For fire trucks, the important thing is that the centrifugal pump does not require complicated transmission of the engine, and the centrifugal pump has small dimensions and light weight. Centrifugal pumps also have some disadvantages: they cannot pump liquid by themselves, and can only work if the suction line and pump are pre-filled with water.
Filling the suction line and pump chamber with water from a water tank can compensate for this shortcoming. In addition, an auxiliary pump is installed on the fire truck to fill the suction pipe and pump body with water. For this purpose, air jet, rotary and other types of pumps are used. The working time of the auxiliary pump is short, only at the moment when the centrifugal pump is put into operation. The installation of such a pump complicates the structure of the water pump unit because an auxiliary drive must be installed.
Axial forces are generated when the pump is running. This increases the load on the bearings, reduces their lifespan, and can cause the pump impellers to drift toward the pump cover or even touch each other. Typically, pumps are designed to reduce this axial force using pressure relief holes in the impeller cover, but this reduces pump efficiency.
In many cases radial thrust bearings are used on the pump shaft. Under certain conditions, cavitation may occur in the centrifugal pump. It is important to take measures to prevent this phenomenon. The most important measures are as follows, to limit the depth of water absorption; the sealing degree of the suction pipeline should be high; the shape of the impeller and the pump body should be reasonable, and the materials with cavitation resistance should be selected.
The price of each fire pump is high or low. Generally, it depends on the pump type and the number of impellers and how much one is calculated. For example, a multi-stage pump with more impellers is more expensive than a single-stage pump. For example, the price of XBD-DL fire pump is different from that of general DL type multi-stage pump. The price of DL type multi-stage pump is about 1500-2200, while the market price of XBD-DL fire pump is about 4000. The main reason is the resistance of fire pump. The pressure performance is good, and the injection is higher and farther, so the price is relatively more expensive.
Vertical fire pumps are relatively cheaper than horizontal fire pumps, and different manufacturers also directly affect the price difference of fire pumps.To introduce the price of fire pumps on the market, we must first talk about the purpose of the pump. Due to the use of the pump and the impeller, single suction and double suction, the price varies. First of all, understand the technical performance of the fire pump and the centrifugal pump installed on the fire truck. Because this pump has the following many advantages: uniformity, no fluctuation when supplying extinguishing agent; good "self-control" ability, that is, the pressure in the water supply system does not increase sharply when the fire gun is closed, the fire hose is blocked or bent, thus ensuring The reliable operation of the water pump device is ensured; the operation is simple, and the maintenance during operation on the fire field is not complicated.
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