What is the difference between an open pump and a closed pump?

Open pump: the oil port is large and small, the suction port is generally high, and the oil outlet is a little lower.

Closed Pump: Both ports are the same size.

1.The cycle of the open pump system is: oil tank - pump - control valve - user end (- control valve) - oil tank.

2.The cycle of the closed pump system is: pump - user end - pump.

3.The circulation main line of an open pump is open (at the tank) and that of a closed pump is closed.

4.The open pump can only transmit power in the forward direction, and the braking can only be throttled through the control valve; The closed-circuit pump transmits power in both directions and can realize prime mover braking.

5.In an open circuit, the pump output is generally unidirectional. Reversing by reversing valve.

6.In a closed circuit, the pump output is generally bidirectional. By adjusting the swash plate or stator.

Eccentric commutation. 7.The concept of open pump and closed pump is generally for swash plate axial piston pump, especially for closed pump, it seems that as far as I know, there is only swash plate type, because changing the swash plate angle from the positive maximum angle to the negative maximum angle, the swash plate inertia mass is small, easy to change, and the response is fast.

8.For open pumps and closed pumps, the variable mode is basically the same, all by changing the angle of the swash plate to achieve, as for the variable requirements are according to different working conditions, the pressure compensation you are talking about, load sensitivity These variable requirements are applied in both open pumps and closed pumps, in fact, it is a valve-controlled feedback system.

9.In most cases, open pumps are generally selected, because the economy is relatively better under the premise of meeting the requirements of the working conditions. Under the working conditions that have clear requirements for the volume of the fuel tank, such as mobile machinery, lifting machinery.

Because of the limited space, it is necessary to use a closed pump, because it eliminates the need for hydraulic valves and some pipelines, so the volume of the fuel tank is relatively reduced.

10.An open system refers to a hydraulic pump.

The oil is sucked from the oil tank, and after the oil passes through various control valves, the hydraulic actuator is driven, and the oil is returned to the oil tank through the reversing valve. The structure of this system is relatively simple, which can play the role of heat dissipation and precipitation of impurities in the fuel tank, but because the oil is often in contact with the air, the air is easy to penetrate into the system, resulting in the unstable movement of the mechanism. The open system has a large oil tank and good self-priming performance of the oil pump.

11.In the closed system, the inlet pipe of the hydraulic pump is directly connected to the return pipe of the actuator, and the working liquid is circulated in the pipeline of the system. Its structure is compact, there is less chance of contact with air, and the air is not easy to penetrate into the system, so the transmission is relatively stable.

The variable mechanism of the variable speed and reversing* adjustment pump or motor of the working mechanism is realized, which avoids the hydraulic shock and energy loss that occurs in the reversing process of the open system. However, the closed system is more complex than the open system, because there is no oil tank, and the heat dissipation and filtration conditions of the oil are poor.

An open pump means that the impeller is open, and a closed pump means that the impeller is closed, simply put, the open impeller has only one side, and the closed impeller is two-sided.

Good and bad: Open impellers convey liquids containing fibers and large particles. The closed impeller flow channel is relatively narrow, which is not suitable for conveying liquids containing large particles.

The open circulating water pump is relative to the closed circulating water pump. If the circulating water cold water is introduced from the outside, and the hot water after cooling the equipment is discharged to the outside, all the circulating water is introduced from the external rivers, water towers, reservoirs, lakes, etc., and then discharged to these water sources, which is the open system, and the circulating water pump used for this open system is the open circulating water pump. Some equipment has requirements for circulating water quality, and the external water quality can not meet the requirements, so the qualified water is used to cool the equipment first, the hot water is returned to a heat exchanger, and the cold water outside the heat exchanger is used to cool the hot water inside, and the hot water of the heat exchanger is cooled and then sent back to the equipment to cool the equipment.

The closed pump can be used as an open pump, but a certain oil port of the main oil pump of the closed pump and the suction port of the oil replenishment pump must be connected to the oil tank, and the flushometer must also be installed. The displacement control device also adds a mechanical limit to prevent the swash plate from acting in the opposite direction under abnormal conditions. The oil of the open hydraulic system motor or cylinder is returned to the oil tank, and the pump directly sucks oil from the oil tank; The oil returned by the closed hydraulic system motor or cylinder does not return to the oil tank and goes directly to the oil inlet of the pump.

There are many types of centrifugal pumps, and the common classification methods are as follows: 1. According to the impeller suction method: single-suction centrifugal pump, double-suction centrifugal pump;

2. According to the number of impellers: single-stage centrifugal pump and multi-stage centrifugal pump;

3. According to the impeller structure: open impeller centrifugal pump, semi-open impeller centrifugal pump, closed impeller centrifugal pump;

4. According to the working pressure: low-pressure centrifugal pump, medium-pressure centrifugal pump, high-pressure centrifugal pump;

5. According to the position of the pump shaft: horizontal centrifugal pump side vertical centrifugal pump.

There are three types of impellers for water pumps: open, closed and semi-closed.

The open impeller has no cover plate on both sides of the blade, which is simple to manufacture and easy to clean, and is suitable for conveying materials containing a large amount of suspended solids, with low efficiency and low pressure of the liquid conveyed; The semi-closed impeller has no cover plate on one side of the suction inlet, but has a cover plate on the other side, which is suitable for conveying materials that are easy to precipitate or contain particles, and the efficiency is also low; Closed impeller has front and rear covers on both sides of the impeller, which is highly efficient and suitable for conveying clean liquids without impurities. The general centrifugal pump impeller is mostly of this type.

Comparison of open, semi-open and closed: From the actual pump, the open type (i.e., equivalent to the removal of the front and rear covers of the closed impeller) has the lowest efficiency because the volumetric efficiency cannot be guaranteed. The head flow of the pump should be reduced (open type is larger than closed type return flow).

Semi-open (equivalent to a closed impeller with one side removed from the front or rear cover) efficiency and head are in the middle. The closed impeller has the smallest return flow (generally designed with front and rear sealing rings), and the efficiency, flow rate and head are the highest.

The main difference between open and closed pumps is the way in which the pump is connected to its working environment.

The pump body of the open pump is openly connected to the environment, that is, there is no sealed connection between the pump body and the inlet and outlet pipelines, so the fluid can be freely exchanged between the working environment of the pump and the surrounding environment, and the operating status of the pump can be directly observed and monitored. Open pumps are typically used to convey water and other non-corrosive liquids such as air conditioning water, tap water, etc.

The connection between the pump body and the environment of the closed pump is sealed, and the connection between the pump body and the inlet and outlet pipelines is sealed, so there is no channel for exchanging fluids between the working environment of the pump and the surrounding environment, and the fluid in the pump cannot leak out, and the nuclear withering can only be output through the outlet pipeline of the pump. Liquid's closed pumps are usually used to transport corrosive media or harmful gases, such as acid and alkali liquids, petrochemical media, etc.

Therefore, the difference between an open pump and a closed pump is the connection between the pump body and the inlet and outlet pipes, while the specific application of the pump depends on the working environment of the pump and the characteristics of the medium being conveyed.

To be precise, it should be: open pump means that the impeller is open, closed pump means that the impeller is closed, in simple terms, the open impeller has only one side, and the closed impeller is two-sided.

Good and bad: Open impellers convey liquids containing fibers and large particles. The closed impeller flow channel is relatively narrow, which is not suitable for conveying liquids containing large particles.