Proper selection and operation of the pump will have a significant impact on the overall performance, operating efficiency and operating costs of the system.
In all pump types, you will hear "Pumps do not suck or pump." Although pumps come in a variety of shapes and sizes and different operating mechanisms, they can all do one thing-generate flow by transferring mechanical energy to the velocity of the fluid.
To understand this, we must first know that the energy comes from the motor. Electric motors absorb electrical energy and convert it into torque called torque. There is a relationship between horsepower, speed and torque. The following formula will make it clear.
Torque is the mechanical energy that is transmitted from the motor shaft to the pump shaft and then converted to fluid velocity.
Because the pump has the highest rated speed, most industrial hydraulic systems use electric motors with a nominal rating of 1200 rpm (actually 1,140 rpm) or a nominal rating of 1800 rpm (actually 1,750 rpm). On mobile hydraulic systems using internal combustion engines, variable speed drives are used to regulate the output speed. It is important that the operator does not fall below the minimum speed limit of the pump or exceed its maximum speed limit.
If people understand Boyle’s law, they can understand the pumping action of any hydraulic pump:
Bower’s Law—At a constant temperature and constant mass, absolute pressure is inversely proportional to gas volume.
In short, as the volume decreases, the pressure increases (exhaust stroke). As the volume increases, the pressure decreases (intake stroke).
In the case where the capacity of the dynamic pressure pump (gpm) decreases with the increase of the pressure of the head, the positive displacement pump provides a constant output flow (gpm) regardless of the pressure of the head.
The size of a positive displacement pump is expressed in cubic inches when the drive shaft makes one revolution.
Another way to indicate the size of a positive displacement pump is the rated flow at a specific drive speed. Hydraulic pump manufacturers simply refer to these pump sizes as 8 gpm, 10 gpm, etc.
Theoretically, a pump of 25 inches per revolution would deliver 25 inches of fluid. In fact, the output of the pump will decrease due to internal slip (fluid flows from the output of the pump to the input of the pump). For a given gap, the higher the outlet pressure, the greater the slip.
The mechanical efficiency can be derived by dividing the theoretical torque value by the actual torque required to drive the pump.
Overall efficiency includes volumetric efficiency and mechanical efficiency.
It is important that operators and maintenance personnel have a thorough understanding of these values and their relationship to the system.
A fixed displacement pump works in it. As long as the following conditions do not need to be met, you can choose to use a fixed displacement pump:
Maintain system pressure on stalling actuators
During the cycle, the actuator must
Relatively low speed
Circuits run in different speed ranges
Pump cannot be unloaded through the circuit
You must choose a pump of exact size. The fixed displacement pump is a positive displacement pump. The displacement (gpm) cannot be changed only by changing the driving speed of the pump.
Zhejiang Yongling Hydraulic Machinery 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/
In all pump types, you will hear "Pumps do not suck or pump." Although pumps come in a variety of shapes and sizes and different operating mechanisms, they can all do one thing-generate flow by transferring mechanical energy to the velocity of the fluid.
To understand this, we must first know that the energy comes from the motor. Electric motors absorb electrical energy and convert it into torque called torque. There is a relationship between horsepower, speed and torque. The following formula will make it clear.
Torque is the mechanical energy that is transmitted from the motor shaft to the pump shaft and then converted to fluid velocity.
Because the pump has the highest rated speed, most industrial hydraulic systems use electric motors with a nominal rating of 1200 rpm (actually 1,140 rpm) or a nominal rating of 1800 rpm (actually 1,750 rpm). On mobile hydraulic systems using internal combustion engines, variable speed drives are used to regulate the output speed. It is important that the operator does not fall below the minimum speed limit of the pump or exceed its maximum speed limit.
If people understand Boyle’s law, they can understand the pumping action of any hydraulic pump:
Bower’s Law—At a constant temperature and constant mass, absolute pressure is inversely proportional to gas volume.
In short, as the volume decreases, the pressure increases (exhaust stroke). As the volume increases, the pressure decreases (intake stroke).
In the case where the capacity of the dynamic pressure pump (gpm) decreases with the increase of the pressure of the head, the positive displacement pump provides a constant output flow (gpm) regardless of the pressure of the head.
The size of a positive displacement pump is expressed in cubic inches when the drive shaft makes one revolution.
Another way to indicate the size of a positive displacement pump is the rated flow at a specific drive speed. Hydraulic pump manufacturers simply refer to these pump sizes as 8 gpm, 10 gpm, etc.
Theoretically, a pump of 25 inches per revolution would deliver 25 inches of fluid. In fact, the output of the pump will decrease due to internal slip (fluid flows from the output of the pump to the input of the pump). For a given gap, the higher the outlet pressure, the greater the slip.
The mechanical efficiency can be derived by dividing the theoretical torque value by the actual torque required to drive the pump.
Overall efficiency includes volumetric efficiency and mechanical efficiency.
It is important that operators and maintenance personnel have a thorough understanding of these values and their relationship to the system.
A fixed displacement pump works in it. As long as the following conditions do not need to be met, you can choose to use a fixed displacement pump:
Maintain system pressure on stalling actuators
During the cycle, the actuator must
Relatively low speed
Circuits run in different speed ranges
Pump cannot be unloaded through the circuit
You must choose a pump of exact size. The fixed displacement pump is a positive displacement pump. The displacement (gpm) cannot be changed only by changing the driving speed of the pump.
Zhejiang Yongling Hydraulic Machinery 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/
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