"Fire Equipment" Common Fire Pump Structural Principles

1 , low pressure fire pump

2 , medium and low pressure fire pump

3 , high and low pressure fire pump (multi-stage centrifugal pump, centrifugal vortex pump)

Focus on the introduction of various pumps and their structural principles and technical parameters

First, low pressure fire pump

(one)   Single-stage centrifugal pump structure principle ( BD50 )

1 impeller

2 , pump casing

3 , the pump shaft

4 , shaft sealing device

5 , water diversion device

Single-stage centrifugal pump structure

(two)   The principle of the two-stage centrifugal pump ( BS30 , BS60 )

1 impeller

The BS30 pump has two impellers that are “back-to-back” aligned and set on the pump shaft to automatically balance the axial force. Components: The front cover, back cover, blades and other components. The general impeller has 6 to 8 blades. The front cover and back cover of the impeller form a certain chamber inside the impeller. When the water flow from the front cover into the center of the impeller, through the impeller rotation, the centrifugal force, the water flow is thrown around the radial direction, increasing its pressure energy and kinetic energy.

2 , pump casing

The pump casing is composed of two parts: a press chamber and a suction chamber. The role of the suction chamber is to introduce the liquid in the suction pipeline to the impeller with minimum loss. The BS30 pump adopts a conical suction chamber. The suction chamber has a simple structure and can cause little acceleration before the inlet of the impeller.

The main function of the extrusion chamber is to collect the high-speed liquid thrown from the impeller with minimal loss and lead it to the secondary impeller and discharge outlet. The BS30 pump uses a radial guide vane structure.

3 , the pump shaft

The impeller, bushing and other parts are mounted on the pump shaft. One end of the shaft is supported by the sliding bearing, and the other end is connected to the power output shaft which drives the impeller to rotate by a flange coupling.

4 、 Water diversion device

The water diverting device of the BS30 pump is completed by a water ring pump mounted on the same pump shaft as the centrifugal impeller.

(two)    Low pressure fire pump parameters

(three)   Low pressure centrifugal pump features

1. The structure is simple, easy to manufacture and cheap.

2. Easy to use and easy to maintain.

3. Has a certain head, can provide a larger flow, to meet the general needs of the fire.

4. Suitable for use with mobile fire pumps or fire engines.

Second, the low pressure fire pump

(one)   The structure of the low-pressure fire pump

The low-pressure fire pump is also called a series-parallel centrifugal fire pump. It is mainly composed of an impeller, a pump shaft, a pump casing, a front cover, a middle cover, an inlet valve, a reversing valve, a mechanical seal device, and a water diversion device. (By BCB40 as an example)

Low-pressure fire pump structure

1 , impeller?

The BCB40 pump has two impellers mounted opposite each other on the pump shaft.

Each of the two impellers has a separate inlet chamber, and the confluence of the impeller (2) always communicates with the outlet of the pump , and the confluence of the impeller (1) can communicate with the outlet of the pump or the impeller (2). The inlet chamber communicates. In this way, the impeller (1) and the impeller (2) can be connected in series and can also be supplied in parallel.

2 , pump casing and pump cover

The pump casing cooperates with the front cover and the middle cover of the pump to form a certain chamber inside the pump, creating conditions for the change of working conditions of the two impellers.

Both sides of the pump casing are provided with suction pipes, in which the inlet chamber of the impeller (1) and impeller (2) are separated at the end of the suction pipe, and the suction pipe port connected with the impeller (2) is provided with Water valve. An outlet pipe is arranged on the right side of the pump casing, and a switching valve is arranged on the pipe. The rotation of the valve core can set two working states of the pump: making the confluence outlet of the impeller (1) communicate with the outlet pipe and the impeller (2) The suction chambers are separated by two parallel impellers.

Low-pressure fire pump in parallel working state

The confluent outlet of the impeller (1) is separated from the outlet pipe and communicates with the suction chamber of the impeller (2) , causing the two impellers to supply water in series.

Mechanical shaft seals are installed in the front cover and the middle cover of the pump.

Low-pressure fire pump in series working state

3 , switch valve and inlet valve

The switch valve and the inlet valve are the two key steps of the low-pressure fire pump. When the switch valve is in the series position, the pressure water of the impeller (1) enters the inlet chamber of the impeller (2) and closes the valve under pressure. Make the pump in series water supply. When the switch valve is in the parallel position, the impeller (1) and the impeller (2) simultaneously absorb water from the suction pipe, the valve opens under negative pressure, and the two impellers are in parallel water supply.

4 、 Water diversion device

In the middle cover of the pump, a water ring pump is installed to meet the requirements of the low and medium pressure pump exhaust water diversion. The water ring pump and the low-pressure fire pump use the same pump shaft.

(II) Technical parameters of medium and low pressure fire pumps   ( BCB40 )

(III) Characteristics of medium and low pressure fire pumps

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

The medium and low pressure water supply system consisting of medium and low pressure fire pumps has a rapid fire field, flexible operation in complex high-rise buildings and underground buildings, and has the ability to fight various oil fires and supply water to the upper part of high-rise buildings. Large, long-range characteristics.

(D), the application of low pressure fire pump test

1. Remote water supply

2. High-level water supply

Fifth, the application prospects of low pressure fire pump

Third, high and low pressure centrifugal pump

The high and low pressure water pumps are mainly composed of an atmospheric shell, a high pressure shell, an impeller, a pump shaft, a diffuser and a stuffing box.

(a) Structure

1 atmospheric pump housing

There is a vacuum gauge on the pressure pump housing, and a water diversion connection for the plunger pump. It also contains a replaceable stuffing box and a grease nipple to relubricate the needle roller bearings.

2. Impeller

One-stage normal impeller, three-stage high-pressure impeller, reverse-mounted with normal-pressure and high-pressure impeller, reducing axial thrust.

3. Pump shaft

Made of stainless steel, sealed with a special stuffing box.

4. Water diversion device

Piston pump diversion, V-belt tensioning device.

5. Select valve     Atmospheric pressure - atmospheric pressure / high pressure

A selection valve is installed between the atmospheric and high pressure parts of the pump.

A high pressure foam mixing system with optional foam mixing ratios can be connected to the selector valve.

(II) Technical parameters of NH40 pump

(III) Characteristics of High and Low Pressure Fire Pumps

1. It can supply low-pressure and large-flow water independently, and can supply low-pressure and high-pressure water at the same time.

2. It can play an important role in fighting indoor fires, electrical fires, and dust fires in buildings.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.