Seat Qualities Brochure

SEAT LINERS FEATURES They are specially designed by VAMEIN DE ESPAÑA, S.A. to allow a perfect fit with the valve's body and making it completely watertight. Their O-RINGS allows a perfect seal with the flanges without requiring any additional joints. For the valve life and perfect working it is imperative that the right seat material is chosen for the line conditions, i.e., temperature and chemical composition of fluid. VAMEIN DE ESPAÑA, S.A. Technical Department is prepared to help you choose the right kind of seat. Do not hesitate to ask about the particular conditions of the fluid to be used. N.B: Some advice is given on the selection of discs and seats in CHAPTER IV. DETAILED WAYS ON FITTING THE SEAT TO THE BODY AND SHAFT PITCH DETAILS THROUGH THE SEAT. Shaft It is perfectly watertight due to "O-RINGS" moulded seals to seal the shaft. DN 600  DN 650 - 1200DN 50 - 300   DN 350 - 500 MATERIALS: Here are the basic ways in which the most common seats behave in technical terms at an informative level. The following values are used for the most common seat standard formulation, although depending on the fluid used, VAMEIN DE ESPAÑA, S.A. has special formulations to make the same basic seat resist more heat and expansion volume than those specified below. For further information, contact our Technical Department. MAIN FEATURES OF THE MOST COMMON SEATS. EPDM: CHEMICAL DENOMINATION: ETHYLENE-PROPYLENE RUBBER. Very good resistance to outdoor weather, the ozone and heat. Good resistance against water vapour, acid, bases, animal and vegetable grease and oxygen solvents. (Ketone, etc) Poor resistance against bare flame, aliphatic and aromatic hydrocarbons. Not usable when in contact with petrol, oil, grease and carbohydrate solvents. NITRILE.- (BUNA-N): CHEMICAL DENOMINATION: BUTADIENE-ACRILONITRILE RUBBER. Very good resistance to aliphatic hydrocarbons and vegetable and animal fats. Good resistance against diluted acids. Poor resistance against oxygen and halogen solvents. Not usable when in contact with aromatic hydrocarbons (benzene, toluene, xylene, etc.); or chlorated hydrocarbons (chloroform, trichloroethylene, etc). HYPALON: CHEMICAL DENOMINATION: CHLOROSULPHONATED POLYETHYLENE RUBBER. Very good resistance to outdoor weather, the ozone, diluted acids, alkali and heat. Good resistance to water concentrated acids, animal and vegetable fat and oil. Poor resistance to aliphatic and aromatic hydrocarbons. Not usable when in contact with halogen or oxygen solvents. VITON®: CHEMICAL DENOMINATION: FLUORCARBONATED RUBBER. Very good resistance to heat, outdoor weather, the ozone, water, diluted and concentrated acids, aliphatic and aromatic hydrocarbons, vegetable and animal fats. Good resistance to halogen solvents. Not usable when in contact with oxygen solvents SILICONE: CHEMICAL DENOMINATION: POLYXILOXANE RUBBER. Very good resistance to heat, outdoor weather and the ozone. Poor resistance to diluted and concentrated acids, alkali, oxygen solvents and vegetable and animal fats. Not usable when in contact with aliphatic and aromatic hydrocarbons. NEOPRENE: CHEMICAL DENOMINATION: POLYCHLOROPRENE RUBBER. Good resistance to heat, outdoor weather, the ozone, concentrated and diluted acids, vegetable and animal fats, and aliphatic hydrocarbons. Poor resistance to aromatic hydrocarbons, halogen and oxygen solvents. N.B.: AUTOEXTINGUISHABLE seats can be manufactured with the above types of rubber. TABLE OF TEMPERATURES. MATERIAL VAMEIN CODE COMERCIAL CODE ° C MINIMUN TEMPERATURE ° C MAXIMUN TEMPERATURE EPDM E EPDM -15 100 (110) EPDM HIGH TEMPERATURE EC EPDM HT -15 120 (130) NITRILE N NBR -15 100 (115) HYPALON H CSM -15 105 (115) VITÓN® V FKM -20 180 (200) SILICONE S VMQ -40 180 (200) NEOPRENE Ne Cr -25 100 (115) N.B.: There are two possible maximum temperatures, depending if the temperature applied is constant or intermittent. Those shown in brackets refer to the intermittent temperature. It is to be taken into account that the more the working temperature approaches the limit temperature of the liner, the more premature ageing will take place and its original qualities reduced more quickly. Temperatures just as an information.