Fire pump technical articles and analysis of various failures

As the name suggests, fire pumps are divided into different types according to different classification methods. They are widely sealed, leak-free and corrosion-resistant. They are widely used in environmental protection, water treatment, fire protection and other departments to pump various liquids. Is creating a leak-free, pollution-free

The ideal pumping type for civilized workshops and civilized factories is similar to that of fire-fighting systems, except that the head and flow are different. The selection criteria of the fire pump should be considered in five aspects according to the process flow and water supply and drainage requirements.

Classification of fire pumps:

First, according to whether there is a power source can be divided into:

a non-power source fire pump (referred to as pump);

b fire pump group (referred to as pump group);

Second, the non-powered fire pump can be classified according to the following rules:

1. According to the use occasion can be divided into:

a vehicle fire pump;

b marine fire pump;

c engineering fire pump;

d Other fire pumps.

2. According to the export pressure level, it can be divided into:

a low pressure fire pump

b medium pressure fire pump

c medium and low pressure fire pump

d high pressure fire pump

e high and low fire pump

3. According to the use can be divided into:

a Water supply fire pump

b Regulated fire pump

c for foam liquid fire pump

4. According to the auxiliary features can be divided into:

a ordinary fire pump

b deep well fire pump

c diving fire pump

Third, the fire pump group can be classified according to the following rules:

1. According to the power source form can be divided into:

a Diesel engine fire pump set

b motor fire pump set

c gas turbine fire pump set

d Gasoline engine fire pump set

2. According to the use can be divided into

a Water supply fire pump unit

b Regulated fire pump set

c hand lift mobile fire pump set

3. According to the auxiliary characteristics of the pump group can be divided into:

a ordinary fire pump unit

b deep well fire pump unit

c diving fire pump set

4. The above is the basic classification, but the various types can be combined with each other, such as medium and low voltage fire pumps, high and low pressure vehicle fire pumps, ordinary fire pump sets, electric diving fire pump sets, etc.

Fire pump model:

1. The model of the non-powered fire pump consists of five parts: the pump characteristic code, the main parameter, the use feature code, the auxiliary feature code and the enterprise custom code. Its composition is as follows:

Defined as follows (in order):

Pump feature code

Main parameter

Use feature code

Auxiliary feature code

Enterprise custom code

For example: the meaning of fire pump XQB3.3/30-125-160

XQB is a representative of fire rated water supply equipment

3.3——0.33MPa

30——30L/S

125——Pipe inlet and outlet diameter (mm)

160——nominal diameter of the impeller (mm)

Model of the fire pump group:

The model of the fire pump group consists of six parts: pump characteristics, pump group feature code, main parameters, use feature code, auxiliary feature code and enterprise custom code. Its composition is as follows:

Defined as follows (in order):

Pump feature code

Pump set feature code

Main parameter

Use feature code

Auxiliary feature code

Enterprise custom code

2.3 The representation of each feature code is shown in Table 1.

Table 1

Feature code

Pump characteristics

Vehicle fire pump CB

Marine fire pump HB

Hand lift mobile fire pump set JB

Engineering fire pump XB

Other fire pump TB

Pump set characteristics

Diesel engine C

Motor D

Gas turbine R

Gasoline engine Q

Main parameters (pressure / flow) 10 × rated pressure / rated flow

Use characteristics

Voltage regulator W

Water supply G

Foaming liquid P

Auxiliary feature

Deep well pump J

Submersible pump Q

Ordinary pump omitted

2.4 The rated pressure in the main parameters is MPa, and the rated flow unit is L/s.

2.5 In the model preparation, for multi-purpose products, the use characteristics may not be marked.

2.6 Model examples are as follows

a Engineering fire pump, rated pressure is 0.78MPa, rated flow is 20L/s, its model is XB7.8/20

b High and low pressure vehicle fire pump, high pressure rated pressure is 4.0MPa, low pressure rated pressure is 1.0MPa, high pressure rated flow is 6L/s, low pressure rated flow is 40L/s, its model is CB40 10/6 40

c Deep-water fire pump set driven by diesel engine with rated pressure of 0.85MPa and rated flow of 30L/s, its model is XBC8.5/30GJ

d Gasoline engine drive, rated pressure is 0.80MPa, rated flow is 10L / s hand lift mobile fire pump set, its model is JBQ8.0/10

National Standard of the People's Republic of China GB 6245-2006 Fire Pump Fire Pump

Fire pump troubleshooting:

Usually, in the process of maintenance, the diagnosis of fire pump failure is a key link. Several common faults and elimination measures are given below for the purpose of diagnosis of fire pump failure.

1, no liquid supply, insufficient liquid supply or insufficient pressure

1) The pump is not filled with water or is not properly vented

Elimination: Check that the pump casing and inlet lines are all filled with liquid.

2) The speed is too low

Elimination measures: Check if the motor wiring is correct, the voltage is normal or the turbine pressure of the turbine is normal.

3) The system head is too high

Elimination measures: Check the head of the system (especially the friction loss).

4) The suction stroke is too high

Elimination measures: Check the existing net head (the inlet line is too small or too long will cause a large friction loss).

5) Impeller or pipeline is blocked

Elimination measures: Check for obstacles.

6) The direction of rotation is wrong

Elimination measures: Check the direction of rotation.

7) There is leakage in the air or inlet line

Elimination measures: Check the inlet line for air pockets and/or air leaks.

8) The packing or seal in the stuffing box is worn out, causing air to leak into the pump casing.

Elimination measures: Check the packing or seal and replace as needed to check if the lubrication is normal.

9) Insufficient suction head when pumping hot or volatile liquids

Elimination measures: Increase the suction head and consult the manufacturer.

10) The bottom valve is too small

Elimination: Install the correct size bottom valve.

11) The bottom valve or inlet tube is not deep enough

Elimination measures: Consult the manufacturer for the correct immersion depth. Use a baffle to eliminate eddy currents

12) The impeller clearance is too large

Elimination measures: Check that the gap is correct.

13) Impeller damage

Elimination measures: Check the impeller and replace it as required.

14) The impeller diameter is too small

Elimination measures: Consult the manufacturer for the correct impeller diameter.

15) Pressure gauge position is incorrect

Elimination measures: Check that the position is correct and check the outlet nozzle or pipe.

2. The fire pump will stop running after a while:

1) Suction is too high

Elimination measures: Check the existing net head (the inlet line is too small or too long will cause a large friction loss).

2) Impeller or pipeline is blocked

Elimination measures: Check for obstacles.

3) There is leakage in the air or inlet line

Elimination measures: Check the inlet line for air pockets and/or air leaks.

4) The packing or seal in the stuffing box is worn out, causing air to leak into the pump casing.

Elimination measures: Check the packing or seal and replace as needed. Check that the lubrication is normal.

5) Insufficient suction head when pumping hot or volatile liquids

Elimination measures: Increase the suction head and consult the manufacturer.

6) The bottom valve or inlet tube is not deep enough

Elimination measures: Consult the manufacturer for the correct immersion depth and use a baffle to eliminate eddy currents.

7) Damage to the pump casing seal

Elimination measures: Check the gasket and replace it as required.

3. The power consumption of the fire pump is too large:

1) The direction of rotation is wrong

Elimination measures: Check the direction of rotation.

2) Impeller damage

Elimination measures: Check the impeller and replace it as required.

3) Rotating parts are killed

Elimination measures: Check that the clearance of the internal wear parts is normal.

4) Shaft bending

Elimination measures: Straighten the shaft or replace it as required.

5) The speed is too high

Elimination measures: Check the winding voltage of the motor or the steam pressure delivered to the turbine.

6) The head is below the rated value. Pumping too much liquid

Elimination measures: Consult the manufacturer. Install the throttle valve and cut the impeller.

7) Liquid is heavier than expected

Elimination measures: check the specific gravity and viscosity.

8) The stuffing box does not have the correct packing (the packing is not enough, it is not properly inserted or run in, the packing is too tight)

Elimination measures: Check the packing and refill the stuffing box.

9) Incorrect bearing lubrication or bearing wear

Elimination measures: check and replace as required.

10) The running clearance between the wear rings is incorrect.

Elimination measures: Check that the gap is correct. Replace the wear ring of the pump casing and/or impeller as required.

11) The stress on the pipe on the pump casing is too large

Elimination measures: Eliminate stress and consult with the manufacturer. After the stress is removed, check the alignment.

Usually, in the process of maintenance, the diagnosis of fire pump failure is a key link. Several common faults and elimination measures are given below for the purpose of diagnosis of fire pump failure.

Insufficient fluid or insufficient pressure:

1) The pump is not filled with water or is not properly vented

Elimination measures: inspection

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