（1） Structural principle of medium and low pressure fire pump

中低压消防泵也称为串并联离心消防泵，它主要由叶轮、泵轴、泵壳、前盖、中盖、进水活门、换向阀、机械密封装置、引水装置等组成。（以BCB40为例）

Medium and low pressure fire pump is also called series parallel centrifugal fire pump. It is mainly composed of impeller, pump shaft, pump shell, front cover, middle cover, water inlet valve, directional valve, mechanical sealing device, water diversion device, etc. (take bcb40 as an example)

中低压消防泵的结构

Structure of medium and low pressure fire pump

1、叶轮蕌

1. Leaf whorl

BCB40泵有两个叶轮，它们相对地安装在泵轴上。

Bcb40 pump has two impellers, which are relatively installed on the pump shaft.

两个叶轮各有单独的进水腔室，而叶轮(2)的汇流出口始终与泵的出水口相通，叶轮(1)的汇流出口既可与泵出水口相通，也可与叶轮(2)的进水腔室相通。这样叶轮(1)和叶轮(2)则可串联供水，也可并联供水。

The two impellers have separate water inlet chambers, and the confluence outlet of the impeller (2) is always connected with the water outlet of the pump. The confluence outlet of the impeller (1) can be connected with both the water outlet of the pump and the water inlet chamber of the impeller (2). In this way, the impeller (1) and the impeller (2) can supply water in series or in parallel.

2、泵壳与泵盖

2. Pump casing and pump cover

泵壳与泵的前盖、中盖相配合，使泵内形成一定腔室，为两个叶轮的工况变化创造条件。

The pump casing is matched with the front cover and middle cover of the pump to form a certain chamber in the pump and create conditions for the change of working conditions of the two impellers.

泵壳的水平两侧均设有吸水管，其中叶轮(1)和叶轮(2)的进水腔室在吸水管端部相隔开，并且与叶轮(2)相连的吸水管端口设有进水活门。泵壳的右侧设有出水管，管上设有转换阀，其阀芯的转动可设定泵两种工作状态：使叶轮(1)的汇流出口与出水管相通，且与叶轮(2)的吸水腔室相隔造成两个叶轮并联供水。

The horizontal sides of the pump shell are provided with suction pipes, in which the water inlet chambers of the impeller (1) and the impeller (2) are separated at the end of the suction pipe, and the port of the suction pipe connected with the impeller (2) is provided with a water inlet valve. A water outlet pipe is arranged on the right side of the pump shell, and a change-over valve is arranged on the pipe. The rotation of the valve core can set two working states of the pump: the confluence outlet of the impeller (1) is connected with the water outlet pipe and separated from the water suction chamber of the impeller (2), resulting in the parallel water supply of the two impellers.

中低压消防泵并联工作状态

Parallel working state of medium and low pressure fire pumps

使叶轮(1)的汇流出口与出水管相隔，且与叶轮(2)的吸水腔室相通，造成两个叶轮串联供水。

The confluence outlet of the impeller (1) is separated from the water outlet pipe and connected with the water suction chamber of the impeller (2), resulting in two impellers supplying water in series.

泵的前盖和中盖内均设有机械式轴封装置。

Mechanical shaft sealing devices are set in the front cover and middle cover of the pump.

中低压消防泵串联工作状态

Working state of medium and low pressure fire pump in series

3、转换阀与进水活门

3. Change over valve and inlet valve

转换阀与进水活门是中低压消防泵的两个关键环节，转换阀处于串联位置时，叶轮(1)的压力水进入叶轮(2)的进水腔室，并在压力下将活门关闭，使泵处于串联供水状态。当转换阀处于并联位置时，叶轮(1)与叶轮(2)同时由吸水管中吸水，活门在负压下开启，两个叶轮处于并联供水状态。

The change-over valve and the water inlet valve are two key links of the medium and low pressure fire pump. When the change-over valve is in the series position, the pressure water of the impeller (1) enters the water inlet chamber of the impeller (2), and the valve is closed under pressure to make the pump in the series water supply state. When the change-over valve is in the parallel position, the impeller (1) and the impeller (2) absorb water from the suction pipe at the same time, the valve opens under negative pressure, and the two impellers are in the parallel water supply state.

4、引水装置

4. Water diversion device

在泵的中盖上，安装有水环引水泵，以满足中低压泵排气引水的要求。水环泵与中低压消防泵使用同一泵轴。

A water ring diversion pump is installed on the middle cover of the pump to meet the requirements of exhaust and diversion of medium and low pressure pumps. The water ring pump and the medium and low pressure fire pump use the same pump shaft.

（三）、中低压消防泵的特点

（3） Features of medium and low pressure fire pumps

既可以提供低压大流量水流，亦可提供中压水流。

It can provide both low-pressure and large flow water flow and medium pressure water flow.

由中低压消防泵为核心组成的中低压供水系统具有火场展开迅速，在复杂的高层建筑、地下建筑内部作战机动灵活，具有扑救各种油类火灾和向高层建筑上部供水的能力、具有流量较大、射程较远的特点。

The medium and low pressure water supply system composed of medium and low pressure fire pumps has the characteristics of rapid fire spread, flexible operation in complex high-rise buildings and underground buildings, the ability to put out all kinds of oil fires and supply water to the upper part of high-rise buildings, large flow and long range.

（四）、中低压消防泵的应用试验

（4） Application test of medium and low pressure fire pump

1.远距离供水情况

1. Remote water supply

2.高层供水情况

2. High rise water supply

五、中低压消防泵的应用前景

5、 Application prospect of medium and low pressure fire pump

三、高低压离心泵

3、 High and low pressure centrifugal pump

高低压水泵主要由常压外壳、高压外壳、叶轮、泵轴、扩散器和填料箱组成。

The high and low pressure water pump is mainly composed of atmospheric pressure shell, high pressure shell, impeller, pump shaft, diffuser and stuffing box.

以上就是今天带给大家的知识,川消专注行业多年，为用户不断的提供有价值的内容，更多内容请继续关注我们：http://www.cx-fire.com

The above is the knowledge brought to you today. Sichuan consumer has focused on the industry for many years and continuously provided users with valuable content. Please continue to pay attention to us for more content: http://www.cx-fire.com