Compressor Seals for CO2

Product Description

Carbon dioxide (CO2) does not contribute to global warming as much as conventional refrigerants such as CFCs (chlorofluorocarbon) and FCs (fluorocarbon). It is hence gaining increasing usage as an environmentally-friendly refrigerant in modern heat pumps for air conditioning systems, refrigerators and other cooling applications despite its lower efficiency level.

However, due to its high vapor pressure, compressors for heat pumps using CO2 as the refrigerant have to be designed for up to 10 times higher pressures than classical compressors.

Compressors are often placed outdoors and are exposed to adverse environmental conditions such as humidity, pressure, vibration and various chemical influences. At the same time, compressors utilizing CO2 as a refrigerant operate at pressures and temperatures (up to 180ºC) much higher than conventional compressors.

With harsh environmental conditions acting both within and outside of the compressor, it is necessary that the housing is durably and hermetically sealed to ensure the continued safe and reliable performance of the compressor. This is why glass-to-metal sealing (GTMS) technology is the most promising solution for CO2 compressor seals, since GTMS consist only of very resistive materials.

Glass-to-metal compressor seals are electrical feedthroughs consisting of a metal base and glass elements which hermetically seal in metal leads to the base. Compressor sealsprovide an electrical conduction terminal and at the same time function as a hermetic “cover” for the compressor, protecting the internal components of the compressor from undesirable ambient influences, as well as preventing any leakage of the refrigerants from within. The strong hermetic seal is possible due to the compressive stress that the eyelet exerts upon the glass seal.


Glass-to-metal sealing (GTMS) technology is ideal for such demanding applications because of its extremely resistant and durable materials. The special glass composition used has excellent electrical insulation characteristics. Furthermore, the compressive sealing method technique also provides high material strength and outstanding pressure resistance

With more than 50 years of experience with GTMS technology, we can offer customers optimal material combinations and manufacturing processes for a variety of demanding applications on a consistently high quality level. In addition to a wide range of standard housings, we can also customize the products in close co-operation with our customers.


Compressors for heat pumps using CO2 as a refrigerant represent a special field of application. GTMS compressor seals can be used in all modern CO2 coolant compressors used for heat pumps which are found in refrigerators, air conditioning systems and water heaters.

Technical Details


Compressor seals utilize glass-to-metal sealing technology to achieve a high quality of hermeticity. For more information about our glass-to-metal technology, please click on this page. Alternatively, you can find out about our GTMS products from the Hermetic packaging and sealing technology handbook.

Features / Specifications

We provide a wide range of standard seals and also work closely with customers to develop customized products.
Base Steel
Lead FE/CR
Glass Soda Barium glass
Finish Nickel plating

Please contact us for more details.

Forms of Supply and Product Packaging

Standard forms of supply are available. Please contact our sales department if you have special requests concerning supply and packaging.


All of our glass-to-metal sealing products are manufactured in our ISO 9001/14001 certified plant, the quality assurance standard of ISO. For more information, please click here.
Trade Fairs & Events
Trade fair Gastech, Barcelona, Spain, 17.09 - 20.09.2018
Trade fair electronica, Munich, Germany, 13.11 - 16.11.2018
Christoph-Dorner-Strasse 29
84028 Landshut
E-Mail to SCHOTT+49 (0)871/826-0
SCHOTT uses Cookies on this Website to enhance the user experience and provide the best possible Service. By continuing to browse the Website, you consent to our use of Cookies.