Different arrangements of stainless steel centrifugal pumps on different occasions
Stainless steel centrifugal pumps have many advantages such as wide range of performance, small size, simple structure, easy operation, and low operating cost. Generally, the flow and pressure of the selected centrifugal pump may be inconsistent with the requirements in the pipeline, or due to changes in production tasks and process requirements, the flow adjustment of the pump is required at this time, which essentially changes the operating point of the centrifugal pump.
The requirements and methods for the arrangement of stainless steel centrifugal pumps are very similar, but as a basis for the stability of stainless steel centrifugal pumps, the knowledge of the layout must be proficient.
First, talk about the arrangement of stainless steel centrifugal pumps, which can be arranged in the open air, semi-open air, or even directly indoors. When it is arranged in the open air, it is generally under or on the side of the pipe gallery, or it can be arranged near the suction equipment, mainly because these locations are well ventilated and easy to operate and maintain.
The reason why the stainless steel centrifugal pump is chosen to be arranged in a semi-open air way is mainly for rainy areas. The pump can be arranged below the pipe gallery and the ceiling can be arranged above the pipeline; or the pump can be arranged on the lower floor of the frame to frame The platform acts as a ceiling.
In some cold and sandy areas, where the process is known to have special requirements, indoor layout is a better choice for stainless steel centrifugal pumps, which can adequately protect the equipment and reduce the adverse effects caused by external environmental factors. influences.
For stainless steel centrifugal pumps arranged in the open air or semi-open air, the axis of the pump and the prime mover should be perpendicular to the axis of the pipe gallery; for indoor pumps, when the temperature of the liquid being transported is higher than the auto-ignition point or the liquid is a liquid hydrocarbon, The other pumps are placed in their own rooms and separated by a firewall.
Moreover, the net distance between the pump end or the pump side and the wall, and the net distance between the two rows of pumps cannot exceed the specified standards. Of course, how to arrange it depends on the specific type and specifications. In short, it is necessary to ensure that the stainless steel centrifugal pump can function normally. Operation, but also to facilitate future inspections and maintenance.
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Ensure that the sewage pump facility is insured, and the company has a sewage pump facility
In order to ensure the operation of the sewage pump facilities, the company has more standard treatment of sewage pump facilities, annual overhaul, monthly secondary maintenance, and once-daily first-level maintenance policy. These ISO9002 quality management are guaranteed sewage pumps. In order to ensure the reliability of safe operation, the high-quality training and improvement of the skills of the operators are required to be implemented. The implementation of these safe operation policies and policies is to ensure the operation of the sewage pump equipment. The guarantee of reliability. The water of the water source is pressed into the heat pipe through the ballistic net under the action of air pressure (or water pressure). After many years of practical work and theoretical simulations, apply the knowledge learned to practical work, rationally arrange the distribution and arrangement of water, and apply the characteristics of each pump to achieve the maximum water output of the pump with the least amount of power. Achieve the best operational statement. Because the abnormal condition of a water pump will affect the network of the entire mountain supply system, it has serious consequences. Long-term high-tech innovation, enter a small amount of money to transform the water purification equipment that was originally left behind.
How to ensure the excellent water supply of the sewage pump, the company has taken a series of measures: mobilizing the rational configuration of the sewage pump equipment, and implementing the best combination of man and machine. The lack of these measures illustrates the rationality of the rational allocation of sewage pump equipment and water purification equipment. Enter funds, retrofit old equipment, old ballistic nets, improve the hydraulic environment, install static mixers, etc. The overflow components of the sewage pump include: a suction chamber, an impeller, and an extrusion chamber. Before the pump is working, the pump body and the heat-dissipating tube must be filled with water to form a vacuum form. When the impeller rotates rapidly, the blade sends water quickly and smoothly, and the swirling water is flying away from the impeller under the action of centrifugal force. After the water is thrown, the center of the impeller integrally forms a vacuum region. Such as: the safest mode of operation, Shanghai’s urban cooling pipeline network is interoperable, there is a company center arrangement room to dominate the water supply pressure in the region, too high to form a burst tube, to the masses, the state to form property losses, water pressure is too low It affects the electricity consumption of the whole user and forms a good abstraction of the enterprise. When it comes to economics, the cost of water for enterprises, including electricity, antimony, chlorine, and ammonia, must dominate the economic activities of enterprises and improve the economy in the safest way of operation, the best arrangement, and the lowest water cost. Benefits, companies have accumulated some experience in this area. The reliability of the safe operation of the sewage pump sewage pump equipment. Install forty instruments and use modern monitoring systems to monitor and dominate the entire process of soil quality to ensure excellent water.
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What are the advantages of a submersible sewage pump?
1. The submersible sewage pump has compact structure, small volume, convenient movement and easy installation. It does not need to build a sewage pumping station, and it can work by diving into the water, greatly reducing the project cost.
2. The submersible sewage pump adopts double lower water absorption structure with low water absorption position. Because of the double suction type double flow channel single volute structure, the motor has no axial pulling force, which reduces and balances the light direction force and greatly improves the service life of the sewage pump. Times, the use efficiency is increased by 15%.
3.The use of large flow channel anti-blocking parts design, greatly improve the ability of dirt to pass, can effectively pass shorter fiber material and smaller diameter solid particles.
4. The sewage pump equipped with the external circulating water device can work continuously for a long time in the low water level. The large-flow submersible sewage pump with self-stirring impeller has an automatic mixing function, which can stir the water in the pool to make the sewage and dirt mix and discharge with the sewage pump.
5. The submersible sewage pump float switch can automatically control the stoppage of the sewage pump according to the required water level change, without special care.
6. The submersible sewage pump can be equipped with automatic safety protection control cabinet according to the user’s needs to monitor the leakage, leakage, overload and over-temperature of the large-flow submersible sewage pump to ensure reliable and safe operation of the sewage pump.
7. The double-rail automatic coupling safety system brings great convenience to the installation and maintenance of the large-flow submersible sewage pump. People do not have to enter and exit the sump for this purpose.
8. The characteristic is that there is a water leakage probe in the oil chamber. When the mechanical seal on the sewage pump side is damaged, the water enters the oil chamber, and the probe sends a signal to protect the sewage pump.
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Basic application and structure of submersible axial flow pump and mixed flow pump
ZQB series submersible axial-flow pump and HQB series submersible mixed flow pump are widely used in Agriculture, Industry and Civil engineering for drainage and water-supply, etc.. These pumps are features for low cost, easy installation, high reliability and can be automatically controlled.
Operation conditions:
1. Maximum medium temperature 50℃
2. PH 5~9
3. For pumping clear water or liquid physical character similar to water or liquid with little solids.
4. The pump can be stared 6-times each hour at the most with equal interval time.
5. Maximum submerged depth is 10 meters.
DESCRIPTION OF CONSTRUCTION
The main feature of pumps are that two kids of seals are used that are effective and reliable moving & static seals. Static seals is suitable foe use in all mating faces of static parts. The mating faces of static parts is equipped with “O” oil-proof rubber sealing ring. The auxiliary sealing material is non-dried sealing glue. Cable is separately, water pressure-tight encapsulated connection with strain relief, anti-kink protection and single lead sealing. Three mechanical seals are used in series between shaft and casing. Two of them are placed in oil chamber, one is used for protecting the motor from liquid leakage, the other for protecting the oil chamber from water. The oil chamber acts as buffer for leakage between the motor and pump, meanwhile mechanical seals and roller bearing are lubricated in it.
The pump insulation is class “F”=155℃
Rotor is aluminum cased squirrel-cage and shaft is stainless steel and has been dynamically balanced
.
At the top of the pump, there is a screw hole which is used for air leakage test before ex-work that each pump has been carried foe a gas leakage test with air pressure 0.15MPa for 5 min..
The rotating part is borne by four bearing. Upper bearing is an centripetal ball bearing, middle bearing is a short cylindrical bearing with a separable internal ring, these bearings with stand radial load. A rubber bearing act as auxiliary role for withstanding radial load. A big size centripetal thrusting roller bearing are used in the pump in order to bear weight of all rotating parts which bearing has low temperature and middle bearings are lubricated by No.3 lithium lubricating grease. All bearing are SKF brand.
Rotating direction of the motors shall be anti-clock wise rotation from the view of shaft according to the requirement of pump.
All pumps are equipped with thermal sensors for monitoring temp. rise of the winding. By lower thrusting bearing, a special sensor is located in oil chamber to monitor temp. rise of thrusting bearing, a device with double electrodes is set at the bottom of inside chamber of motor, if water is leaking into chamber, and reaches a certain high level from the bottom of chamber, the value of the resistance will be varied which will be changed into a switching signal by a water lever relay built in a control device. A electrode stretched out of the lower cover is used to check leakage in oil chamber of pump, and signal is transmitted by a water-level relay in the control device.
The pump has two main power cables and one control cable. Two main cable should be connected in parallel according to the same mark.(U,V,W,) Some pump (power below 90kW without any special requirements) only has one main power cable. See sketch of connection of power cable.
Pump impeller is semi-adjustable. Impeller blades can be adjusted according to the requirement of work by means of unscrewing nuts on the blades, pulling up fixing pin, moving the blades and adjusted the basic line of blade to a required angle line on the hub, then inserting the fixing pin fastening the nuts. Because inner surface of shell of impeller is cylinder, diameter of impeller must be machined after angle of blade is changed (small than that specified in contract). All vanes of delivered pump have been adjusted to the required angle specified in a contract. Users can adjust the vane by themselves, but it shall be paid a green attention to whether over power or over current.
Oil chamber is filled with No.20 machine oil. The volume of stored oil is determined by seeing oil overflowed through hole. For oil chamber, there are two hole separately located by two sides, one is injecting oil, the other is air vent hole. When injecting oil into the chamber, two holes shall be opened. After injecting oil, two holes shall be screwed up with two spigots. It shall be paid great attention to check whether the square seals have been broken.
A rubber bearing is equipped just up the hub of the impeller and is lubricated by water. It offers the impeller more stability and acts as a role of auxiliary bearing.
PREPARATION FOR OPERATING
The structure must be handed over ready for installation and must be dry and clean. In particular the inlet chamber must be empty and dry.
“As built” drawings of the civil work must be available by the client/consulting engineers in good time before starting installation.
Before installation, checking the record of main parts dimensions according to drawing to ensure that they can be connected smoothly. Inspecting and cleaning flange connecting surfaces.
For no load running on the ground, running time must be less than 15 seconds.
Checking the insulation resistance of the stator’s winding with a ohm meter of 500MΩ class, and never allow lower than 0.5 MΩ. The protective devices also need to be checked with a universal meter in 1K Ω position according to the requirement.
A trash screen shall be put in front of inlet channel.
Checking the frequency and voltage of power, whether it is meeting with the value specified in nameplate, the deviation of frequency is 1%, voltage deviation is±5%.
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Failure analysis and maintenance of submersible pumps
| Analysis of cause | Method of treatment |
| 1) reverse rotation of pump | 1) cut off over all power supply of control case, change over any two phase conductors of power cable |
| 2) pumping head is to high | 2) check a. the type of pump is correct or not b. the size of riser pipe is correct or not |
| 3) the pumped medium passes by pass | 3) check that valves are shut or not, then test the pump at full load. |
| 4) leak of discharge pipe | 4) find leak point and repair it |
| 5) discharge pipe may be clogged with oxide deposits | 5) check pipeling, clean and replace it |
| 6) pump is locally clogged | 6) raise up and clean it, if it is put in straining net, checking cleaning will be required as well |
| 7) impeller bottom plate wear out | 7) raise up it, adjust or renew the bottom plate. |
1.No flow rate after operation
| Analysis of cause | Method of treatment |
| 1) air clogging | 1) a. open and shut valves continually several times b. start/stop the pump some times, interval of starts is 2~3 minutes. |
| 2) checking this charge valve | 2) according to different installations |
| 3) reverse rotation of pump | 3) refer to 1.1 |
2.Frequency of start and stop of the pump is too high
| Analysis of cause | Method of treatment |
| 1) preset time of float switch is too short | 1) adjust the float switch, prolong operating time. |
| 2) non-return valve is fault liquid reversely flows into sewage sump | 2) check and maintain it |
3.Stopping is fault
| Analysis of cause | Method of treatment |
| 1) stop function. Of float switch is fault | 1) check and replace it if required |
| 2)float ball is caught at “operating” position | 2) loose off it and change its position if necessary |
4.Pump can not be started, fuse melts or circuit breaker trips
| Analysis of cause | Method of treatment |
| 1) relay in fault | 1) send to service department for repairing |
| 2) float is fault | 2) check that the by pass float switch can start the pump or not, if it can, float switch must be checked |
| 3) winding, connector or cable breaks off | 3) check with ohmmeter, if break off is turn, check winding, connector and cable |
| 4) pump is clogged | 4) cut off power supply, remove the pump out of sewage pump, clean clogging materials, test before resetting |
| 5) interlock of water leak or electric leakage | 5) red neon shows electric leakage interlock, yellow neon shows water leak interlock, maintain them before putting into operation. |
5.Circuit breaker/overload protector trips after pump starting
| Analysis of cause | Method of treatment |
| 1) voltage is low | 1) a. check the voltage of control case, if the voltage, is too low, the pump can not be used temporarily b. if cable is too long, cause excessive voltage drop, shorten the cable as possible and select properly large size cable |
| 2) voltage is too high | 2) add a transformer, adjust the voltage into the rated area |
| 3) the connection of pump is wrong | 3) check the cable colored No. and the connectors’ label in control case, check the connection. |
| 4) short circuit | 4) if red neon lights for a long time, do repair before operation |
| 5) control box or capacitor is fault | 5) a. check the control box carefully, don’t replace the circuit breaker with new element whose data is larger than recommended value. |
| 6) sludge or other deposits is piled at the area of shell’s bottom plate | 6) clean the pump and sewage sump, referring to related parts in “Notes for transportation” |
6.Pump can not started, but fuse does not melt and overload protector does not trip
| Analysis of cause | Method of treatment |
| 1) no electricity | 1) a. check that the control box is electrified or not b. check carefully that the control box is fault or not |
| 2) break – off of winding, cable connecting terminals or control box | 2) check cable and motor’s connecting terminals and winding |
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Maintenance knowledge of Centrifugal pump
First, before installation
1.We’d better coated with a suitable rust inhibitor on the centrifugal pump surface which has not been installed and used to prevent the pump is oxidized ;
2. Bearing maintenance of its oil lubrication, we’d better be filled with a suitable fluid. However, these oil selection also has a lot of skill. For example: During use, preferably filled with a grease, rather than going to use those mixed grease. Because the life of the mechanical mixing grease has a great harm.
Second, hold down
During the centrifugal pump use, such as for special reasons (annual leave) to suspend production, resulting in long-term hold pump, then we should note in the storage process:
1. The media in the pump should be rinse with water to ensure that no residue cavity, prevent deterioration and other causes liquid mixed fluid medium;
2. The centrifugal pump must be stored in those clean environments, and extremely dry place, otherwise, it is prone to rust liquid, liquid injection and corrosion inside the pump casing structure.
Special note: If not stored properly, may cause permanent and irreparable harm, so that will has a great impact on our future use.
In actual use, there may be more questions, if you want to learn more about the centrifugal knowledge, welcome to call for free advice, with your support we can do better.
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Effectively improve the performance of sewage pumps
1.Installed valve at the end of suction pipe of Self-suction sewage pump .
Suction bottom valve is actually a kind of check valve, which ensures that water can only enter the suction pipe from the pool and can not be back, so if the suction pipe filled with water, although the water pump axis elevation above the pool water level, but due to suction bottom The role of the valve, the suction pipe will not flow into the pool of water, so that the suction pipe has been filled with water to ensure that the pump can automatically and quickly start. The reliability of this method of water absorption by the impact of the quality of the end of the valve, for example, closed lax, water leakage, the water will slowly sink into the pool, a long time, there is no water suction pipe, causing the pump starts still Need artificial irrigation.
2.Self-suction sewage pump to reduce the inlet pipe bend, drop height and horizontal distance.
3.Self-priming pump set suction pump before the pump.
This approach requires a suction pipe on the pump suction pipe, the first run before the tank, the tank should be filled with artificial water, the first stop, because the intake pipe suction tube height above the surface height of
the pipe, despite the The water level inside the tank is lower than the height of the water surface of the tank, the water inside the tank will not turn back into the pool, so the water canister can store a certain water, and because of the height of the water pipe Below the tube surface height, it can ensure that the pump suction tube filled with water, after the pump and then run, the water tank was pumped away, negative pressure tank, the pool of water under the effect of atmospheric pressure added to the Suction tank inside, through the sink tank inside.
4.Self-suction sewage pump in the pump suction pipe set vacuum pump, pump start, the vacuum pump first start, so that the pump suction tube filled with water first, to ensure that the pump automatically and quickly start. This method of water needs to have a sound automatic control system to ensure the normal work.
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How to improve the anti – cavitation performance of centrifugal pump
(1)Improve the centrifugal pump suction port to the impeller near the structural design. Increase the flow area; increase the radius of curvature of the inlet section of the impeller cover, reduce the rapid acceleration and decrease of the liquid flow; reduce the thickness of the inlet of the blade, and make the leaf inlet rounded so that it is close to the streamline, Reduce the speed of the blade around the blade and increase the surface of the impeller and the blade surface to reduce the loss of resistance;
(2)Use pre-induction wheel, so that the flow in the pre-induction wheel in advance to work to improve the flow pressure.
(3)Use double suction impeller, so that the flow from the impeller on both sides of the same time into the impeller, the import cross-section doubled, the import flow rate can be reduced by double.
(4)The design of the use of slightly larger positive angle to increase the blade inlet angle, reduce the blade at the entrance of the bend, reduce the blade blockage to increase the import area; improve the working conditions under high flow to reduce Flow loss. But the angle should not be too large, otherwise the impact of efficiency.
(5)Use anti-cavitation materials. Practice shows that the higher the strength, hardness and toughness of the material, the better the chemical stability and the stronger the resistance to cavitation.
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Fast and easy assembly of multi-stage centrifugal pump
Multistage centrifugal pumps should be placed as far as possible in a well ventilated place to facilitate rapid cooling and reduce motor temperature. Otherwise, run for a long time, easy to burn the motor.
If the use of multi-stage centrifugal pump, because did not remove the plastic film covered in the motor, causing the motor overheating, burn the coil. In addition, before starting, be sure to check the water inside the pump, otherwise, not only affect the self-priming performance, and easy to burn the shaft seal parts. Under normal circumstances, multi-stage centrifugal pump starts after 3 to 5 minutes that should be out of water, or should immediately stop inspection.
When the multi-stage centrifugal pump once a failure, avoid their own hands. Because of their own demolition, I do not know where the fault caused by blindly split a pass; Second, no special tools and often damage the original good parts. The best way is to have experienced, large-scale maintenance point repair, and timely replacement of “overage” parts and some wearing parts. Under normal circumstances, multi-stage centrifugal pump should be repaired once every six months, put an end to “sick” work.
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The reasons of no flow of multi-stage centrifugal pump
First,multi-stage centrifugal pump outlet pipe resistance is too large; pump direction of rotation; multi-stage pump impeller flow blockage or damage, pump speed is insufficient.
Second, check or shorten the horizontal multi-stage pump outlet pipe to eliminate dirt or replace the impeller impeller; check the pump motor, increase the pump speed.
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