Industry News

Vehicle fire pump refers to a non-powered fire pump installed on the Isuzu chassis of a fire truck. Vehicle fire pumps usually use the engine on the Isuzu fire truck to drive the fire pump, transfer energy to the medium water, and then reach the fire monitor or fire gun and other equipment through the pump outlet to extinguish the fire. Vehicle fire pumps are divided into high-pressure fire pumps, medium-high-pressure fire pumps, medium-pressure fire pumps, high-pressure fire pumps and high-pressure fire pumps according to their outlet pressure.

Let us take a look at the structures and principles of several vehicle fire pumps:

1. High-pressure centrifugal fire pump: When the pump is filled with liquid, as the impeller rotates, the liquid in the chamber is pushed out and flung from the center of the impeller to the surroundings under the action of centrifugal force. After being collected, it flows out from the pump outlet, completing the water pressure process. At the same time, as the water in the center part of the impeller is thrown out, a vacuum is formed at the entrance of the impeller. Then, under the action of atmospheric pressure, water enters the suction chamber of the pump body from the water suction pipe, thereby completing the water absorption process. The centrifugal pump works by continuously completing the process of pressing water and absorbing water under the continuous rotation of the impeller. However, because the centrifugal pump does not have the ability to exhaust and guide water, the necessary condition for the centrifugal pump to work is to fill the pump with water in advance. For vehicle fire pumps, a special water diversion device needs to be installed. When the water diversion device works, the air in the pump and water suction pipe is removed, forming a certain degree of vacuum, and water from the water source is introduced under the action of atmospheric pressure. When the pump works normally, its own operation can maintain the internal vacuum requirements.

2. There are three main forms of medium and high pressure fire pumps. Medium and high pressure fire pumps can be divided into two-stage centrifugal type and single-stage centrifugal type according to the number of impellers. The two-stage centrifugal type can be divided into two-stage series-parallel type and two-stage Tandem type.

A. In a double-stage series-parallel medium-high pressure fire pump (series-parallel fire pump), when the first-stage impeller and the second-stage impeller work in parallel, the outlet of the pump outputs high-pressure water flow, and when the first-stage impeller and the second-stage impeller work in series, medium pressure is output. water flow. The primary impeller outlet of a two-stage tandem medium-high pressure fire pump (tandem medium-high pressure pump) outputs high-pressure water flow, while the secondary impeller outlet outputs medium-pressure water flow. Single-stage centrifugal medium-high pressure fire pumps generally rely on changing the pump speed to output high-pressure water flow and medium-pressure water flow.

B. The centrifugal vortex fire pump is a typical structure of a high-pressure fire pump. This pump is composed of a single-stage centrifugal pump and a vortex pump connected in series. It has the functions of a single-stage centrifugal pump and can produce high-pressure water as needed. High-pressure water equipment and water injection equipment. The centrifugal vortex pump has the advantages of small size and compact structure, especially its generally configured high-pressure hose reel and high-pressure water gun system, which enables quick dispatch when extinguishing fires and meets the requirements for rapid response.

C. The impeller of the vortex pump is the boosting element of the centrifugal vortex pump. There are several grooves on both sides of its periphery, and each groove is equivalent to a blade. When the impeller rotates, the liquid in each groove is thrown out radially along the bottom edge of the groove by centrifugal force. After the pressure at the top increases, it moves toward the bottom of the groove along the periphery of the flow channel, forming a liquid in the pump. inner loop. At the water inlet of the vortex pump, due to the widening of the flow channel, the liquid is sucked in. After the impeller is rotated and pressurized, it is squeezed out at the water outlet due to the sudden contraction of the flow channel section. Because there are many grooves around the impeller, the vortex pump can be equivalent to the supercharging effect of several stages of centrifugal impellers. Generally speaking, the pressure increased by a vortex pump impeller can reach 3-4Mpa.