13 Basic Purifier questions that Every Junior Must Read.

I am Sure At least one of these questions may come handy While you are in the purifier room or in any MMD.

Purifier Class 4 MMD Questions
A Closer Look at Frequently Asked Questions on Purifier

13. What are the purifier safeties?

  • Brake
  • Emergency stop
  • Vibration monitor
  • HT alarm
  • Metal sheeting on I/O pipes
  • Overload trip
  • Lower backpressure alarm

12. What is the importance of measuring the vertical height?

  • To avoid rubbing of pairing disk on pairing chamber

11. Which Component takes the vertical vibration and which component takes the horizontal vibration?

  • Spring inside bottom bearing case takes the vertical vibration
  • Buffer springs around neck bearings - they take radial vibration

10. What will be your action if you see the purifier vibrating when it is being stopped?

  • Apply the brakes immediately.

9. What is alcap purifier?

  • Its a centrifugal seperator no gravity disk or sealing water. But has a water outlet which stays most of the time closed clean oil is continuously being monitored if water comes in, It is desludged.

8. Reasons for the vibration of the purifier?

  • Sludge accumulation on one side during desludging or Sludge on one side got sticky
  • Bearing wear
  • Loose foundation Bolts
  • At the time of starting, Bigger gear Drives the Smaller gear and at the time of stopping, The reversal of action takes place ie, the smaller gear drives the bigger gear which is not suitable worm and gear arrangement and vibration may occur. and further, the gear arrangement may break due to stress.
  • Bearing Failure
  • Uneven wear of friction clutch
  • Motor speed too low or too high

7. What happens if the E/O has given the purifier motor connection the wrong way?

  • Friction Clutch won't be able to maintain the correct speed.
  • Locknut holding bowl onto spindle will come loose which is otherwise self-tightening
  • Pairing Disk (A.K.A) Cannot develop Enough Head.

6. What are the Purifier Overflow reasons?

  • Low RPM and Wrong Direction
  • Leaking 3-way valve
  • Excessive Back Pressure or service tank valve is in closed condition
  • If bowl opening water is leaky or opened by mistake
  • The Teflon sealing ring is not sealing properly
  • Bowl is not properly closed
  • Sealing water is insufficient
  • Excessive sludge deposit inside the bowl
  • No Operating water (A.K.A bowl closing water)or leaky
  • Incorrect Gravity Disk size
  • Operating water Filter Chocked
  •  Bowl is not properly Sealed
  • Feed oil Temperature High or low
  • High Throughput
  • Worn out Orings near the Plug or Nozzle
  • The orifice plate is installed in the wrong way

5. What Should be your action if the Purifier is overflowing?

  • Check the operating water filter- It should not be Dirty
  • Check Oil Feed Temperature
  • Check The Feed Rate
  • Check RPM
  • Check All valves position closing and opening condition
  • Check For position Of 3 way Valve
  • Check Gravity Disk

4. How separation is done in a purifier?

  • Thin strata separation
Flow is laminar maximum at center, Minimum near boundaries,Zero at Boundary

Centrifugal Force on Heavier particles is more than upward force at the boundaries.

Related read: Purifier Principle 

3. How will you come to know if the purifier disk stacks have lost its compression?

  • While assembling, Locknut will Align with O - O Mark Without any Effort, By tightening, it crosses too much

 2. How to know the friction pad of the purifier is worn out?

  • Longer time to Build up RPM

1. Why purifier RPM is not attaining its rated speed?
  • Break Pad is not in Normal Position
  • Too much Sludge accumulation
  • Single Phasing
  • Bearing problem
  • Sump Oil Level Is Too high
  • Shafts are out of alignment
  • Bowl is Not in the correct position

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Post a Comment


  1. why during desludge, purifier ampere is increased?

    1. During desludging bowl weight is coming onto the shaft. Thats why motor has more load hence more amperage.


Feel free to ask any doubt.