electric butterfly butterfly board installed in the direction of the pipe diameter. Electric Butterfly Valves in the cylindrical channel, disc-shaped butterfly plate around the axis of rotation, rotation angle of 0
1 preparation before the start
open to ensure the safe operation of centrifugal pump plant, should be done before starting the necessary checks. First hand the slow turn coupling or pulley, water pump rotation is correct in observing, rotation is flexible, stable, and whether the debris in the pump, the bearing is functioning properly, the belt tension is appropriate; check that all screws are strong; check whether the unit around impede the operation of the debris; Check suction pipe submergence depth is adequate; have to turn off the water valve to reduce the starting load, and timely attention starts to open the valve.
2 running check
boot, you should check all instruments are working properly, stable, and should not exceed the current rating. Pressure gauge should be in the design range; check out the open centrifugal water pump plant is normal, check all parts of the unit for leaks; check compaction of fill, usually a small amount of filler at the appropriate leakage (less than 10 per minute ~ 20 drops), the mechanical seal leakage should not be greater than 10mL / h (about 3 drops per minute); rolling temperature should not exceed 75 ℃; bearing temperature should not exceed 70 ℃ and watch for abnormal noise, abnormal vibration, note that the reduction of water; to adjust the depth of the inlet port submerged; always clean up floating debris on the trash racks; through the belt drive, but also the belt is slipping
3 down and stop after the note
stop off the water valve and then preceded down, to prevent backflow of water, damage to parts; each stop, they should promptly wipe the oil pump and piping to keep the unit clean appearance, to discover hidden; after the winter shutdown, the water should be immediately put the net, to prevent cracking the pump and internal parts; in use after the end of the season, to carry out necessary maintenance
4 centrifugal periodic inspection
ISGD, IRGD low-speed vertical pipe of the pump cycle checkpoint can be divided into the following three types: routine inspections, the use of checks, as described above; monthly check, without removing the case of parts, equipment exterior cleaning and minor repairs, including the temperature of the bearing, shaft seal and cause leakage of electrical insulation and other aspects of the inspection; regular maintenance, including replacement of seal oil, check the pump and motor shaft for wear in the checks, check coupling rubber ring damage control, cleaning mechanical seal, coolant filter and pump filter, check the wear of sliding parts, check parts contact with liquid damage, corrosion, etc.
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hydraulic efficiency of the system depends on the volumetric efficiency of hydraulic pumps, when the volumetric efficiency dropped to 72%, you need routine maintenance, replacement of bearings and seals of aging, to replace or repair the gap exceeds the friction with the deputy, its performance is restored.
1, the hydraulic pump: direct axis is divided into pressure piston pump swash plate type oil from oil-type two. Most oil-based hydraulic pressure using a pressure tank, but also the oil pump itself up with the wheel cylinder to the pump inlet pressure provides oil. Since the oil-type oil pump’s self-competence, without external supply. Pressure hydraulic oil tank, after each time you start the machine, must wait to use hydraulic pressure tank after the stains, to operate machinery. Such as lack of hydraulic pressure when the tank as the machine, the pump will cause whip pull off and slip phenomenon, the board will cause the pump body and the platen of the non-return to normal wear and tear. The piston pump oil used up, the use of 3000h, the operator checks the daily needs of the piston pump 1-2 times to check the sound is normal pump operation. Found to slow down or bored cylinder car, you should check for the disintegration of the charge pump, check whether there is scratch the impeller edge phenomenon, internal gear pump gap is too large.
2, for the self-suction type piston pump, the hydraulic oil tank shall not be less than the oil within the standard limit, to maintain a sufficient number of hydraulic oil. The higher the hydraulic oil cleanliness, longer pump life.
3, piston pump bearings is the most important parts of the bearing, the bearing clearance there is no guarantee that within three pairs of hydraulic friction pairs normal space, but also undermine the friction pair of hydrostatic bearing film thickness, reducing piston pump bearing life. According to information provided by pump manufacturer, the average bearing life of 10000h, this value needs to be replaced over the new port. Dismantled bearings, no professional testing equipment can not detect the bearing clearance, but to use visual, such as surface scratches found roller or discoloration, it must be replaced. When replacing the bearings, the bearings should be noted that the original letters and type, piston pumps were powered by large load bearing capacity of the bearing, it is best to buy the original manufacturer, the original specifications of the product, if the replacement of another brand, you should consult an experienced bearing look-up table for the exchange of personnel, the purpose is to maintain the accuracy of grade and load bearing capacity.
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4, three pairs of friction deputy inspection and repair: pistons and piston cylinder hole according to the standard replacement parts, when parts of a variety of ultra-poor gap, the method of repair according to the following:
(1) cylinder sleeve insert mounted copper, copper can be used to replace the sets of methods to repair. First, a group of plunger rod diameter trimmed to uniform size, then more than 1000 # sandpaper polishing diameter. Copper cylinder sleeve installed three methods: (a) or copper cylinder sleeve installed plus hot extrusion temperature refrigeration, assembly interference; (b) adopt a Loctite glue the assembly, which we approach requires copper jacket diameter surface grooves; (c) cylinder hole tapping, thread processing copper sleeve outer diameter, coated with Loctite glue, screw assembly.
(2) melting and burning copper binding mode of the cylinder sleeve, repair as follows: (a) the use of ground rods, repair manual or mechanical grinding cylinder bore; (b) the use of coordinate boring machine, re-boring the cylinder hole ; (c) the use of reamers repair cylinder bore.
(3) the use of “surface engineering”, as follows: (a) plating technique: a layer of hard chrome plated piston; (b) brush plating techniques: the surface plating wear on plunger materials; (c) thermal spray or electric arc spraying or spray: spray high-carbon martensitic wear-resistant materials; (d) laser cladding: the plunger surface, high hardness wear-resistant cladding alloy powder.
(4) sets of cylinder bore no copper materials are mostly nodular cast iron cylinder block, cylinder wall on the preparation of amorphous films or coatings. Because the cylinder bore wall with this particular material, so in order to form a hard – hard matching friction deputy. If the blind cylinder bore polishing, the surface of the cylinder bore wall material research out of this layer, the structural properties of friction more will change. Vice-friction coating to be removed, if the force used, the friction surface temperature will rise rapidly, the plunger rod and cylinder Kong Fasheng glue
5, the other plunger rod surface preparation in a unique film with a coating containing lubricating antifriction + Wear + functions, this group vice actual friction or hard – soft pair, people change once the coating, will destroy the best match of friction pair materials, repair of these special piston pump, it is necessary to a professional repair shop.
hydraulic efficiency of the system depends on the volumetric efficiency of hydraulic pumps, when the volumetric efficiency dropped to 72%, you need routine maintenance, replacement of bearings and seals of aging, to replace or repair the gap exceeds the friction with the deputy, its performance is restored.
1, the hydraulic pump: direct axis is divided into pressure piston pump swash plate type oil from oil-type two. Most oil-based hydraulic pressure using a pressure tank, but also the oil pump itself up with the wheel cylinder to the pump inlet pressure provides oil. Since the oil-type oil pump’s self-competence, without external supply. Pressure hydraulic oil tank, after each time you start the machine, must wait to use hydraulic pressure tank after the stains, to operate machinery. Such as lack of hydraulic pressure when the tank as the machine, the pump will cause whip pull off and slip phenomenon, the board will cause the pump body and the platen of the non-return to normal wear and tear. The piston pump oil used up, the use of 3000h, the operator checks the daily needs of the piston pump 1-2 times to check the sound is normal pump operation. Found to slow down or bored cylinder car, you should check for the disintegration of the charge pump, check whether there is scratch the impeller edge phenomenon, internal gear pump gap is too large.
2, for the self-suction type piston pump, the hydraulic oil tank shall not be less than the oil within the standard limit, to maintain a sufficient number of hydraulic oil. The higher the hydraulic oil cleanliness, longer pump life.
3, piston pump bearings is the most important parts of the bearing, the bearing clearance there is no guarantee that within three pairs of hydraulic friction pairs normal space, but also undermine the friction pair of hydrostatic bearing film thickness, reducing piston pump bearing life. According to information provided by pump manufacturer, the average bearing life of 10000h, this value needs to be replaced over the new port. Dismantled bearings, no professional testing equipment can not detect the bearing clearance, but to use visual, such as surface scratches found roller or discoloration, it must be replaced. When replacing the bearings, the bearings should be noted that the original letters and type, piston pumps were powered by large load bearing capacity of the bearing, it is best to buy the original manufacturer, the original specifications of the product, if the replacement of another brand, you should consult an experienced bearing look-up table for the exchange of personnel, the purpose is to maintain the accuracy of grade and load bearing capacity.
4, three pairs of friction deputy inspection and repair: pistons and piston cylinder hole according to the standard replacement parts, when parts of a variety of ultra-poor gap, the method of repair according to the following:
(1) cylinder sleeve insert mounted copper, copper can be used to replace the sets of methods to repair. First, a group of plunger rod diameter trimmed to uniform size, then more than 1000 # sandpaper polishing diameter. Copper cylinder sleeve installed three methods: (a) or copper cylinder sleeve installed plus hot extrusion temperature refrigeration, assembly interference; (b) adopt a Loctite glue the assembly, which we approach requires copper jacket diameter surface grooves; (c) cylinder hole tapping, thread processing copper sleeve outer diameter, coated with Loctite glue, screw assembly.
(2) melting and burning copper binding mode of the cylinder sleeve, repair as follows: (a) the use of ground rods, repair manual or mechanical grinding cylinder bore; (b) the use of coordinate boring machine, re-boring the cylinder hole ; (c) the use of reamers repair cylinder bore.
(3) the use of “surface engineering”, as follows: (a) plating technique: a layer of hard chrome plated piston; (b) brush plating techniques: the surface plating wear on plunger materials; (c) thermal spray or electric arc spraying or spray: spray high-carbon martensitic wear-resistant materials; (d) laser cladding: the plunger surface, high hardness wear-resistant cladding alloy powder.
(4) sets of cylinder bore no copper materials are mostly nodular cast iron cylinder block, cylinder wall on the preparation of amorphous films or coatings. Because the cylinder bore wall with this particular material, so in order to form a hard – hard matching friction deputy. If the blind cylinder bore polishing, the surface of the cylinder bore wall material research out of this layer, the structural properties of friction more will change. Vice-friction coating to be removed, if the force used, the friction surface temperature will rise rapidly, the plunger rod and cylinder Kong Fasheng glue
5, the other plunger rod surface preparation in a unique film with a coating containing lubricating antifriction + Wear + functions, this group vice actual friction or hard – soft pair, people change once the coating, will destroy the best match of friction pair materials, repair of these special piston pump, it is necessary to a professional repair shop.
manufacturing process compared with other institutions, the valve manufacturing process has the following characteristics:
① valve rough manufacturing process and inspection process more complicated.
valves rough castings are thin-walled shell structure called the complex pieces. Casting requirements of its smooth surface, cast the word clear, especially to have dense defects. To meet these requirements, casting a series of technological measures should be taken, such as the use of high refractoriness of the material and shape of sand moisture control, modeling the real fight should be to ensure the sand layer hardness, using reasonable pouring cap system and strict control of the mouth casting speed and temperature. As the technical requirements for high valve casting process than the general rough cast complex.
In addition, blank except check valve size, location accuracy and appearance, and some have as microstructure, mechanical properties, corrosion resistance and non-destructive testing and other tests, so the valve inspection process is more complex .
② valve installed on the machine parts more difficult
valve main parts of the structure, the shape is more complex, some parts are thin-walled, slender pieces, poor rigidity. In the machine tool, the positioning and clamping are more difficult, so complex and often require a special fixture.
some valve parts, the lower the accuracy of positioning the base surface, high surface roughness, and sometimes even non-machined surface orientation. The sealing surface to be machined parts such as accuracy and surface roughness requirements are high, it was difficult to ensure processing quality. Therefore, in order to meet the technology needs, the base surface is often required to improve the positioning accuracy and reduce the surface roughness, or in the non-machined surface orientation on the processing of the base surface, which increases the complexity of the valve manufacturing process.
③ machining difficult
the valve with a broad range of materials, in addition to a variety of cast iron, carbon steel, but most of its high strength, corrosion resistance and high hard cutting materials are very poor, difficult to achieve the required precision parts and surface roughness. The geometry of the valve sealing surface shape accuracy and surface roughness are very demanding and therefore more difficult to increase the valve machining. At the same time, cutting the valve material difference, and gave the valve processing methods, tool material, cutting, process equipment, so bring a lot of new problems.
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traditional port control valve out of the oil through a valve to be, to listen to two ports in the valve opening corresponding to the relationship as early as the design process to determine when, in the course can not be modified, so that the oil through two the mouth of the flow or pressure can not be controlled independently of each other.
1, the traditional single-spool valve defects
conventional single spool valve hydraulic system consisting of a reasonable solution of the following features is difficult and the contradiction between the control:
(1) hydraulic system designed to improve system stability and reduce the impact of load changes on the speed, or sacrifice some of the functions we want to achieve, or additional hydraulic components, such as control valves, pressure control valve, by increasing the damping, stiffness to improve system speed improve system stability. However, this component will reduce the increase in efficiency, waste of energy; also makes the whole system can be * reduced, increasing costs.
(2) As for the special structure allows the user to achieve a particular function must purchase the corresponding hydraulic components, coupled with construction machinery manufacturers will be based on different end-user requirements to design the corresponding function, this will cause procurement of similar manufacturers, multi-standard hydraulic control components to meet the needs of the different functional requirements, the product is not conducive to universal and product management, will also greatly enhance the product cost.
(3) As the executive body and out of hydraulic fluid through a valve to control both sides of the pressure control actuator alone is impossible. Therefore, the oil pressure acting on the dorsal movement of the actuator opposite direction, with the dorsal oil pressure, the executing agency for the shelf-life movement, into the oil side of the pressure must be increased. This will make the function of the hydraulic system increases consumption, low efficiency, heat increases.
dual-spool hydraulic system technology, as the executing agency out of the oil side of the spool valve port location and control separate, independently of each other, so that by two different combinations of spool control, the use of software programming can be very good solution to the traditional single-valve system can not solve the problem, but also can be easily achieved in conventional hydraulic systems difficult to accomplish.
2, two-spool valve are two basic control strategies
due to two dual-port valve for control flexibility, the two ports can be taken separately flow control, pressure control or flow pressure control. Positive introduce two simple control strategy.
(1) load direction remains unchanged throughout the course of their work
We know, for cranes, excavators, loaders and other terms of the hydraulic cylinder in the direction of the whole course of their work load is always maintained. Following the example of the hydraulic cylinder luffing crane to explore the dual spool control strategies.
cylinder luffing crane in the course of its work force, the load remains the same direction, so we can take control of the hydraulic cylinder rod with a pressure control chamber with no flow control rod control strategy.
rodless cavity flow control is not connected to the rod by detecting the side of the valve chamber on both sides of pressure before and after, according to the required amount of flow into or out of, to calculate the size of valve opening; rod chamber side with pressure control , so that the side to maintain a low pressure, making more energy efficient.
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Since we use a non-pole cavity flow control, so the original control system available balance valve used in a pilot-operated check valve instead. This will eliminate system instability caused by balancing valve, thereby enhancing the system stability.
(2) load direction of the change in the course of their work
In this case, to take “into the oil side of the pressure control, the oil side of the flow control” in the hydraulic cylinder rod chamber side with pressure control, there is no flow control rod side chamber.
same direction as the load, due to the oil side of the flow control, we can two-way balancing valve with check valve to replace, thereby enhancing the stability of the system. Into the oil side with a pressure controller to maintain a lower reference pressure, on the one hand to improve system efficiency, the other hand, the system does not occur cavitation.
To make changes in the load direction
body of work can be well controlled, the other a PI controller will be applied to the rod chamber of the pressure controller, when the load direction changes, no rod chamber pressure will be reduced; If the rod will still maintain a low pressure chamber, when the load is large, the hydraulic cylinder will reverse direction. At this point we can use to monitor the increase in PI controller rodless chamber pressure changes, when the PI controller detects that the lever cavity pressure is lower than the reference value, will increase rod chamber pressure controller set pressure, thus ensuring the system works.
valve the most obvious and one is not a question of comfort noise. For humans, noise can interfere with not only life, but also lead to permanent hearing failure and unsafe working environment. Studies have shown that long-term exposure to high noise levels, people’s hearing will be damaged. Hearing damage is progressive and irreversible, beginning with the high frequency failure, the top continues to fail the final hearing will result in a lower frequency of failure, which affects the ability to listen to normal language. When subjected to low frequency noise, the function of human organs such as heart or liver, may also be affected. In addition, noise and vibration will affect the associated performance and lead to valve pipe valve and adjacent equipment fatigue.
Essentially, when the vibration is generated in a wide range of atmospheric pressure changes, it will generate noise, and then as the noise transmitted to the eardrum. Eardrum to the speed of sound [which is 1100ft / s (335m / s) or 750m / h (1200km / h)] spread. Valve noise can be generated in many different ways, but the most common cause of valve geometry is generated by the turbulence caused by the spread of the downstream pipeline. In many cases, the noise could not help spread the valve body itself, because the body itself is rigid and sturdy.
process turbulence will produce the vibration of the valve or valve components. Noise from the valve assembly within the random vibration generated by pressure fluctuations caused by collisions or by the fluid logistics obstacles, such as spool and disk or other closure components caused by the vibration. When the closure element continue to impact its director, the long time will lead to an explosion of noise. Because its frequency is lower than 1500Hz, it does not interfere with normal observers. However, these stem or with a guide shaft can damage the explosion limits of orientation and the seat surface. Valve parts explosion noise of another deputy secondary benefit is that the noise generated within the turbulent pressure valve to provide a warning message, so corrected before the accident is required. Vibration can also be certain in its natural resonance frequency of the valve parts, or cause, they are often at a lower noise level (less than 100dBA) found. This type of noise is characterized by a single tone or sound Weng Weng (frequency 300 ~ 700Hz), which produce high levels of stress in the material, leaving the component materials caused by material fatigue and weak. Noise but also by hydrodynamic or aerodynamic sound caused by the fluid. For liquid handling, fluid power noise by flow, cavitation and turbulence caused by flash, or when the fluid produced by the contraction of cross-section caused by speed. In short, the logistics of liquid produced by the noise does not produce a high noise level and for staff to endure. In severe cavitation or flashing operation, noise levels can reach a higher level must be changed within the installation process or in the anti-cavitation valve components for disposal.
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valve routine maintenance
1, the valve should be kept dry and ventilated room, access to be blocked at both ends.
2, long-term storage of the valve should be checked regularly to remove dirt, rust and oil-coated surface in the process.
3, after installation, should be regularly checked, the main inspection items:
(1) sealing surface wear.
(2) trapezoidal stem and stem nut thread wear.
(3) packing is outdated, should be replaced if damaged.
(4) repair the valve assembly, sealing performance test should be carried out.
valve greasing maintenance work
before soldering operation of the valve before and after the commissioning of professional conservation work for the service valve manufacturing operations play a vital role in the correct and orderly and effective maintenance will protect the valve, the valve normal valve function and prolong life. Valve conservation appears to be simple, it is not. Work is often overlooked aspect.
First, valve grease, it is often overlooked issue of the amount of grease. Grease gun, after refueling, the operator selects the valve and connected after the manner of grease, the grease job. There are two cases: on the one hand greasing less grease less sealing surface is accelerated wear due to lack of lubricant. The other hand, excessive grease, resulting in waste. Is no basis for the type of valve type, valve sealing capacity of different accurate calculations. Can be calculated valve size and type of sealing capacity, and then injected into a reasonable amount of grease.
Second, the valve grease, often ignored problem of stress. In the greasing operation, the grease pressure peak was regularly changed. Pressure is too low, seal leakage or failure, the pressure is too high, greasing port plug, sealing ring and the inner lipid hardening or valve ball, valve plate locking. Usually the grease pressure is too low, the injection of grease into the valve chamber more than the bottom, generally occurs in the small gate. The grease pressure is too high, while checking the grease nozzle, in the case identified the grease hole blocking situation to be replaced; the other hand, lipid-hardening, to use the cleaning fluid, repeated failure to soften the sealing resin, and grease into the new replacement . In addition, the seal type and seal materials also affect the grease pressure, different forms have different sealing grease injection pressure, in general, seal the grease pressure is higher than the soft seal.
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Third, the valve greasing, pay attention to the valve problem in the switch position. Valve maintenance are generally in the open position when the state of maintenance of special circumstances, choose to close. Other valves can not be any open spaces punished. Valve must be in conservation when turned off, to ensure full of grease seal ring groove along, if the open position, sealing resin flow channel or directly fall into the valve chamber, resulting in waste.
Fourth, the valve greasing, the grease effect is often ignored problem. Operation pressure grease, grease, switching position are normal. However, to ensure that the valve greasing effect, and sometimes need to open or close the valve, on lubrication check to make sure the ball valve or gate valve surface lubrication evenly.
fifth, greasing, pay attention to the pressure relief valve and blanking plug with sewage problems. Pressure test the valve, seal chamber and the valve chamber gas temperature and moisture boost for the environment, greasing to conduct sewage pressure relief, in order to facilitate the smooth progress of the work greasing. After greasing the seal cavity is full replacement of air and moisture out. Time to vent out the valve cavity pressure, but also to protect the use of safety valves. After greasing, be sure to tighten the wire blocking drainage and pressure relief to prevent accidents.
Sixth, greasing, the grease evenly to pay attention to the problem. Normal greasing, the grease from the grease out of the hole nearest the mouth, first-out fat, and then to the low end is the high point, successive out fat. If you do not follow the law or no fat, prove the existence of congestion, timely and clear communication process.
seventh, greasing also observed diameter valve seat ring flush with the problem. For example, ball valve, open spaces if there is interference, can be adjusted to the open position limit switch inside, confirm and lock straight path. Adjustment limit is not only the pursuit of a party on or off position, to the overall consideration. If the open position flush off place, will cause the valve off lax. Similarly, adjusting the relations in place, we must consider the open position accordingly. Ensure that the right-angle valve travel.
eighth, grease, the grease will seal the mouth. Avoid impurities into, or greasing the mouth lipid oxidation, capping to apply anti-rust grease to avoid rust. Applications for the next operation.
ninth, greasing, but also consider the order in the next oil delivery in specific issues and problems. Given the quality of diesel and petrol, gasoline should be considered erosion and decomposition capability. Valve operation in the future, encountered gas segment operations, replenish grease to prevent wear and tear occurs.
Tenth, grease, do not ignore the stem part of the grease. Parts of a sliding sleeve valve shaft or packing, but also the need to maintain lubrication to reduce friction during operation, if not to ensure lubrication, the electrical torque increase when worn parts, manual operation switch effortlessly.
eleventh, some marked with an arrow on the valve body, if not with English FIOW writing, for the sealing seat role in the direction of the flow of information not as a medium, since the vent valve in the opposite direction. Typically, two-seater with two-way flow valve seal.
XII, valve maintenance, also pay attention to the first and the transmission of electric water problems. Infiltration of rainwater, especially during the rainy season. First, the transmission or drive shaft cover rust, and second, the winter freeze. Caused by electric valve operation torque is too large, no-load damage to transmission components or super torque motor would jump to protect electric operation can not be achieved. Damage to transmission parts, manual operation can not be. After the action in the ultra-torque protection, also can not switch to manual operation, such as the forced operation, the damage to the internal alloy components.
summary, valve maintenance, truly scientific attitude in order to make the valve maintenance work to achieve the desired effect and application purposes.
1, size limits
INA bearings can be installed
usually the space is restricted. In most cases, the shaft (or INA bearing diameter) is based on mechanical design or other design limitations. Therefore, INA Bearing type and size selection is based on the diameter of INA bearings and decide. Thus, the standard size of INA bearings of the main table are based on international standards prepared by diameter size.
2, speed
permissible speed is based on the type of INA bearings, size, precision, cage type, load, lubrication, and cooling method and other factors identified. Table lists the INA Bearing INA Bearing in standard precision oil lubrication and grease lubrication of the allowed speed. Typically, deep groove ball bearings INA, self-aligning ball bearings and cylindrical roller INA INA bearings are suitable for high speed applications.
3, INA Bearing tolerance
INA Bearing size precision and rotational accuracy is based on ISO and JIS standards. For applications requiring high precision and high speed machinery, recommended five or more precision INA bearings, deep groove ball INA bearings, angular contact ball bearings or cylindrical roller INA INA bearings are suitable for high precision mechanical operation. Rigidity, when the INA rolling bearings and roller contact surface pressure, will produce elastic deformation. Some machines need to minimize elastic deformation. Than ball bearings INA roller bearings produced by INA small elastic deformation.
4, installation and removal
some applications require frequent removal and installation, to ensure regular testing and maintenance. Can be installed inside and outside the ring, such as the INA bearings: cylindrical INA bearings, needle bearings INA, and INA bearings are tapered for this.
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valve’s primary role is used to quickly switch the fluid. Because the handle rotated ninety degrees to achieve the full effect of all relevant, it is also called “quick-opening.” Because the switch is not easy to accurately adjust the degree of control, so not suitable for flow regulation.
ball is a sphere with a circular channel to open and close parts, ball rotation to achieve with the stem of the valve opening and closing action. Valve open and close a hole in the piece is a sphere around the axis of rotation perpendicular to the channel, so as to achieve the purpose of opening and closing the channel. The main valve for opening and closing of media channels and equipment used.
valve main advantages are as follows:
for the regular operation, open and close quickly, lightweight.
1. fluid resistance.
2. structure is simple, relatively small size, light weight, ease of maintenance.
3. seal.
4. is not limited mounting direction, the flow of the medium can be any.
5. no vibration, noise.
The main drawback
valve as follows: valve structure can be classified according to: floating ball valve, fixed ball valve, ball valve and flexible seal valve; per channel can be divided into direct-to-type, angle-and three-way etc., can be divided into three-way T-shaped and L-shaped two. Work can be divided according to the connecting threaded connection, flange connection and welded three.
valve installation and maintenance should note the following:
1. to leave the position of the valve stem rotation
2. can not be used for throttling.
3. with vertical transmission of the valve should be installed.
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Although this noise is essentially a result from manufacturing errors, but in fact still with the choice of lubricant, bearing installation conditions, the accuracy of shaft and bearing on the state. This noise is further divided into cage sound of two types of sound and vibration pattern, as described below:
(1) sound and control cage
cage sound is intense vibration of the cage and rolling elements have been issued for the impact of periodic vibration and noise, the hole in the pocket loose and prone to large friction.
This noise occurs mainly in ball bearings and tapered roller bearings, and stamping cage and solid cage occurs, the use of grease or oil lubrication lubrication occurs, but in poor lubrication or lubricant dried up, the large radial clearance, the outer ring under a moment load, and poor cage structure and accuracy is not high, the more likely, the web or cage severe rivet head will suddenly break.
cage noise and vibration control methods are; good lubricant to use lubrication; reduce the bearing installation error; compressed radial bearing axial clearance or preload to be appropriate, and use well-structured with reasonable accuracy cage bearings, or switch to cage firmly and without the wear and tear of bearings.
(2) sound and vibration pattern control method
chatter sound is directly related to the bearing surface waviness on rolling noise, which is a pure tone noise, the constant speed, its frequency is also constant, and for changes in speed, it also will be the frequency of change.
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