Seal fittings

Compression seal fittings are high performers

Techni Measure have introduced the Conax Technologies range of high quality compression seal fittings and temperature sensor assemblies into their range of products.

Compression seal fittings allow electrical signals from sensors and other electrical equipment to pass from the enclosed operational area to the outside world. They restrain the elements from moving as a result of pressure differentials, prohibit the leakage of gas/liquid media along the elements, and can electrically isolate the elements from the mounting device. Many different seals are available, and the Conax soft seal technology, allows for high pressure and high temperature applications.

Typical applications include pressure vessels, autoclaves, furnaces, holding tanks and pipelines. Typical systems include the PL series that are for multiple power leads and come supplied with 8 to 20 AWG Kapton insulated wire preinstalled. The TG series are supplied with or without wires and are for low voltage applications such as strain gauges and thermocouples. Split seals are also available.

Single element seals consist of a body, cap, sealant and follower, whereas multiple element seals also include a seat, follower and an anti-rotation pin to prevent wires/conductors from twisting and shearing. The element to be sealed passes through the holes in the sealing assembly components and the cap is then torqued to the recommended value, thus translating an axial force on the follower. This force compresses the sealant contained within the body housing so that the sealant conforms to the element, creating a seal. The elastic nature of the sealant allows it to flow into any voids between the seal and the element.

Aerospace application
An interesting application involved several heater power feed-throughs for an autoclave in the Aerospace industry.

While it was intended to be an exact physical replacement of an existing product, Conax developed a "plug and play" solution offering several key advantages updates to the design, improved performance, longer life and ease of use. These units can be rebuilt in the field and spare parts are kept in stock at the customer site. Downtime is now limited to 3-4 hours to replace a few simple components, compared to 3-4 months for complete rebuilds of the previous design.

Performance and longevity are improved so that the heating elements can function at peak performance at all times rather than a continuous degradation in performance until failure as with the old design. This application typifies what is possible from the Conax range and by utilising their application experience.