The pump transmits the mechanical energy or other external energy of the prime mover to the liquid to increase the liquid energy, which is mainly used to transport the liquid including water, oil and acid-base liquid. Pumps are divided into different categories according to different conditions, and each pump has its own unique method of use. Now we will explain why the centrifugal pump to close the valve start, and axial flow pump to open the valve to start. The reasons are as following:
1.Centrifugal pump power performance curve is a slow rise of the approximate straight line, the minimum shut-off power, in order to start and stop light load, solid start and shut down before shutting down the first outlet valve;
2.The axial pump power performance curve is a rapid decline of the convex convex parabola, the maximum power to turn off the death, in order to avoid wrong operation caused serious overloading of the power machine, axial pump pumping device does not allow any valve.
(1) To ensure smooth flow of the pump, good lubrication.
(2) Submersible pump pressure, flow stability, normal temperature in all parts, no high temperature, current stability.
(3) Pump runs smoothly without abnormal vibration, noise and so on.
(4) Stable operation within the range specified on the nameplate performance index.
Some manufacturers will have some very special requirements for their own pumps. Then it is in the procurement, there may be a certain demand for high temperature. If the use of the process, 300 degrees or so there is no way to use the temperature, then he for the overall production, may not play a big role. So some of the production enterprises, in the process of submersible sewage pump procurement process, the most need to take into account the problem is its high temperature performance.
In fact, we will find that this equipment in the production and processing, because it can use a different material for production, and he has a lot of accessories, in the production process, you can also use some very high temperature materials, So we buy it, as long as their choice of this production material, it has a certain high temperature resistance, then buy their own back to the sewage pump, it can have a certain high temperature function.
So in the process of buying the submersible pump, as long as all of his materials can be high temperature, then it is in the course of the use of high temperature effect. Enterprises in the procurement, you can be very confident to buy it, to ensure that the use of the latter part of the process, there will be no security problems occur.
There is a certain use of technical requirements in the use of stainless steel multi-stage pump , if not according to the technical requirements of the manufacturer, the use will have a failure.
1.Such as in the pump installation, can not be installed according to the installation instructions correctly, resulting in vibration pump, so that the mechanical seal end of the pump fit is not good enough, or make the end face to open a fault, so that leakage of the seal.
2.Stainless steel multi-stage centrifugal pump operation due to exhaust is not sufficient or other reasons to make the gas inside the sealed cavity, running in the sealed chamber under the action of pressure, so that the moment caused by friction pairs of sealing leakage failure.
3.The circulatory system is not clean or clean filter is not clean, poor water quality, foreign body, sludge, etc., so that friction surface wear can also cause serious failure.
4.In the stainless steel multi-stage centrifugal pump running due to sudden pressure fluctuations, resulting in pulse pressure or frequent start may make the transmission parts, anti-rotation parts of the weak links damage, resulting in mechanical seal failure. Therefore, the user to use the high-pressure boiler to the pump first to solve the correctness of the power plant process, in the process of running to minimize pressure fluctuations, reduce the number of frequent start. In addition, in the design of the mechanical seal to consider the wear torque from the transmission ring to the shaft and from the static ring to the pump stator and the starting force from the shaft to the transmission ring on the transmission system when the strength of the calculation and selection to avoid Produce the above problems.
Coupling of the transformation. After comparison, the coupling was improved. And the positioning of the half-ring with the positioning of the shaft, the shaft is driven by the key, half-card ring and up and down the axis to match, to ensure that the upper and lower axis positioning, the upper and lower shaft axial size can be through the fit The radial dimension of the shaft is mainly ensured by the coupling accuracy of the sleeve and the upper and lower shafts and the axial positioning of the retaining ring, as shown in Fig. This is a better method of jointing, reducing the length of the rotor, limiting the verticality, strong, eliminating the rotor up and down the movement problem, improve the stability of the operation. Reconstruction of the middle of the pump. After accounting, we put the liquid pump liquid from the original length of 3600mm to 3000mm shortened, shortening each segment 200mm, support spacing reduced, greatly improving the rigidity of the rotor, the hub of the rotor Ye Lun found pendulum is 0.45 ~ 0.7mm, the guide satisfies Bearing on the deflection angle requirements. In order to ensure that the depth of the suction in the same, in the suction port to increase the length of the suction pipe. Increase throttle device. Add a long throttling bushing behind the impeller to reduce the pressure behind the impeller and open four ¢ 50mm holes in the support tube to increase the leakage of the media at the support tube.
Submersible sewage pump in the field of ore applications more and more popular, in order to apply different environmental requirements, production processes, product performance, also need to have a new upgrade. The future, mine submersible sewage pump will move in what direction?
1. Technological innovation will lead the new technology, new materials continue to mine submersible sewage pump production in the use. For example, the traditional casting process to more advanced stainless steel stamping welding process development. Stainless steel stamping welding multi-stage pump core components using stainless steel sheet, with die stamping, with high reliability, good sealing, high precision, its hydraulic performance and pump efficiency is generally better than the casting process production of submersible sewage pump , Stainless steel stamping welding process is mine submersible sewage pump future development trend.
2. Design to more efficient, energy saving, environmental protection direction. For example, oil-filled motors are designed to develop environmentally friendly water-filled motors. Oil-filled submersible motor cavity filled with medium for the mechanical oil, and water-filled submersible motor cavity filled with water, one of its advantages is zero pollution of water, more environmentally friendly. In addition, with the frequency conversion technology in the application of motor design gradually popular, the future mine submersible sewage pump will be more efficient, energy saving.
3. Integral design to the development of removable modular design, that is, motor and pump parts and other modular combination to facilitate the disassembly and replacement of damaged parts, to extend the life of the pump, reducing the use of cost purposes.
Mine submersible sewage pump in foreign countries also has a broad market, but also need to ZTE water production enterprises to actively improve product performance, enhance the application effect, for the depth of overseas markets to fully prepared.
Submersible sewage pump, the pump uses a half-open new impeller, the pump efficiency can be increased by 30%. Beautiful appearance, small size, light weight, large flow, over-current part of the suction structure, strong sewage capacity, not because of small solid Particles or fibrous inhalation, and will not be damaged prematurely by the inhalation of abrasive media. The overall structure of the pump is simple, easy loading and unloading and maintenance. It is absolutely safe and reliable in the working surface containing gas and coal dust, and the silencers with independent intellectual property rights in the exhaust port have greatly improved the conditions of underground construction condition.
Structural features: Pneumatic motor part: by the rotor, leaves, cylinder, shell, upper and lower cylinder head, roof and other components. The rotor has four uniform distribution of the radial groove, slot with the blade, the upper and lower cylinder head each have a blown eye, the air pump starts, the high pressure gas from the inflatable eye to open the leaves of the leaves, while a large number of High pressure gas from the main duct into the cylinder, pushing the blade, driving the rotor rotation work. In the bottom of the shell with a sealed cavity, cavity with a gas ring, the water separated, the use of gas and water pressure, so that the ring rose, enhance the sealing effect.
Start deep well submersible pump, should be smooth rotation, no vibration and abnormal sound, observe the motor running current and line voltage before and after the start of any significant fluctuations. Pay attention to the first installation or maintenance after the operation of the submersible pump, test machine can only start on the ground in order to observe, if found submersible pump abnormalities, should immediately stop, check the direction of rotation is correct, the installation is appropriate, find the reasons after troubleshooting run. Lifting should pay attention to protect the cable to prevent damage, the lifting device (such as tripod, hoist or electric hoist, etc.) should be greater than the weight of the submersible pump, and leave enough room. Before the hanging of the artificial rotation of the impeller to check whether the rotation is flexible, the main contactor contact contact is good, cable and cable joints with or without rupture, abrasion marks, motor shell grounding is reliable, and check the three-phase circuit with a multimeter line conduction.
The flow of liquid is maintained by the energy gradient. When the flow is reduced to near zero, the impeller may increase the peripheral velocity around the inlet due to the action of the inertial force of the liquid, so that the energy near the wall increases, which keeps the liquid flowing The energy slope necessary for the flow of the line no longer exists, so that the flow near the impeller inlet is reversed. The centrifugal pump head is constant for a given impeller diameter and flow, whereas the moving head is a function of the flow. At some point on the head flow curve, once the lift head exceeds the centrifugal head, then the pressure gradient at these points , Resulting in the opposite direction of flow, that is, the phenomenon of reflow.
General centrifugal pump to set the return line, one can act as the minimum return line, when the user flow is less than the rated flow of 30% of the pump, the role of the protection of the pump; Second, the tank of material flow, Some places have dead zones, material aggregation, precipitation, deterioration and so on.
If there is no safety valve, blindly raise the temperature of the magnet wire, such as 180 ℃, 200 ℃, or even 240 ℃, the probability of explosion will be higher. This is because the winding temperature is getting higher and higher, it will produce saturated steam to provide higher temperature, more heat, will lead to higher and higher vapor pressure, but increased the risk of explosion.
If there is no safety valve, must not simply use the method to improve the temperature of the wire temperature.
In the field, once the concentration of sand is too high, the winding will heat over limit, the electromagnetic wire will quickly aging. After the sediment row, due to “overload injury”, the motor thermal load capacity will be greatly reduced, often in the back row of water, the winding short-circuit breakdown, causing the motor explosion. It is this explosion in the water illusion, confused people, for many years, can not find the reasons for the explosion of submersible pumps.