2020年4月13日（月）
Operating Characteristics Of Hydraulic Pumps
The Hydraulic Pumps converts mechanical energy into hydraulic energy. When the hydraulic pump is running, it performs two functions. First, its mechanical action creates a vacuum at the pump inlet, causing atmospheric pressure to force liquid from the reservoir to the pump inlet line. Secondly, its mechanical action transports this liquid to the outlet of the pump and presses it into the hydraulic system.
The pump produces liquid movement or flow: it does not generate pressure. It generates pressure to produce the required flow rate, which is a function of the resistance to fluid flow in the system. For example, for a pump that is not connected to the system (load), the fluid pressure at the pump outlet is zero. In addition, for pumps delivered to the system, the pressure will only rise to the level needed to overcome the load resistance.
All pumps can be classified as positive displacement or non-positive displacement. Most pumps used in hydraulic systems are positive displacement pumps.
Non-positive displacement pumps produce continuous flow. However, since it does not provide a reliable internal seal to prevent slippage, its output will vary significantly with changes in pressure. Centrifugal pumps and propeller pumps are examples of non-positive displacement pumps.
If the output port of the non-positive displacement pump is blocked, the pressure will rise and the output will decrease to zero. Although the pumping element will continue to move, the flow will stop due to slippage inside the pump.
In positive displacement pumps, the slip is negligible compared to the volumetric output flow of the pump. If the output port is blocked, the pressure will immediately increase to the point where the pump element or its casing will fail (it may explode if the drive shaft does not break first) or the pump's prime mover will stall.
A positive displacement pump is a pump that discharges (delivers) the same amount of liquid in each rotation cycle of the pumping element. Due to the tight fit between the pumping element and the pump housing, it can be delivered constantly in every cycle. That is, the amount of liquid sliding through the pumping element in the positive displacement pump is minimal and negligible compared to the theoretically highest possible delivery. Regardless of the pressure changes during pump operation, the delivery volume per cycle remains almost constant. Please note that if the fluid slips severely, the pump is not working properly and should be repaired or replaced.
Positive displacement pumps can be fixed displacement or variable displacement. The output of the fixed displacement pump is kept constant at a given pump speed during each pumping cycle. The output of the variable displacement pump can be changed by changing the geometry of the displacement chamber.
Other names describing these pumps are hydrostatic pumps for positive displacement and hydrodynamic pumps for non-positive displacement. Hydrostatic pressure means that the pump converts mechanical energy into hydraulic energy with a smaller liquid volume and speed. In a hydrodynamic pump, the speed and movement of liquid are large; the output pressure actually depends on the speed at which the liquid flows.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of hydraulic pumps. Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Follow us to learn more about hydraulic pump product information and technical information: https://www.china-vanepump.com/
The pump produces liquid movement or flow: it does not generate pressure. It generates pressure to produce the required flow rate, which is a function of the resistance to fluid flow in the system. For example, for a pump that is not connected to the system (load), the fluid pressure at the pump outlet is zero. In addition, for pumps delivered to the system, the pressure will only rise to the level needed to overcome the load resistance.
All pumps can be classified as positive displacement or non-positive displacement. Most pumps used in hydraulic systems are positive displacement pumps.
Non-positive displacement pumps produce continuous flow. However, since it does not provide a reliable internal seal to prevent slippage, its output will vary significantly with changes in pressure. Centrifugal pumps and propeller pumps are examples of non-positive displacement pumps.
If the output port of the non-positive displacement pump is blocked, the pressure will rise and the output will decrease to zero. Although the pumping element will continue to move, the flow will stop due to slippage inside the pump.
In positive displacement pumps, the slip is negligible compared to the volumetric output flow of the pump. If the output port is blocked, the pressure will immediately increase to the point where the pump element or its casing will fail (it may explode if the drive shaft does not break first) or the pump's prime mover will stall.
A positive displacement pump is a pump that discharges (delivers) the same amount of liquid in each rotation cycle of the pumping element. Due to the tight fit between the pumping element and the pump housing, it can be delivered constantly in every cycle. That is, the amount of liquid sliding through the pumping element in the positive displacement pump is minimal and negligible compared to the theoretically highest possible delivery. Regardless of the pressure changes during pump operation, the delivery volume per cycle remains almost constant. Please note that if the fluid slips severely, the pump is not working properly and should be repaired or replaced.
Positive displacement pumps can be fixed displacement or variable displacement. The output of the fixed displacement pump is kept constant at a given pump speed during each pumping cycle. The output of the variable displacement pump can be changed by changing the geometry of the displacement chamber.
Other names describing these pumps are hydrostatic pumps for positive displacement and hydrodynamic pumps for non-positive displacement. Hydrostatic pressure means that the pump converts mechanical energy into hydraulic energy with a smaller liquid volume and speed. In a hydrodynamic pump, the speed and movement of liquid are large; the output pressure actually depends on the speed at which the liquid flows.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of hydraulic pumps. Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Follow us to learn more about hydraulic pump product information and technical information: https://www.china-vanepump.com/
2020年4月2日（木）
Vane Pumps Operating Condition Adjustment Method
The operating point of the Vane Pumps is determined by the intersection of the performance curve of the pump and the characteristic curve of the pumping device. When selecting and using the pump, the performance parameters of the operating point of the pump often deviate from the highest efficiency point, which does not meet the actual needs, causing Decreased work efficiency, severe overload or insufficient load of the power machine, too much or too little water from the pump, too high or too low lift, cavitation, etc. At this time, you must change the performance curve of the pump or the characteristic curve of the pumping device. Move the operating point to meet the requirements. This method is called adjusting the operating point of the pump. There are 5 commonly used adjustment methods: variable speed adjustment, reducing diameter adjustment, variable angle adjustment, variable adjustment adjustment and shunt adjustment.
I. Speed adjustment
Changing the speed of the pump can change the performance of the pump to achieve the purpose of adjusting the operating point of the pump. This method of adjustment is called variable speed adjustment.
There are two ways to change the speed of the pump, one is to use a variable speed power machine, and the other is to use a variable speed transmission equipment. The speed of the internal combustion engine can be automatically adjusted according to the load; the methods of variable speed of the motor mainly include frequency conversion, variable resistance, variable pressure, variable capacity adjustment, etc.
Second, reducer adjustment
Turning the outer diameter of the impeller of a centrifugal pump or a mixed flow pump can change the performance of the pump, thereby adjusting the operating point of the pump, and expanding the use of the pump. This adjustment method is called reducing adjustment, also called turning adjustment or cutting adjustment. Turning regulation has been widely used in pump manufacturing. In order to expand the use of water pumps, single-stage single-suction cantilever centrifugal pumps and double-suction centrifugal pumps made in China, in addition to standard diameter impellers, most often have one or two small variants of the impeller (A, B) . If necessary, the unit can also be used to cut the impeller of the bicycle to achieve the purpose of adjusting the operating point of the pump.
Third, variable angle adjustment
Axial flow pumps have low heads and narrow high-efficiency zones. A slight change in the working head of the axial flow pump will cause a significant decrease in working efficiency. Neither throttling nor turning adjustments apply to axial flow pumps. But axial flow pumps have huge wheels, making it easy to install adjustable blades. Adjusting the operating point by changing the installation angle of the axial flow pump blade is called variable angle adjustment
Fourth, variable valve adjustment
For a pumping device equipped with a gate valve in the outlet pipe, when the gate valve is closed, the pipeline characteristic curve becomes steeper because a local resistance is added to the pipeline resistance. Therefore, its operating point moves along the curve of the pump toward the upper left side where the flow rate decreases. The smaller the gate valve is closed, the greater the additional resistance, and the smaller the flow becomes. This method of changing the operating point position of the pump by closing the small gate valve is called variable valve adjustment or throttling adjustment.
Five, shunt regulation
A branch pipe or a bypass pipe is connected to the water outlet pipe of the water pump to lead out part of the water flow to change the operating point of the water pump, which is called shunt adjustment. In principle, the split flow adjustment is the same as that of the vane pump on the branch line. Only the potential of the machine is realized and the pumping efficiency is improved. However, this adjustment requires an additional pipeline, so first of all, calculation must be performed to verify the economics of the adjustment. This situation is the same as a water pump supplying water to the effluent basins of different heights. The axial flow pump unit and the centrifugal pump unit working in series can avoid the overload and vibration of the power machine by applying split flow adjustment during startup.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of Vane Pumps . T series high pressure needle pump is a high performance, low cost pump. Balanced design and lip blade technology are key features; V / Vq series vane pumps have unique filter element design in the blades, and are characterized by maintainability, high efficiency and long service life; our products are widely used in cutting , Plastics, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Welcome to purchase: https://www.china-vanepump.com/
I. Speed adjustment
Changing the speed of the pump can change the performance of the pump to achieve the purpose of adjusting the operating point of the pump. This method of adjustment is called variable speed adjustment.
There are two ways to change the speed of the pump, one is to use a variable speed power machine, and the other is to use a variable speed transmission equipment. The speed of the internal combustion engine can be automatically adjusted according to the load; the methods of variable speed of the motor mainly include frequency conversion, variable resistance, variable pressure, variable capacity adjustment, etc.
Second, reducer adjustment
Turning the outer diameter of the impeller of a centrifugal pump or a mixed flow pump can change the performance of the pump, thereby adjusting the operating point of the pump, and expanding the use of the pump. This adjustment method is called reducing adjustment, also called turning adjustment or cutting adjustment. Turning regulation has been widely used in pump manufacturing. In order to expand the use of water pumps, single-stage single-suction cantilever centrifugal pumps and double-suction centrifugal pumps made in China, in addition to standard diameter impellers, most often have one or two small variants of the impeller (A, B) . If necessary, the unit can also be used to cut the impeller of the bicycle to achieve the purpose of adjusting the operating point of the pump.
Third, variable angle adjustment
Axial flow pumps have low heads and narrow high-efficiency zones. A slight change in the working head of the axial flow pump will cause a significant decrease in working efficiency. Neither throttling nor turning adjustments apply to axial flow pumps. But axial flow pumps have huge wheels, making it easy to install adjustable blades. Adjusting the operating point by changing the installation angle of the axial flow pump blade is called variable angle adjustment
Fourth, variable valve adjustment
For a pumping device equipped with a gate valve in the outlet pipe, when the gate valve is closed, the pipeline characteristic curve becomes steeper because a local resistance is added to the pipeline resistance. Therefore, its operating point moves along the curve of the pump toward the upper left side where the flow rate decreases. The smaller the gate valve is closed, the greater the additional resistance, and the smaller the flow becomes. This method of changing the operating point position of the pump by closing the small gate valve is called variable valve adjustment or throttling adjustment.
Five, shunt regulation
A branch pipe or a bypass pipe is connected to the water outlet pipe of the water pump to lead out part of the water flow to change the operating point of the water pump, which is called shunt adjustment. In principle, the split flow adjustment is the same as that of the vane pump on the branch line. Only the potential of the machine is realized and the pumping efficiency is improved. However, this adjustment requires an additional pipeline, so first of all, calculation must be performed to verify the economics of the adjustment. This situation is the same as a water pump supplying water to the effluent basins of different heights. The axial flow pump unit and the centrifugal pump unit working in series can avoid the overload and vibration of the power machine by applying split flow adjustment during startup.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of Vane Pumps . T series high pressure needle pump is a high performance, low cost pump. Balanced design and lip blade technology are key features; V / Vq series vane pumps have unique filter element design in the blades, and are characterized by maintainability, high efficiency and long service life; our products are widely used in cutting , Plastics, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Welcome to purchase: https://www.china-vanepump.com/
2020年3月23日（月）
Fixed Vane Pumps -Fixed And Variable Pumps: Structural Performance
For novices in the fluid power industry, a lack of understanding between fixed flow and variable flow pump concepts is common. One of the tasks of a hydraulic pump is to convert the input mechanical energy on its shaft into the hydraulic energy of an actuator that can transmit the force somewhere downstream. This force transfer is common for both fixed and variable pumps, but the method transfer is quite different.
The displacement of a pump is determined by the theoretical volume of the displacement that a gear, vane or piston will make in one revolution. If the pump is 30 cc, it would theoretically push 30 ml of fluid in a single revolution, about 1.8 in.3. For a fixed displacement pump, this 30 cm3 will not change no matter how the pump is controlled or what happens downstream. Actually, actual flow will vary based on efficiency, speed and pressure, but this is another matter. If the required flow is less than the rated flow of the pump, the excess flow must be diverted or released into the tank.
Variable displacement pumps have methods to increase or decrease displacement manually, hydraulically, or electronically. The method of changing the displacement depends on the structure of the pump, and between the piston pump and the vane pump, and between the two, the iteration is still different.
The maximum displacement of an axial piston pump is determined by the number of pistons and hole area times the stroke length. Although the stroke length can be fixed, such as most radial and curved shaft piston motors, the stroke can also be varied. Variable displacement axial piston pumps use a swash plate to guide the piston to reciprocate while rotating about the axis of the shaft. The angle of the swash plate relative to the piston determines the length of the piston stroke. In the case of variable pumps, the swash plate is supported by bearings or bushings.
Place an offset piston (and spring) and a control piston on opposite sides of the swash plate. The variable displacement piston pump is designed to be "on-stroke", which means that it wants to pump at full displacement as much as possible. The control piston is operated by an overflow valve in essence. If the downstream pressure rises above the set value of the pressure compensator, it will push out the control piston to reduce the angle of the swash plate. As the swashplate angle decreases, the piston can now move a fraction of its stroke potential. Because the displacement is determined by the area, number and stroke of the pistons, the volume of the pump can now be reduced. If the downstream pressure is still higher than the compensator setting, the stroke will decrease until the swashplate angle is close to zero, at which point the swashplate angle can only pump a sufficient amount to maintain lubrication.
The swashplate angle can be mechanically changed by lever or wheel, but in advanced applications, the electric proportional valve can control the control piston to adjust the pump flow as required. This is an advanced concept used in closed-loop electronic control applications. The proportional pressure valve will adjust the pump's control piston under the guidance of the PLC, thereby providing the precise flow required by the machine under changing conditions.
The working principle of variable displacement pressure compensated vane pump is completely different from that of piston pump. Instead of the reciprocating piston, the rotary set of the vane pump is exposed to a suction chamber and a pressure chamber inside the casing. The blades move outwardly and inwardly within a cam ring that is offset relative to the axis of the rotation group. There is a control piston in the variable vane pump, but this time it pushes towards the cam ring. When the downstream pressure rises, the control piston pushes the cam ring toward the center of the housing, thereby reducing the misalignment between the cam ring and the rotation group. This reduces effective displacement and reduces flow to reduce downstream pressure.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of Fixed Vane Pumps . Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Welcome to buy: https://www.china-vanepump.com/product/
The displacement of a pump is determined by the theoretical volume of the displacement that a gear, vane or piston will make in one revolution. If the pump is 30 cc, it would theoretically push 30 ml of fluid in a single revolution, about 1.8 in.3. For a fixed displacement pump, this 30 cm3 will not change no matter how the pump is controlled or what happens downstream. Actually, actual flow will vary based on efficiency, speed and pressure, but this is another matter. If the required flow is less than the rated flow of the pump, the excess flow must be diverted or released into the tank.
Variable displacement pumps have methods to increase or decrease displacement manually, hydraulically, or electronically. The method of changing the displacement depends on the structure of the pump, and between the piston pump and the vane pump, and between the two, the iteration is still different.
The maximum displacement of an axial piston pump is determined by the number of pistons and hole area times the stroke length. Although the stroke length can be fixed, such as most radial and curved shaft piston motors, the stroke can also be varied. Variable displacement axial piston pumps use a swash plate to guide the piston to reciprocate while rotating about the axis of the shaft. The angle of the swash plate relative to the piston determines the length of the piston stroke. In the case of variable pumps, the swash plate is supported by bearings or bushings.
Place an offset piston (and spring) and a control piston on opposite sides of the swash plate. The variable displacement piston pump is designed to be "on-stroke", which means that it wants to pump at full displacement as much as possible. The control piston is operated by an overflow valve in essence. If the downstream pressure rises above the set value of the pressure compensator, it will push out the control piston to reduce the angle of the swash plate. As the swashplate angle decreases, the piston can now move a fraction of its stroke potential. Because the displacement is determined by the area, number and stroke of the pistons, the volume of the pump can now be reduced. If the downstream pressure is still higher than the compensator setting, the stroke will decrease until the swashplate angle is close to zero, at which point the swashplate angle can only pump a sufficient amount to maintain lubrication.
The swashplate angle can be mechanically changed by lever or wheel, but in advanced applications, the electric proportional valve can control the control piston to adjust the pump flow as required. This is an advanced concept used in closed-loop electronic control applications. The proportional pressure valve will adjust the pump's control piston under the guidance of the PLC, thereby providing the precise flow required by the machine under changing conditions.
The working principle of variable displacement pressure compensated vane pump is completely different from that of piston pump. Instead of the reciprocating piston, the rotary set of the vane pump is exposed to a suction chamber and a pressure chamber inside the casing. The blades move outwardly and inwardly within a cam ring that is offset relative to the axis of the rotation group. There is a control piston in the variable vane pump, but this time it pushes towards the cam ring. When the downstream pressure rises, the control piston pushes the cam ring toward the center of the housing, thereby reducing the misalignment between the cam ring and the rotation group. This reduces effective displacement and reduces flow to reduce downstream pressure.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of Fixed Vane Pumps . Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Welcome to buy: https://www.china-vanepump.com/product/
2020年3月16日（月）
Hydraulic Pumps Wear Check
If the Hydraulic Pumps is used for a long time, it will also cause the hydraulic pump to wear. What causes the hydraulic pump to wear? Chinese hydraulic pump manufacturer states:
When the hydraulic pump is in operation, check whether the hydraulic pump has a problem. You can observe whether the hydraulic pump is freely lowering. When the hydraulic pump is lowering, you need to check the oil cylinder. If the seal is found to be worn, you need to replace it in time; check Whether the hydraulic pump is worn can also be started by inspecting the operating valve. You can check whether the valve core is worn. If it is worn, it needs to be replaced. Through different detection methods, different wear problems can be found, which requires different methods to deal with.
We all know that hydraulic pumps are used in the operation of many mechanical equipment. Such pumps have also become good helpers when mechanical equipment is operating. When many machinery and equipment are in operation, it can greatly improve the progress of the project, and for many enterprises, it also brings a lot of help. In order to better maintain the hydraulic pump, it is also necessary to maintain the hydraulic oil.
When the hydraulic pump is in operation, the temperature of the hydraulic oil should be controlled below 70 degrees Celsius as much as possible. Of course, it can be controlled below 60 degrees Celsius! The use of hydraulic oil also needs to control pollution. If the hydraulic pump is used because the hydraulic oil If it is contaminated, some problems will occur when the hydraulic pump is used. In order to avoid this kind of situation, it is necessary to take good care of the hydraulic oil.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of hydraulic pumps. Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, Automatic production lines and other fields. Welcome to buy: https://www.china-vanepump.com/product/t-series-pin-vane-pumps-with-high-pressure/
When the hydraulic pump is in operation, check whether the hydraulic pump has a problem. You can observe whether the hydraulic pump is freely lowering. When the hydraulic pump is lowering, you need to check the oil cylinder. If the seal is found to be worn, you need to replace it in time; check Whether the hydraulic pump is worn can also be started by inspecting the operating valve. You can check whether the valve core is worn. If it is worn, it needs to be replaced. Through different detection methods, different wear problems can be found, which requires different methods to deal with.
We all know that hydraulic pumps are used in the operation of many mechanical equipment. Such pumps have also become good helpers when mechanical equipment is operating. When many machinery and equipment are in operation, it can greatly improve the progress of the project, and for many enterprises, it also brings a lot of help. In order to better maintain the hydraulic pump, it is also necessary to maintain the hydraulic oil.
When the hydraulic pump is in operation, the temperature of the hydraulic oil should be controlled below 70 degrees Celsius as much as possible. Of course, it can be controlled below 60 degrees Celsius! The use of hydraulic oil also needs to control pollution. If the hydraulic pump is used because the hydraulic oil If it is contaminated, some problems will occur when the hydraulic pump is used. In order to avoid this kind of situation, it is necessary to take good care of the hydraulic oil.
Zhejiang Yongling Hydraulic Machine Co , Ltd . is a professional China manufacturer and supplier of hydraulic pumps. Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, Automatic production lines and other fields. Welcome to buy: https://www.china-vanepump.com/product/t-series-pin-vane-pumps-with-high-pressure/
2020年3月9日（月）
Installation And Use Of Fixed Vane Pumps
1. When the pressure of the pump exceeds 16MPa and the displacement is "4", "6", "8", the speed should be greater than 1450 r / min.
2. Reduce the negative pressure at the inlet of single-row pump or double-row pump at high speed and large displacement.
3. The numbers in parentheses are those using phosphate ester oil and water-containing hydraulic oil.
4. It is recommended to drive at a speed of 1000r / min under the strict requirements of low noise.
5. When the working fluid is a phosphate ester fluid, please use a special seal (FPM) when ordering, and add the prefix [F-] before the specified model.
6. Input power is available under 16 MPa and 1500r / min working conditions.
Zhejiang Yongling Hydraulic Machine Co , Ltd is a professional China manufacturer and supplier of Fixed Vane Pumps . Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Welcome to purchase: https://www.china-vanepump.com/
2. Reduce the negative pressure at the inlet of single-row pump or double-row pump at high speed and large displacement.
3. The numbers in parentheses are those using phosphate ester oil and water-containing hydraulic oil.
4. It is recommended to drive at a speed of 1000r / min under the strict requirements of low noise.
5. When the working fluid is a phosphate ester fluid, please use a special seal (FPM) when ordering, and add the prefix [F-] before the specified model.
6. Input power is available under 16 MPa and 1500r / min working conditions.
Zhejiang Yongling Hydraulic Machine Co , Ltd is a professional China manufacturer and supplier of Fixed Vane Pumps . Our products are widely used in cutting, plastic, forging, engineering, leather, pressure, metallurgy, agriculture, transportation machinery and machine tools, hydraulic stations, automatic production lines and other fields. Welcome to purchase: https://www.china-vanepump.com/
