【 Weak current College 】 gear pump instead of a piston pump function of the technical analysis---Power By 【 China power house network 】

Due to the constant displacement of structural constraints, typically think gear pump can only be made use of constant flow hydraulic source. However, the attachment into thread connection combination valve programme for improving its functionality, lower system costs and improve system reliability is valid and, therefore, gear pumps performance close to expensive, complex piston pump.

For example in pump installation directly on the valve, can save between pump and direction, thus controlling the pipeline. Less pipe and fittings reduces leakage and improves the reliability of work. And pump itself installed valve reduces the pressure of the loop, the loop to improve their work performance. Here are some may enhance the basic functionality of the gear pump circuit, some of which were proved feasible basic circuit, and some of the innovative research.

Uninstall circuit

Uninstall components in large flow pump and low-power single pump. Liquid from two pump outlet discharge, to achieve predetermined pressure and/or flow rate. At this point, the big flow pump will flow from its export cycle to the entrance, which reduces the output of the pump to the system, magnetic flux power reduced to slightly higher than the high part of the work of the desired value. Flow reduction percentage depends on you do not uninstall the displacement ratio of the total displacement, combination or thread connection unloading valve reduces and even eliminates the pipe, duct and accessories and other possible leaks.

The most simple uninstall components by artificial manipulation. Spring allows unloading valve is switched on or off, when a control signal to the valve, the valve's switching-off State is good. Lever or other mechanical bodies is the manipulation of this valve in easiest way.
Import control (pneumatic or hydraulic) unloading valve is manipulating the way of a modified, because this is the valve can be remote controlled. Its greatest progress is the use of electrical or electronic customs control of solenoid valve, it is not only available remote control and automatic control of available microcomputer, is usually considered that such a simple uninstall technology is the best application.

Manually operated unloading components used in the operation and the need for fast and high-traffic and fast operation, high-traffic and you want to precisely control and reduce the flow of the circuit, for example, the rapid expansion of the boom circuit. Figure 1 circuit of the uninstall function without manipulating the signal (left), the circuit has been output flow. For normally open valve, normal next loop will output low flow rate. Pressure sensing uninstall is the most common scenarios. As shown in Figure 2, the role that unloading valve spring is in the high-traffic location (left). Circuit pressure reaches the overflow valve presetting value, the relief valve opens, unloading valves in the hydraulic and role switch to its small flow position (right). Unloading valve pressure sensor is essentially a system pressure is automatically uninstalled components of unloading, generally used to measure distance meter split and hydraulic Vice.

Flow sensor uninstall loop unloading valve by spring press to large flow rate position (left '). This valve fixed orifice size press equipment engine best rate desired flow. If the engine speed range beyond this best, the throttle orifice pressure drop will increase, so will uninstall the valve position shift to low flow rate (right). Therefore large flow pump made of adjacent components on the largest flow restrictor size, so the circuit low energy consumption, smooth a low cost. This is a typical application circuit, circuit flow up to the best qualified to enhance overall system performance, or qualified machine high speed during circuit pressure. Often used for spam delivery truck, etc.

Pressure and flow sensing uninstall circuit of unloading valve by spring to flow position (left), whatever its intended pressure or flow will be uninstalled. Equipment in idling or working speeds are complete high-pressure work. This feature reduces unnecessary traffic, thus reducing the required power. Because the circuit has a wide range of load and speed changes, it is often used for mining equipment.

With the power of integrated pressure sensing circuit, it uninstalled by two sets of slightly changing pressure sensing unloading pump, two groups of pump driven by the same prime mover, each magnetic accept another uninstall pump guide-uninstalling the signal. This way our sensor called interactive sensor, it can make a set of pump work under pressure and the other level pump flow. Two overflow valve according to each circuit special pressure adjustment, so that one or two pumps to uninstall. This scenario reduces power requirements, it may use the small capacity low prime mover.

Shows the load sensing uninstall circuit. When the main control valve control valve (vena) no load sensing signal, all flow through the pump valve 1, valve 2 row back into the tank; when applied to the control valve load sensing signal, the pump to the feeding circuit; when the pump output pressure exceeds the load sensing valve pressure intended value, pump only provide work to the circuit, but the extra traffic flow through the valve 2 throttle position (upper) by-pass back into the tank. With load sensing element of gear pumps compared with piston pump, with a low-cost, strong resistance to pollution and low maintenance requirements.

Priority flow control

Whether the pump speed, pressure or flow of the branch needs, setting a flow control valve total guarantees that the equipment work flow. In Figure 7 shows the circuit of the pump output flow must be greater than or equal to a circuit required flow, secondary flow can make it to use or to the fuel tank. Setting a flow valves (proportional valves) is a control and hydraulic pump to save the pipeline and eliminate external leakage, and reduced costs. This kind of gear pump circuit of typical applications are often visible on truck cranes to the steering mechanism, it eliminates a pump.

Load sensing flow control valve function and setting a flow control function is very similar: that is, whether the pump speed, pressure or suction required flow size slip shall provide a flow. But shown in scenario, only one oil port to a circuit to provide the necessary flow until the maximum adjustment value. This circuit can replace the standard one flow control circuit and get maximum output flow. No load circuit pressure lower than the fixed value once flow control scheme, so the circuit temperature low, no-load power consumption low. Load sensing than column flow control valve and a flow control valve, the typical application is the power steering body.

Bypass flow control
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For bypass flow control, pump speed or high or low working pressure, the pump on a predetermined maximum value to the system for liquid, excess rows back to the entrance of the fuel tank or pump. This option limits the system flow that has the best performance. The advantage of scale through the circuit to control the maximum adjustment of flow and reduce cost; the pump and valve combined into one, and through the pump bypass control so that the circuit pressure to a minimum, from the surface to reduce pipeline and leaks.

Bypass flow control valve can be used with qualified work flow (work speed) range of mission-load sensing valve design together. This type of gear pump circuit, commonly used to limit the hydraulic control to the engine up to the best speed of garbage in trucks or power steering pump circuit, can also be used for stationary equipment.

Dry suction valve

Dry suction valve is one of my air-controlled hydraulic valve, it is used to pump oil throttle, hydraulic load device, only the minimal flow through the pump; in a load-time, full flow suction pump. This circuit can save the pump and the prime mover of the clutch, thereby lowering costs, reducing no-load power consumption, very small by circuit traffic has maintained the original motive power equipment. In addition, also reduces the pump in no-load noise. Dry suction valve circuit can be used by internal combustion engine driven any vehicle switch type hydraulic system, such as garbage loading trucks and industrial equipment.

Choice of hydraulic pump

At present, the gear pump pressure is drawing to a close, piston pump, combined load sensing programme for gear pump provides variable possibilities, this means that the gear pump and pump clear boundaries between original becoming increasingly blurred. Reasonable choice of hydraulic pump programme one of the deciding factor is the cost of the entire system, and expensive compared to the piston pump, pump to its lower cost, the circuit is simple, low filtration requirements, as many applications feasible options.