Reduce your Total Cost of Ownership with high-quality valves
Throughout their “youth”, all gate valves do well. But with time, wear and tear takes its toll, and the differences between good and bad quality become apparent. A quality valve will continue performing effortlessly, whilst the cheap valve will require more and more maintenance at a very high cost.
State-of-the-art rubber technology
AVK wedges are fully vulcanised with AVK’s own rubber. AVK GUMMI A/S develops and manufactures rubber compounds using highly advanced technologies. The wedge core is immersed in two different baths to provide ultimate bonding between core and rubber. Even if a sharp object penetrates the rubber during closing of the gate valve, the bonding is so strong that there is no risk of creeping corrosion.
Rubber with excellent ability to regain original shape
AVK’s rubber compounds have an unrivalled compression set, meaning its ability to regain its original shape after having been compressed. Impurities will be absorbed in the large layer of rubber in the sealing area when the gate valve is in closed position ensuring a 100% tight sealing. They are flushed away when the valve is reopened and the rubber will regain its shape.
AVK gate valves do not contaminate the drinking water
The EPDM rubber recipes are composed with focus on minimising the formation of biofilm. The rubber will therefore not provide breeding ground for bacteria. The drinking water approved EPDM compounds are resistant to ozone and water treatment chemicals and will remain flexible preventing cracks and damages. The compounds are of course taste, smell and color neutral.
Find more details on AVK's unique rubber
Fixed wedge nut and wedge shoes ensure smooth operation of the gate valve
AVK’s wedge nut design with a fixed, integral wedge nut outperforms the traditional loose wedge nut design as it prevents vibration and thus also wear of the rubber surface and corrosion. It is made of brass certified for use in contact with drinking water according to the stringent EU standards.
The fixed wedge nut and the guide rails fitted with vulcanised wedge shoes secure a smooth operation of the gate valve and low operating torques. The wedge shoes protect the rubber against the wear which otherwise would arise from friction during operation. The wedge shoe is made of drinking water approved polyamide and is fully vulcanised to the wedge core for maximum corrosion protection.
Wedge stop and rolled threads ensure durability
The wedge stop provides a firm stop against the wedge nut when opening the gate valve. This prevents the wedge from compressing the stem seals and from damaging the coating inside the bonnet. Therefore, the wedge stop gives prolonged durability of the gate valve. The stem threads are rolled in a cold pressing process which maintains the steel structure and therefore increases the strength of the stem. This method also ensures a smooth thread surface that gives low operating torques of the gate valves.
Triple safety stem sealing
An NBR wiper ring protects against impurities from the outside. Tightness and low friction are provided by four NBR O-rings in a polyamide bearing or in a replaceable stem seal nut of dezincification resistant brass. A rubber manchette is the main seal to the flow, made of EPDM for water and NBR for gas and wastewater applications. The full circle thrust collar of high strength dezincification resistant brass provides fixation of the stem. It reduces the friction and thus also the torques.
Corrosion-proof gate valve assembly
The bonnet gasket fits into a recess between the valve body and the bonnet to protect it from being blown out at pressure surges. The stainless steel bonnet bolts are encircled by the bonnet gasket to ensure that no threads are exposed to the surroundings, and finally sealed with hot melt to prevent corrosion.
Three strong coatings for gate valves
The standard corrosion protection is an internal and external epoxy coating in compliance with DIN 3476 part 1, EN 14901 and GSK guidelines. Furthermore, we offer gate valves with a highly wear-resistant internal enamel lining well-suited for abrasive media as it forms a chemical bond with the casting preventing creeping corrosion. Finally, AVK also offers gate valves with an external PUR coating according to EN 10290 type 2, class B, developed for use in steel gas pipelines with cathodic protection, but also a good choice for installation in aggressive soils.
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