中低压消防泵主要有四种结构型式：中低压单级离心泵、中低压两级离心泵、中低压串并联离心泵和中低压串联离心泵。

There are mainly four structural types of medium and low pressure fire pumps: medium and low pressure single-stage centrifugal pump, medium and low pressure two-stage centrifugal pump, medium and low pressure series parallel centrifugal pump and medium and low pressure series centrifugal pump.

中低压单级离心泵：

Medium and low pressure single-stage centrifugal pump:

基本结构类似于低压单级离心泵，泵腔内装有叶轮。形成介质压力的基本原理是通过提高水泵转速来调节压力。中低压单级离心泵的转速一般在3500～6000rpm，而低压单级离心泵的转速一般在3500rpm以下。因此，中低压单级离心泵一般都带有增速齿轮箱。

The basic structure is similar to the low-pressure single-stage centrifugal pump, and the impeller is installed in the pump cavity. The basic principle of forming medium pressure is to adjust the pressure by increasing the speed of the water pump. The speed of medium and low pressure single-stage centrifugal pump is generally 3500 ~ 6000rpm, while the speed of low-pressure single-stage centrifugal pump is generally below 3500rpm. Therefore, medium and low pressure single-stage centrifugal pumps are generally equipped with speed increasing gear boxes.

工作过程如下：消防车启动后，将水泵转速调4250rpm，泵压头1MPa，水泵处于低压状态；将水速调5150rpm后，泵压头为1.8MPa，泵处于中压状态。由于水泵在某一时刻的转速的，因此中低压单级离心泵和两级离心泵不存在中低压联合工况。

The working process is as follows: after the fire truck is started, adjust the speed of the water pump to 4250rpm, the pump head is 1MPa, and the water pump is under low pressure; After the water speed is adjusted to 5150rpm, the pump head is 1.8MPa and the pump is in the medium pressure state. Due to the speed of the water pump at a certain time, the medium and low pressure single-stage centrifugal pump and the two-stage centrifugal pump do not have the combined working condition of medium and low pressure.

中低压两级离心泵：

Medium and low pressure two-stage centrifugal pump:

结构类似于低压两级离心泵。两级叶轮串联在泵室内的一根轴上。形成介质压力的基本原理是提高泵速或降低流量来改变消防车的运行条件。使电梯达到中压状态。

The structure is similar to the low-pressure two-stage centrifugal pump. Two stage impellers are connected in series on a shaft in the pump room. The basic principle of forming medium pressure is to increase the pump speed or reduce the flow to change the operating conditions of the fire truck. Make the elevator reach the medium voltage state.

中低压串并联离心泵：

Medium and low pressure series parallel centrifugal pump:

主要由叶轮、泵轴、泵壳、前、中、后盖、进水阀、换向阀等组成。两个叶轮各有一个独立的进水室，二级叶轮的合流出口为始终与泵的出水口相连。腔室连通。这样，一级叶轮和第二级叶轮可以串联或并联供水。

It is mainly composed of impeller, pump shaft, pump casing, front, middle and rear covers, water inlet valve, reversing valve, etc. The two impellers each have an independent water inlet chamber, and the confluence outlet of the second stage impeller is always connected with the water outlet of the pump. The chamber is connected. In this way, the first stage impeller and the second stage impeller can supply water in series or in parallel.

切换阀和进水阀是消防车中低压离心泵的两个关键环节。当切换阀处于串联位置时，初级叶轮的压力水进入次级叶轮的进水腔，阀门在压力作用下关闭。将泵置于串联供水状态。当切换阀处于平行位置时，一级叶轮和二级叶轮同时从吸水管吸水，阀门负压开启，两叶轮处于平行状态供水。

Switching valve and water inlet valve are two key links of low-pressure centrifugal pump in fire truck. When the change-over valve is in the series position, the pressure water of the primary impeller enters the water inlet chamber of the secondary impeller, and the valve is closed under pressure. Put the pump in series water supply. When the switching valve is in the parallel position, the first stage impeller and the second stage impeller absorb water from the suction pipe at the same time, the valve is opened under negative pressure, and the two impellers are in the parallel position?? Status water supply.

在泵的中盖上安装有水环导流泵，以满足低压泵排气导流的要求。

A water ring diversion pump is installed on the middle cover of the pump to meet the requirements of exhaust diversion of the low-pressure pump.

中低压系列离心泵：

Medium and low pressure series centrifugal pump:

川消中低压系列离心泵由两个独立的泵室组成，一个是低压泵室，一个是中压泵室。进入中压泵，冷却轴封装置，在中压泵室和低压??泵室之间设置回水管路，使少量液体在低压泵和中压泵之间循环，防止泵体过热，也增加了体积损失。

Chuanxiao medium and low pressure series centrifugal pump consists of two independent pump rooms, one is low pressure pump room and the other is medium pressure pump room. Enter the medium pressure pump, cool the shaft seal device, and install it in the medium pressure pump chamber and the low pressure pump chamber?? The return water pipeline is set between the pump rooms to make a small amount of liquid circulate between the low-pressure pump and the medium-pressure pump, so as to prevent the pump body from overheating and increase the volume loss.

两个泵室通过配备有中低压切换阀的导管连接。在低压工况下，中低压切换阀关闭，低压泵工作，中压泵空转，形成低压供水状态。在中压工况下，打开中低压切换阀，低压离心泵的液流通过导管进入中压离心泵，由中压泵再次加压后从介质中流出压力出水口。可实现中低压并用。

The two pump chambers are connected by a conduit equipped with a medium and low pressure switching valve. Under low-pressure conditions, the medium and low-pressure switching valve is closed, the low-pressure pump works, and the medium-pressure pump idles, forming a low-pressure water supply state. Under the medium pressure working condition, open the medium and low pressure switching valve, the liquid flow of the low pressure centrifugal pump enters the medium pressure centrifugal pump through the conduit, and then flows out of the pressure outlet from the medium after being pressurized again by the medium pressure pump. Medium and low voltage can be used simultaneously.

以上就是介绍的关于中低压消防泵主要有四种结构类型问题的内容了，您可以关注我们网站www.cx-fire.com来查看更多设备的使用或者其他方面的内容。

The above is the content about the four main structure types of medium and low pressure fire pumps. You can follow our website www.cx-fire Com to see more about the use of devices or other aspects.