2019年11月3日星期日

Four Causes of Pump Vibration

There are many reasons that lead to the vibration of the unit and pumping station buildings. Some of the factors are related to both the interaction and the interaction. In summary, there are mainly the following four reasons.
1, electrical aspects

The motor is the main equipment of the unit. The internal magnetic unbalance of the motor and other electrical system disorders often cause vibration and noise. Such as asynchronous motor in operation, due to the stator rotor harmonic magnetic flux interaction between the stator and rotor radial alternating magnetic force, or large synchronous motor in operation, the rotor center of the rotor is inconsistent or in all directions air gap difference Exceeding allowable deviation, etc., may cause the motor to vibrate periodically and make noises.

2, mechanical aspects

Motor and pump rotating parts quality imbalance, shoddy, poor installation quality, unit axis asymmetry, allowance exceeds the allowable value, poor mechanical strength and rigidity of parts, bearings and seals wear damage, and the critical speed of the pump appeared with the unit The natural frequency has been caused by resonance, etc., will have a strong vibration and noise.

3, hydraulic aspects

Pump inlet flow velocity and pressure distribution is not uniform, the pump import and export of working fluid pressure pulsation, flow around the liquid, bias and decoupling, non-fixed conditions and various causes of pump cavitation, are common cause pump vibration s reason. The sudden pressure changes in the water pipe and the water hammer effect caused by the dynamic transition process such as start and stop of pumps, valve opening and closing, change of working conditions and emergency stop of accidents also frequently cause vibration of pumping stations and generating units.

4, hydraulic and other aspects

Inconsistent design of the inflow channel of the unit or its incompatibility with the unit, improper depth of inundation of the pump, unreasonable sequence of starting and stopping of the unit, etc. will worsen the influent conditions, generate whirlpool, induce cavitation or aggravate the vibration of the unit and pump room. If the unit with damaging siphon vacuum cut-off is in operation, if the air in the hump section is entangled with air, it will take too long to form a siphon; Water pump and motor base uneven subsidence or the basis of the poor rigidity and other reasons, will lead to unit vibration.

Electric grab Bridge Crane is mainly comprised of box-shaped bridge, grab crab (Grab Bucket), trolley travelling mechanism, cab and electric control system. The load handing device is the grab which is able to capture bulk materials.

The grab cab has switching mechanism and lifting mechanism. The grabs are separately hung over the switching mechanism and lifting mechanism with four steel wire ropes. The switching mechanism drives the grab to close to grab material. When the grab is closed, the lifting mechanism shall be started immediately to hoist the four evenly loaded steel wire ropes. Discharging only needs to start the switching mechanism, which opens the grab to pour materials.

Except the lifting mechanism, the Overhead Crane is basically the same as the bridge crane with hook.

overhead Grab Crane

Bridge crane with grab bucket

overhead Grab Crane


Specification:

Lifting weight

t

10+10

16+16

25+25

working class

A7

A6

A6

span

mm

25

34

25

33

25

Max. Lifting height

16

16

10

16

10

speed

lifting

m/min

12.6

14.8

16

15.4

travelling

travelling of grab

42.2

42.2

39

48

40

hang beam

travelling of trolley

85.2

85.2

106

101

107

turn round

r/min

1.36

1.36

1.36

1.85

1.4

Max. wheel pressure

KN

190

210

255

260

335

Total power

KW

114.8

128.8

151.3

196

243.5

steel track recommended

QU80

QU100

power source

3 phase A.C 380v 50Hz

Different grab bucket is available

overhead Grab Crane


Grab Crane

Grab Crane,Heavy Duty Hydraulic Grab Crane,Grab Bucket Overhead bridge Crane,cranes Grab

Jiangxi Mide Industrial Co., Ltd. , https://www.midecrane.com

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