The application of centrifugal pumps in the drilling fluid cooling system mainly leverages their ability to provide high pressure and large flow rates, ensuring that cooling water can smoothly flow to all the equipment and machinery that require cooling. This helps to maintain the stability of the equipment and process temperatures, ensuring normal operation.
In industrial production, cooling water circulation systems are crucial. Centrifugal pumps can draw cooling water from cooling towers or tanks and then transport it through pipelines to various equipment and machinery that require cooling, such as generator sets, refining units, and chemical reactors. In this way, the heat generated during the operation of the equipment and machinery can be promptly removed, ensuring that their temperatures remain within safe limits. This helps maintain normal operation, improve production efficiency, and also contributes to extending the equipment’s lifespan.
Overall, the application of centrifugal pumps in slurry cooling systems is very extensive. Whether in drilling engineering, infrastructure construction, or other fields, they play an important role in ensuring the stable operation of equipment and processes.
The main working principle of multi-stage centrifugal pump
(1) The impeller is driven by the pump shaft to rotate, the fluid located between the blades to do work, the fluid by the role of centrifugal force, by the impeller centre is thrown to the periphery. When the fluid reaches the periphery of the impeller, the flow rate is very high.
(2) The pump casing collects the liquid thrown out from between the blades, and these fluids flow in the casing in the direction of gradually expanding the worm shell-shaped channel, so that the kinetic energy of the fluid is converted into static pressure energy, reducing energy loss. So the role of the pump casing is not only in the collection of liquid, it is an energy conversion device.
(3) Liquid suction principle: rely on the impeller high-speed rotation, forcing the impeller centre of the liquid at a high speed to be thrown away, thus forming a low pressure in the centre of the impeller, the liquid in the low slot is therefore a steady stream of suction.
Air binding phenomenon
Gas binding phenomenon: If the multi-stage centrifugal pump is filled with gas in the casing before startup, the impeller centre gas can not be thrown after startup to form a large enough vacuum in the place, so that the liquid in the groove can not be sucked on. This phenomenon is called air binding. In order to prevent the occurrence of gas binding phenomenon, multi-stage centrifugal pumps to start before the pump casing with external liquid to fill the space. This step of the operation is called filling the pump. In order to prevent the liquid filled into the pump casing from flowing into the low slot due to gravity, the inlet of the pump suction line is equipped with a non-return valve (bottom valve); if the pump position is lower than the liquid level in the slot, then the startup
There is no need to fill the pump.
The guide wheel is installed at the periphery of the impeller, so that the energy conversion efficiency of the liquid in the pump is high. The guide wheel is a fixed ring with blades located around the impeller. The bending direction of these blades is opposite to that of the impeller blades, and the bending angle is exactly in line with the direction of the liquid outflow from the impeller, which guides the liquid to change direction smoothly in the pump casing channel and minimises energy loss, and the efficiency of converting the dynamic pressure energy into static pressure energy is high.
The balance hole on the back cover plate eliminates axial thrust. Leaving the impeller periphery of the liquid pressure has been higher, a part of the impeller will seep into the impeller after the cover plate back side, while the impeller front side of the liquid inlet is low pressure, thus generating the impeller pushed to the pump inlet side of the axial thrust. This is likely to cause wear at the contact between the impeller and the pump casing, and in severe cases, vibration will also be generated. Balance hole so that part of the high-pressure liquid leakage to the low-pressure area, to reduce the pressure difference between the impeller before and after. But this will also cause a reduction in pump efficiency.
Centrifugal pump working principle
Driving machine through the pump shaft driven impeller rotation generates centrifugal force, under the action of centrifugal force, the liquid along the vane runner is thrown to the impeller outlet, the liquid is collected by the worm casing and sent to the discharge pipe. Liquid from the impeller to obtain energy, so that the pressure and speed energy are increased, and rely on this energy to transport the liquid to the workplace.
In the liquid is thrown to the impeller outlet at the same time, the impeller inlet to the centre of the formation of a low-pressure, in the suction tank and the impeller centre of the liquid between the pressure difference arises, suction tank in the liquid in the pressure difference under the action of the suction pipeline and the pump suction chamber into the impeller continuously.
Second, the structure of the centrifugal pump and the main parts
A centrifugal pump is mainly composed of pump body, impeller, sealing ring, rotating shaft, shaft sealing box and other components, some centrifugal pumps are also equipped with a guide wheel, induced wheel, balanced discs and so on.
1. Pump body: that is, the pump casing, including the suction chamber and pressure chamber.
① suction chamber: its role is to make the liquid flow evenly into the impeller.
② pressure chamber: its role is to collect the liquid, and send it to the next impeller or guided discharge pipe, while reducing the speed of the liquid, so that the kinetic energy further into the pressure energy. Pressure liquid chamber has two forms of worm shell and guide leaf.
2. Impeller: it is the only element in the centrifugal pump that transmits energy to the liquid, the impeller is fixed on the shaft with a key, rotates with the shaft driven by the prime mover, and transmits the energy of the prime mover to the liquid through the vanes.
Impeller classification.
① according to the liquid inflow classification: single suction impeller (in one side of the impeller has an inlet) and double suction impeller (liquid from both sides of the impeller symmetrically flow into the impeller channel).
② in accordance with the liquid flow direction relative to the axis of rotation classification: runoff impeller, axial impeller and mixed flow impeller.
③ in accordance with the structure of the impeller form classification: closed impeller, open impeller and semi-open impeller.
3. Shaft: an important part of the transmission of mechanical energy, the torque of the prime mover through it to the impeller. Pump shaft is the main part of the pump rotor, the shaft is equipped with impellers, bushings, balance disc and other parts. The pump shaft is supported by the bearings at both ends and rotates at a high speed in the pump, thus the pump shaft should have a large bearing capacity, wear and corrosion resistance. Pump shaft materials are generally selected carbon steel or alloy steel and tempered.Seal ring: is installed in the rotation of the impeller and static pump casing (in the middle and guide vane of the combination) between the sealing device. Its role is to control the gap between the two methods to increase the pump between the high and low pressure chamber of the liquid flow resistance, reduce leakage.Shaft sleeve sleeve is used to protect the pump shaft, so that it is not subject to corrosion and wear. If necessary, the sleeve can be replaced. Shaft seal pump shaft and front and rear end caps between the stuffing box device referred to as the shaft seal, mainly to prevent the pump from liquid leakage and air into the pump, in order to achieve the purpose of sealing and preventing air intake caused by pump cavitation.The form of shaft seal: rubber seal with skeleton, packing seal and mechanical seal.Balancing device for axial force.
Centrifugal pump’s main working parameters
1. Flow: that is, the pump discharged in a unit of time the amount of liquid, usually expressed in volume units, the symbol Q, the unit has m3 / h, m3 / s, l / s, etc., and so on.
2. head: conveying a unit weight of liquid from the pump inlet (pump inlet flange) to the pump outlet (pump outlet flange), the value-added energy, expressed in H, the unit is kgf.m/kgf.
3. rotational speed: pump speed is the number of pumps rotating per minute, with N to indicate. Motor speed N generally in 2900 rpm or so.
4. Cavitation margin: centrifugal pump cavitation margin is the main parameter of the performance of the pump, with the symbol Δhr, expressed in metres of liquid column.
5. Power and efficiency: pump input power for the shaft power N, that is, the output power of the motor. Pump output power for the effective power Ne.
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