Fire fighting pump and its operating methods

Abstract

A fire fighting pump and operation thereof and a fire fighting system and a fire engine, wherein the pump includes a housing, a motor mounted inside the housing and two or more stages of series-connected impeller assemblies. A water inlet is provided on the housing between the motor and the impeller assemblies. The impeller assemblies are mounted on the impeller shaft coaxially and in series with each other. The impeller shaft is fixed on the motor shaft or is coaxial with the latter. The impeller assembly includes a thruster, an impeller, an end cover and a retaining ring on the periphery of the thruster and the impeller, and those four elements are installed in turn. Several first blades are provided in the thruster and several second blades which correspond with the first blades in amount and location are provided in the impeller.

1 . A fire pump comprising a pump housing, a motor fitted inside the pump housing, and series-mounted impeller assemblies of 2-stage or over 2-stage that are fitted inside the cylindrical cavity of the pump housing, a water inlet being provided on the pump housing between motor and impeller assembly, impeller assemblies being coaxially series-mounted on the impeller shaft, impeller shaft being fixed on the motor shaft or shares motor shaft, characterized in that the impeller assembly includes end cover, thruster, impeller and retaining rings, the first vent is provided in the center of the end cover, the thruster includes the central shaft, 3 or more than 3 first blades, the first hub and the second hub, the first blades are placed between the first hub and the second hub. 3 or more than 3 first division grooves are formed among the first hub, the first blades and the second hub, inside the central shaft is the second vent that matches the impeller shaft, the thruster is fixed on the impeller shaft via the second vent, the impeller includes the second blades whose number is the same as those of the first blades, the positions of the third hub, the fourth hub and the second blades correspond with the position of the first blades, the second blades are placed between the third hub and the fourth hub, the second division grooves are formed among the third hub, the second blades and the fourth hub, whose groove number is the same as those of the first division grooves, the third vent that matches the central shaft of the thruster is provided in the center of the impeller, the third hub of the impeller is supported on thruster's second hub while thruster's central shaft is coupled inside impeller's third vent, retaining rings are fitted on the outer peripheries of the impeller and thruster, end cover is mounted on the impeller, a sealed water flow passage is formed among the end cover's vent, the first division groove of the thruster, the second division groove of the impellers and the retaining rings, the end cover and thruster are installed together between the two neighboring impeller assemblies, and a sealed water flow passage is formed between the impeller assemblies. 
   
   
       2 . The fire pump as claimed in  claim 1 , wherein the first positioning ring is equipped in the direction of the first hub reverse to the outer periphery along the small end of thruster's first hub. The first positioning ring is fitted inside the first vent of the end cover and matches the first vent. 
   
   
       3 . The fire pump as claimed in  claim 2 , wherein that the second positioning ring is fitted in the direction of small end of the fourth hub facing the big end of the outer periphery along the fourth hub of the impellers. The first step is fitted on the second positioning ring. The inner periphery of the retaining ring matches the outer periphery of the first step. 
   
   
       4 . The fire pump as claimed in  claim 3 , wherein the third step and the fourth step are provided on the end cover, the outer periphery of the third step matches the inner periphery of the retaining ring, and the outer periphery of the fourth step matches the inner periphery of the second positioning ring. 
   
   
       5 . The fire pump as claimed in  claim 4 , wherein the maximum outer diameters of the end cover, retaining ring and the second positioning ring are equal. 
   
   
       6 . The fire pump as claimed in  claim 5 , wherein the number of stages of the described impeller assembly is 30˜74 while the number of the first blades of the described thruster is 3˜12. 
   
   
       7 . The fire pump as claimed in  claim 6 , wherein the first hub and the second hub of the thruster are of open and diplex umbrella type, the first hub and the second hub are in parallel; the third hub and the fourth hub of the impeller are of open and diplex umbrella type, and the third hub and the fourth hub are in parallel. A rubber ring is fitted between the third vent of the impeller and the central shaft of the thruster. 
   
   
       8 . The fire pump as claimed in  claim 7 , wherein the maximum outer diameter of the first hub is greater than the maximum outer diameter of the second hub, the maximum outer diameter of the fourth hub is greater than the maximum outer diameter of the third hub, while the maximum outer diameters of the second hub and the third hub are basically the same, and helical direction of the first blade is reverse to that of the second blade. 
   
   
       9 . The fire pump as claimed in  claim 8 , wherein the described pump housing is of cylindrical shape and the described end cover, thruster, impeller and retaining ring are made of stainless steel material. 
   
   
       10 . An operating method of a fire pump, wherein the fire pump includes a pump housing, a motor installed inside the pump housing, and 2-stage or over 2-stage series-mounted impeller assemblies installed inside the cylindrical cavity of the pump housing, a water inlet is provided on the pump housing between the motor and the impeller assembly and impeller assembly is coaxially series-mounted on the impeller shaft, impeller shaft is fixed on the motor shaft or shares motor shaft, characterized in that the described impeller assembly includes the thruster, impeller and end cover, around the thruster and impeller are equipped with retaining rings, thruster is equipped with the first blades, impeller is equipped with the second blades whose number is the same as that of the first blades, but with corresponding positions, thruster is fixed on the impeller shaft while impeller is coupled on the impeller shaft, end cover passes through the impeller shaft, during pumping water, operating process includes that impeller shaft rotates together with the motor shaft, impeller shaft drives the thruster fixed on the impeller shaft to rotate, impellers, retaining rings and end cover of the impeller assemblies rotate irregularly under the action of the thruster.