William Johnston & Company Limited offer semi-metallic gaskets which are designed to feature soft, pliable sealing materials with lower overall load requirements when compared to fully metallic gaskets.
There are different styles of semi-metallic gasket to choose from:
|Spiral Wound Gaskets are very suitable for applications featuring heavy operating conditions & where high integrity is required. They can be used for sealing flange joints, manhole and handhold covers, tube covers, boilers, heat exchangers, pressure vessels, pumps, compressors and valves etc.
High integrity sealing for various applications
Available in standard and non-standard configurations
Various metals and fillers available
|Kammprofile Gaskets are the preferred gasket solution when improved sealing and safety performance is required. Metal gaskets with serrated faces have proven to be very effective for sealing flange connections, particularly for applications where high temperatures, pressures and cycling conditions are encountered.
Suitable for a range of chemicals.
Suitable for use in high pressure and high temperature applications.
Can be refurbished and reused.
Can be manufactured to suit standard flange applications and vessels.
Can be manufactured for use with narrow flanges.
Low sealing stress required for installation.
|Corrugated Metal Gaskets comprise solely of metal and do not contain any non-metallic filler in their construction. The temperature limitation of the gasket is only affected by the metal selected.
Suitable for uneven or distorted sealing surfaces.
Offer a more elastic material with better sealing performance.
Used on low-pressure applications usually in large diameter flue gas ducts at high temperatures.
|Metal Jacketed Gaskets are particularly suitable for sealing the flat surfaces of heat exchangers, pipe flanges, boilers and process equipment. The metal outer jacket protects the inner soft resilient filler from corrosive substances, pressure and temperature. They are manufactured from a wide range of soft metals with or without filler.
They are all custom made so there are few limitations regarding size and shape.
The jacket provides mechanical strength to contain the filler and improves chemical resistance.
Unique construction provides stability and ensures trouble-free handling and installation.
Can be manufactured to suit narrow flanges.
|Metallic Insert Gaskets offer special protection against blowout when sealing critical or dangerous substances. The austenitic stainless steel inner eyelet offers excellent protection for the soft gasket material against erosion and corrosion, while it also prevents contamination towards the medium within the pipeline.
Blow out protection.
Protection against chemical attack.
Improved sealability due to the local higher stress under eyelet.
Although we do not consider maximum temperature or pressure in isolation the charts below give an indication as to the maximum possible temperature assuming no pressure and maximum possible pressure assuming no temperature.