TY - JOUR
AU1 - Kottmann, A.
AU2 - Lutz, J.
AB - UDC 621o646.5.001o5 A. Kottmann and J. Lutz Studies of the internal coatings in water valves were conducted during 1972-1990 by the technical firms in Stuttgart. During the Second World War gate valves with water bags and metallic seals wore used in the water supply lines~ The internal surfaces of the valves were coated with asphalt for corrosion protection. Lime and rust deposits soon formed on these coatings~ Movement of the wedge gate caused these deposits to peel off and fall into the water bags, thereby disrupting the sealing of the valve. Improvements in gate valve design was started by some manufacturers only after 1950. The metallic seals were replaced with elastic seals and the wedges were coated with rubber. These valves had major shortcomings as the sealing surfaces were merely painted. The wedge with rubber coating tended to compress the deposits and reliable sealing could not be achieved. The sealing rubber used by some manufacturers disintegrated and escaped into the water supply within a few years. The hemp glands also caused many problems. Therefore, it is not surprising that gate valves were considered at that time to be the weak link in pipelines. During 1960-1970 many manufacturers continued to 
TI - Fifteen years of research on water valves
JF - Chemical and Petroleum Engineering
DO - 10.1007/BF01235651
DA - 2005-02-12
UR - https://www.deepdyve.com/lp/springer-journals/fifteen-years-of-research-on-water-valves-blRz0YD87Y
SP - 327
EP - 329
VL - 27
IS - 6
DP - DeepDyve
ER -