To prevent a hot water delivery apparatus from being lifted together in drawing upward a drain part of a water tank while sealing between the drain part of the water tank mounted on the hot water delivery device and a drain acceptor of the hot water delivery device with packing.
A tongue piece part 15b having a sealing surface 15c of the packing 15 is released outward while the contact between the sealing surface 15c and an outer peripheral sealing surface 23 is kept by the drain part 21 inserted into the drain receiver 14, and when the drain part 21 is opened, an annular space 40 formed on the back of the released tongue piece part 15b and the inside of the water tank 20 communicate with each other, and the tongue piece part 15b is subjected to water pressure from the back so that the sealing surface 15c is pressed to the outer peripheral sealing surface 23. As compared with the sealing force required for sealing between the sealing surface 15c and the outer peripheral sealing surface 23, the elastic sealing force derived only from the elasticity of the packing 15 is smaller, but auxiliary sealing force produced by pressing of the sealing surface 15c is added the moment the tongue piece part 15b is subjected to water pressure, thereby sealing the space up to the outer peripheral sealing surface 23.
SAKAGUCHI RYOICHI
Torii Kazuhisa
Takayoshi Tagawa
Tounaga Mitsuhiro