

Thermoplastic failure in a particular system is highly predictable. When one seal begins to fail, the others will soon follow. For this reason, it is a good idea to replace seals at the first sign of degradation, or alternately, on a fixed time schedule.



  • Metallic Plates

    KB Delta manufactures and stocks a complete range of metallic compressor valve plates and rings for the natural gas, refrigeration and P.E.T. industries.

  • Thermoplastic Plates

    Our specialized precision tooling and proprietary lapping process gives our customers the highest quality thermoplastic plates and rings in the industry.

  • Springs

    We manufacture our own springs and stock over 2 million springs for a variety of OEM spring styles, forms and materials.

  • Peripheral Valve Internals

    KB Delta offers one of the most complete lines of valve internals in the industry. All of our parts are manufactured to OEM Standards in performance and efficiency.

  • Complete Valve Repair Kits

    KB Delta offers a full line of valve repair kits for all the major reciprocating compressor manufacturers.

  • P.E.T. Compressor Parts

    KB Delta specializes in manufacturing compressor valve parts for high pressure air compressors used in the P.E.T. plastic bottle manufacturing industry.

Industries we serve

Natural Gas Industry

The processing and refining of Natural Gas into a marketable products, by separating gas into pipeline-quality natural gas and a stream of mixed natural gas liquids and the transportation of natural gas to through a series of reciprocating compressor stations and pipes, and from there to end users.

Blow Molding Industry

This industry manufactures blow molding machinery. Injection stretch blow molding process has two main different methods, a single-stage and two-stage process; these are the methods by which hollow plastic parts are formed.

Medical Technology Industry

The medical technology industry is an important part of the healthcare sector. It includes most medical devices which aid the prevention, diagnosis and treatment of diseases and illnesses. Established centers of this industry include the United States and Western Europe.