How to calculate the flow rate and head of Dalian acid resistant pump?

The flow and head calculation of Dalian acid resistant pumps is an important part of selecting and using acid resistant pumps. Correct calculation can ensure efficient operation of the pump under specific working conditions, while avoiding equipment damage or insufficient performance caused by improper selection.

1、 Definition and Calculation of Traffic

1. Definition of traffic

Flow rate refers to the volume of liquid passing through a pump per unit time, usually represented by the symbol (Q), in cubic meters per hour (m ³/h), liters per minute (L/min), or cubic meters per second (m ³/s). In the selection of acid resistant pumps, flow rate is an important parameter for measuring the pump's conveying capacity.

2. Calculation of traffic

The calculation of flow rate is usually based on actual operating conditions, and the specific methods are as follows:

Direct measurement method: In actual operation, the flow rate of the pump can be directly measured through a flow meter.

Theoretical calculation method: Based on process requirements or system design, calculate the flow rate using the following formula: [Q=frac {V} {t}], where:

(Q) Flow rate (m ³/h or L/min);

(V) For liquid volume (m ³ or L);

(t) For time (h or min).

System Requirements Method: Determine the flow rate based on the liquid transportation requirements of the process system. For example, in chemical production, the flow rate is calculated based on the feed rate of the reactor or the emptying time of the storage tank.

3. Precautions for traffic calculation

Medium characteristics: Acid resistant pumps are usually used to transport corrosive liquids, and the influence of medium density, viscosity, and corrosiveness on flow rate needs to be considered.

Pipeline resistance: Pipeline length, bends, valves, etc. can increase system resistance and may affect actual flow rate.

Safety factor: When calculating flow, it is recommended to reserve a safety margin of 10% to 20% to cope with possible changes in operating conditions.

2、 Definition and Calculation of Head

1. Definition of head

Head refers to the height or ability of a pump to lift liquid or overcome resistance, usually represented by the symbol (H) and measured in meters (m). Head includes static head (liquid lifting height) and dynamic head (energy required to overcome pipeline resistance).

2. Calculation of head

The calculation of head needs to consider the height difference of liquid transportation and the resistance of the pipeline system. The specific methods are as follows:

Static head calculation: [H_ {text {static}}=h2-h1], where:

(H_ {text {static}}) is the static head (m);

(h1) is the liquid level height at the pump inlet (m);

(h2) is the liquid level height at the pump outlet (m).

Calculation of dynamic head: Dynamic head mainly includes pipeline frictional resistance and local resistance, usually calculated by the following formula: [H_ {text {dynamic}}=frac {v ^ 2} {2g}+sumxifrac {v ^ 2} {2g}+lambda frac {L} {D}frac {v ^ 2} {2g}] Among them:

(H_ {text {dynamic}}) is the dynamic head (m);

(v) For liquid flow velocity (m/s);

(g) Acceleration due to gravity (9.81m/s ²);

(xi) is the local resistance coefficient (such as elbows, valves, etc.);

(lambda) is the friction coefficient of the pipeline;

(L) For pipeline length (m);

(D) The diameter of the pipeline (m).

Total head calculation: [H=H_ {text {static}}+H_ {text {dynamic}}]

3. Precautions for head calculation

Medium density: The calculation of head is based on liquid density, and conversion is required for media of different densities.

Pipeline layout: Complex pipeline layout will increase local resistance and requires accurate calculation.

Pump efficiency: The actual head may decrease due to the efficiency of the pump, and the performance curve of the pump needs to be considered.

3、 The relationship between flow rate and head

Flow rate and head are two key parameters of pump performance, and there is a certain relationship between the two, usually represented by the pump's performance curve. When selecting, it is necessary to ensure that the flow rate and head of the pump can meet the actual working conditions, while avoiding operation in low efficiency areas.

1. Performance curve

The performance curves of a pump include flow head curve, flow efficiency curve, and flow power curve. Through the performance curve, the head and efficiency of the pump at a specific flow rate can be determined.

2. Matching of working conditions

In practical applications, it is necessary to select appropriate operating points in the performance curve based on the flow and head requirements of the system. For example, in chemical production, if the flow demand is 50m ³/h and the head demand is 30m, it is necessary to choose a pump that operates efficiently near this operating point.

The flow rate and head calculation of acid resistant pumps are the basis for selection and use, and accurate calculations should be made based on actual working conditions, medium characteristics, pipeline resistance, and system layout. During the calculation process, the following points should be noted:

Flow calculation needs to consider the characteristics of the medium and system requirements, and reserve a safety margin.

The calculation of head requires comprehensive consideration of static head and dynamic head to accurately evaluate pipeline resistance.

When selecting, it is necessary to match the performance curve of the pump to ensure efficient operation.

Through scientific calculations and reasonable selection, the stability and reliability of acid resistant pumps in the transportation of corrosive liquids can be ensured, the service life of equipment can be extended, and operating costs can be reduced.