Doyma: Curaflex Gasket Inserts
Doyma develops and produces gasket inserts for sealing penetrations through walls, ceilings and floors for the widest variety of situations. The spectrum of applications for gasket inserts encompasses structural and civil engineering, especially water lines, heating and district heating. Other applications include, for example, service ducts in swimming pools, bund and tank installations, gas pipes and civil defence shelters. Further uses occur in manholes, sewage works and in constructions with or without tanking membranes and thick coating renders. The Curaflex® gasket inserts fulfil the following construction engineering requirements
- Sealing against pressing and non-pressing water.
- Gasket inserts for sleeves as well as core bores.
- Split versions for retrofit installations.
- Angular deviations up to 8°
- Fire protection: With intumescent systems tested and approved to DIN 4102 of the Building Regulations, fire compartments can be penetrated with confidence.
- Explosion protection.
- Doyma gasket inserts are also gas tight in their function.
Function principles
The assembly comprises rubber gaskets between profiled steel rings, which fits over the service pipe/cable inside the sleeve or core bore. Tightening the nuts compresses the gaskets between the steel rings and thereby securely closes off the annular void between the building service and the sleeve or core bore. The profiling of the steel rings (DPS - Double Profile System) causes the intelligent distribution of the compression pressure: gently in the direction of the service, strongly in the direction of the sleeve/core bore.
Materials used
The standard gasket insert comprises minimum 5 mm thick, asymmetrically profiled steel rings with DPS*. The steel rings are electro galvanised, yellow chromated and sealed as standard. To these are added - according to the sealing requirement for pressing or non-pressing water - one or two 27 mm thick elastomeric rings which, as standard, are in the low compression set special EPDM compound 'Doyma Grip'. Gasket inserts with two elastomeric rings have an additional 3 mm thick orange-coloured EPDM middle ring. This middle ring causes homogenous and uniform distribution of the compression pressure on the service pipe or cable and sleeve/core bore.
Steel grades
- S235 JRG2 (1.0038)
- Stainless steel grade 304
- Stainless steel grade 316
- Other materials on request
* DPS up to 350 NB
Surface treatment
- Electro galvanised mild steel (DIN 50961), yellow chromated and sealed with a plastic coating.
(Chromating approximately doubles the corrosion resistance of electro galvanised steel; sealing with the plastic coating doubles the resistance yet again - a four-fold improvement over simple electro galvanised steel). - Stainless steel grades 304 and 316 supplied in pickled condition.
- Other materials and surface treatments available on request.
Gasket polymers: Polymer types
EPDM (Ethylene Propylene Di-Monomer)
- Specially developed 'Doyma Grip'. Doyma Grip is a special, slip resistant, resilient elastomeric compound developed by Doyma. This compound resists friction-reducing substances, for example softening agents, which can cause the gasket insert to slip.
Additional properties:
- Excellent chemical resistance, resistant to almost all acids and alkalis as well as brine.
- Suitable for potable water (KTW-recommendation on request).
- High thermal and mechanical properties.
- Not suitable for oils, fats, fuels and solvents.
- Temperature range: from -40° C to +140° C.
NBR (Nitrile Butadiene Rubber - Perbunan*)
- Resistant to oils, fats and all commercially available fuels.
- Not suitable for solvents, chemicals, aviation fuels and fuels with a high proportion of methanol.
- NBR is an outstanding seal for natural and town gases.
- Temperature range: from -40° C to +80° C.
FPM (Fluor Rubber - Viton*)
- Chemical resistance, also to solvents, fuels, natural gas, oils, fats and aviation fuels - Jet A1 (old designation: JP1 & ATK) and Jet B (old designation: JP4 & ATG).
- Temperature range: from -30° C to +200° C.
Silicon (Silicon Rubber)
- Good temperature resistance to 250° C.
- Good ozone resistance.
- Limited chemical resistance - not suitable for oils, fuels and solvents.
- Temperature range: from -90° C to 250° C
* Registered trade name
NB! Gasket inserts are not designed as service supports and are not designed for load bearing. If settlement of pipelines is expected, centring rings or spacers should be fitted in the sleeve or core bore during installation.