TANDEM TYPE MECHANICAL SEAL DEVICE OF PUMP

摘要

PURPOSE:To simplify a structure and exhibit always sealing performance stably by providing such constitution that seal liquid of a low pressure step mechanical seal is led-in and supplied from a pump suction side, in the device in the title to be used after being assembled in the cooling water circulating line of a water cooled device or the like. CONSTITUTION:Liquid leading pipes 12, 13 are arranged between the suction port 3a end surfaces of a pump casing while extending those pipes from upper/lower end parts of a low pressure side liquid chamber 9 containing a low pressure step mechanical seal 7L. When operation is started, seal liquid therein is filled-up into the low pressure side liquid chamber 9 through another supply port. When normal operation is started here, suction side pressure of a pump 3 is applied into the low pressure side liquid chamber 9, so that intermediate pressure between outside air pressure and enclosed fluid pressure on the ejection side applied into a high pressure step mechanical seal 7H, is applied into the sealing liquid of the low pressure step mechanical seal 7L. Also, when the sealing liquid quantity in the low pressure side liquid chamber 9 is reduced by leakage of the low pressure step mechanical seal 7L, the seal liquid is promptly supplied from a pump suction side through the leading pipes 12, 13, so that respective mechanical seals 7H, 7L of the high and low pressure steps can be used always in a stabilized condition.