Manifold block

Manifold Block hydraulic system common faults and troubleshooting – hydraulic system noise, vibration, how to do

Manifold Block hydraulic system common faults and troubleshooting – hydraulic system noise, vibration, how to do


Manifold block hydraulic system is composed of many elastomers. Under the action of impact force, rotating unbalance force, changing friction force, changing inertia force and elastic force, each elastomers will produce resonance and vibration, accompanied by noise.


Performance one, pump noise, vibration


The hydraulic pump is the main noise source in Manifold Block hydraulic station, and the fluid noise of the hydraulic pump is mainly caused by the periodic change of the pressure and flow of the hydraulic pump and cavitation phenomenon. In the hydraulic pump suction and oil injection cycle, periodic pressure and flow changes, stroke pressure pulse, resulting in hydraulic vibration noise.


Phenomenon 1. Cavitation occurs in the pump


A. Cause of failure: the oil temperature is too low or the viscosity is too high;


Elimination method: heating oil or replace the viscosity of a relatively low number of hydraulic oil (anti-wear hydraulic oil: 32 in winter, 46 in summer oil).


B. Cause of failure: the suction pipe is too long, too thin, and too many elbows;


Elimination method: increase the diameter of the corresponding tubing to avoid bending the tubing, reduce the corresponding loss and prevent air infiltration.


C. Cause of failure: the oil inlet filter is too small or blocked;


Elimination method: clean the filter frequently to prevent blocking. In the selection, also choose the appropriate filter.

The filter


D. Cause of failure: the pump is too high from the liquid level;


Elimination method: change the pump installation position.


E. Fault cause: The auxiliary pump is faulty;


Elimination method: replacement or repair.


F. Cause of failure: the pump speed is too fast;


Elimination method: increase the hydraulic pump, reduce the motor revolution.


Phenomenon 2. Bubbles in the oil


A. Cause of failure: improper selection of oil;


Elimination method: replace the oil.


B. Cause of failure: the return pipe in the oil tank is at the liquid level;


Elimination method: the tube is extended below the liquid level.


C. Cause of failure: The tank liquid level is too low;


Elimination method: oil to the specified range (general oil level height is 0.8 times of the tank).


D. Cause of failure: the inlet pipe joint enters air;


Elimination method: replace or tighten the joint.


E. Cause of failure: pump shaft oil seal damage;


Elimination method: replace the oil seal.


Replace the oil seal

F. Fault cause: The system exhaust is not good;


Elimination method: re-exhaust.


Phenomenon 3. Pump wear, damage or low coaxiality between pump and prime mover


A. Replacement or repair; B. System adjustment


Performance two, hydraulic motor noise


1. The pipe joint seal is bad;


Elimination method: change the seal.


2. The oil motor is worn or damaged;


Elimination method: replacement or repair.


3. Low coaxiality between oil motor and working machine;


Elimination method: readjust.


Performance three, hydraulic cylinder noise


Cause of failure: Air enters the cylinder;


Elimination method: good air exhaust.


Performance four, overflow valve screams


The pressure and flow pulsation of Manifold Block hydraulic station is determined by its own structure. Pressure pulsation is a kind of exciting force. If all kinds of valves in the hydraulic station are not firmly installed, they will vibrate under the action of this exciting force and produce noise. In addition, the oil filter is not clean on its high pressure oil throttling action and fluid noise, the one-way valve selection is unreasonable, the liquid flow is one-way valve, its valve is easy to produce vibration caused by noise. When the reversing valve suddenly reverses direction, the flow rate of hydraulic oil suddenly changes, causing pressure shock. Resulting in vibration and noise.


1. The pressure adjustment is too low or too close to other valves;


Elimination method: re-adjust, assemble or replace.

Readjust, assemble, or replace

2. Poppet valve, seat wear;


Elimination method: replacement or repair.


Performance five, pipe noise


The pipe itself is not a source of vibration. If the selection and installation of the pipe are not reasonable, resonance will be generated under the action of the pressure pulsation of the hydraulic oil, and the noise will be very large.


Cause of failure: oil flow violent flow;


Elimination method a. Thickening the pipe so that the flow rate control word is within the allowable range.


B. Use less pipe with more elbow and use the bend with small curvature;


C. Use rubber hose;


D. Right Angle elbow or tee shall not be used where the oil flow is disorderly;


E. Use muffler, accumulator, etc.


Performance six, pipe vibration


1. The pipeline is long and badly fixed;


Elimination method: add pipe clamp, add anti – vibration pad and install pressure plate.


2. Pipeline vibration and noise caused by bad working of relief valve, unloading valve, hydraulic control check valve, balance valve and direction valve;


Elimination method: add throttle valve in the control pipe or return pipe; Select components with pilot unloading function; Using electrical control method, so that more than two valves can not simultaneously reverse.


Performance seven, tank vibration


1. The structure of the oil tank is bad;


Elimination method: the thickening box plate is added to the side plate and the bottom plate to change the shape or position of the end of the oil return pipe.


2. The pump is installed on the oil tank;


Elimination method: the pump should not be installed on the tank, the motor and the pump should be installed separately on the base, and the tank is separate.


3. No anti-vibration measures are available.


Elimination method: at the foot of the tank, the base of the pump to increase the anti-vibration pad.

Problems to be paid attention to when disassembling Manifold Block hydraulic system

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