Analysis and elimination of cavitation in hydraulic pump

There are many problems in the process of hydraulic work, which requires the hands and users to master some basic skills, and can solve the problem at the critical moment.

High pressure hydraulic system, compact structure, light weight, small size, can absorb the external shocks, and the damping effect of impact load has good adaptability so the main characteristics of the new hydraulic obtained widely described in this article in the engineering machinery vehicle steering system is to shift the flow stability, and not change with the engine the change in speed; straight line driving, steering pump unloading, small energy loss and high efficiency; the volume ratio of the accumulator is small, easy to install.

To hydraulic oil as the working medium of hydraulic system, when the absolute pressure of oil is lower than the air pressure fluid separation, dissolved air in oil will be separated by the large amount of bubbles, which will produce cavitation cavitation harm to the hydraulic system, the liquidity of oil is accompanied by destruction the noise and vibration, low pressure area separated bubble mixed with oil, with the oil flow in the high pressure area, will produce high temperature and pressure local impact instantaneous break, on one hand the performance of the oil change, at the same time, on the surface of metal forming chemical corrosion, with pressure under the impact, the metal surface will be fast erosion and damage.

From the point of view of cavitation, the condition of forming cavitation must be the absolute pressure below the oil in the oil.

In the hydraulic system, what will appear under the absolute pressure of oil is lower than the air separation pressure, of course, this situation a lot, such as oil or liquid through the throttle valve port, high-speed jet, the formation of local low pressure; too much oil resistance or pump, the suction side pressure pump is lower than the pressure of oil air separation the.

In addition, in the process of movement of the hydraulic cylinder suddenly shut down its oil inlet, due to inertia loads, an oil hydraulic cylinder side may produce the absolute pressure is lower than the air separation pressure so that under certain conditions, many parts of the hydraulic system will produce cavitation of the hydraulic system of the great harm in the design of hydraulic the use of hydraulic components and hydraulic system and mechanical, must produce as much as possible to avoid cavitation.

Here the harm caused by cavitation in IP-750 pressure die casting machine, to our attention, and to avoid the 750 tons die casting machine IP-750 die casting machine production department of Italy in the days after work, the hydraulic pump for the VICKERS double vane pump, the working medium is water glycol, the allow the viscosity is about 35m2/s (at 38 C case) on the evening of February 15, 2000 work, die casting machine automatically shut down due to a lot of automatic IP-750 die casting machine, such as oil and liquid enough hydraulic pump vacuum suction, motor overload, high pressure etc..

When the equipment is forced to cancel the alarm (which is permitted by the equipment) to restart the hydraulic pump, only 2- 3S time, the equipment is shut down again. Check the oil level and find the oil level is low. But as for the alarm to stop considering the start and the hydraulic system of hydraulic pump liquid filling device will make the level further decline in energy storage, so to the fuel tank of about 200L, and then start the hydraulic pump device is still in 2~ 3S after shutdown, the fault has not ruled out, when the pressure relay check the pump suction port, found the hydraulic pump is started immediately after the action, the pressure relay for negative pressure relay.

So, the preliminary determination is too large due to hydraulic pump oil resistance, caused by negative pressure relay, thus stopping the cause of excessive hydraulic pump suction resistance is generally as follows: 1) filter, filter design flow capacity, filter blockage caused by the current lack of capacity and steering system. By adjusting the pressure regulating screw 9, the preload of the poppet valve spring 7 to the poppet valve 6 can be changed, so that the maximum pressure of the steering system can be adjusted.

When pressure adjustment, the 12 plug unloaded, loaded on gauge couplings, can debug pressure, when the engine speed is 1500r/min, regulating the pressure screw, the pressure gauge readings showed 7. 35MPa4 conclusion hydraulic steering system is to transfer the force and movement of the liquid as working medium, working pressure is far higher than the mechanical drive and pneumatic drive, high sensitivity, hydraulic transmission energy to make more directly and quickly transferred to the desired position.

More details of goods, welcome to the construction machinery home, welcome to inquire details: 13705210834