JPS57154564A - Double seal valve - Google Patents

Abstract

PURPOSE:To simplify cleaning of valve boxes, two-way cocks and spaces between each valve body, by arranging at the connection of the valve body and two-way cocks, two valve bodies to be opened and closed individually and another valve body positioned between the above mentioned two valves. CONSTITUTION:When fluid flows, compressed air is charged through a second air vent 27 to raise an outer piston 16, a rod 20, a main valve stem 7, an outer valve body 8 and a leakage discharge pipe 11. Consequently, the outer valve 8, an intermediate valve body 14 and an inner valve body 13 are brought in their open positions while making contact with each other. When only the side of the valve box 3 is to be cleaned, compressed air is supplied simultaneously through a first air vent 26 and a fourth air vent 29 to open only the inner valve 13 a little. Then, the liquid is discharged from the liquid leakage discharge pipe 11 little by little through the space between the upper face of the intermediate valve body 14 and the bottom face of the inner valve body 13, a gap 31, and a small hole 14. When only the two-way valve 30 is to be cleaned, compressed air is supplied through a second air vent 27 and a third air vent 28 to open the outer valve body 8 a little to dischage liquid little by little from the liquid leakage discharge pipe 11 through the upper face of the outer valve body 8 and that of the intermediate valve body 14.