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Centrifugal pump maintenance and repair: mechanical seal replacement, axle inspection and output curve testing

Technical analysis: Centrifugal pump maintenance: mechanical seal replacement, impeller inspection, and performance curv

Підтримка та ремонт центрифігального насоса: заміна механічного сальника, перевірка вісі та тестування кривої виробничої потужності - UNITEC-D Industrial MRO
Цей підручник надає конкретні інструкції для виконання заміни механічного сальника, перевірки вісі та тестування кривої виробничої потужності. Виконано у форматі практичного гідівника для виконання ро

1. Content and purpose

This manual is intended for technicians and maintenance managers who maintain and repair centrifugal pumps in industrial installations. The purpose of this manual is to provide specific instructions for performing mechanical oil seal replacement, axle inspection, and output power curve testing. The textbook is made in the format of a practical guide for performing work on site.

2. Safety and precautions

Important: Before starting any work, turn off the electrical power and mechanical power, install the locking and marking seal, and then perform an electrical and mechanical shutdown.
Important: Use personal protective equipment (protective gloves, eyes, head protection). If chemical fluids are used, use additional protective measures.
Important: When working with liquid or high pressure, ensure that all components are hermetically sealed. Use shutdown and lockout to avoid accidents.

3. Necessary tools and materials

Tool Specification Quantity
Wrench with nuts 12–30 mm 2
Key with pins 12–30 mm 2
Torque head 10–25 Nm 1
Multimeter 0–500 V 1
Laser for measurement 0.01 mm 1
Means for cleaning Dry and wet cloth 1
Axle pads 0.1–0.2 mm 5
Lubricating mastic Specialized for pumps 1

4. Purposeful inspection

Item Verification Acceptance/rejection criteria Notes
Electric power supply Off The shutdown is confirmed Confirm blocking and marking
Mechanical energy Off The shutdown is confirmed Confirm blocking and marking
Pump Immobile The shutdown is confirmed Check for no movement
Personal protective equipment Prepared Protective gloves, eyes, head Use at all stages
Cleansing done Absence of dust and liquids Use a dry and damp cloth

5. Sequence of actions

  1. Unscrew the output axle nuts
    • Use a 20-25 Nm wrench to unscrew the output axle nuts.
    • Check that the axle is not detached.
    • Error: Do not use excessive force, which can damage the sleeve.
  2. Remove the old mechanical seal
    • Use a pin wrench to remove the old seal.
    • Check if it is not left in the nest.
    • Error: fluid may leak when removing the oil seal. Use protective equipment.
  3. Preparation for installing a new oil seal
    • Install the new mechanical oil seal in the socket.
    • Check if it is correctly installed.
    • Error: Failure to install correctly may damage the sleeve.
  4. Installing the bushing
    • Use a torque head to fix the bushing to 25 Nm.
    • Check if the sleeve has not slipped.
    • Error: Using the wrong force can cause the sleeve to deform.
  5. Installing the axle
    • Install the axle in the pads using the laser to measure.
    • Check if the axis does not deviate.
    • Bug: Incorrect axle setup can lead to knocking out.
  6. Lubrication
    • Use lubricating mastic on the axle.
    • Check that the axis does not move.
    • Error: Lack of lubrication can cause overheating.
  7. Reinstallation
    • Use a wrench to install the output axle nuts.
    • Check that the axle is not detached.
    • Error: Using the wrong force can damage the sleeve.
  8. Testing
    • Use a multimeter to test the electrical supply.
    • Check if all elements are working.
    • Error: Using the wrong power supply can cause malfunction.

6. Inspection after completion of work

Test Expected result Actual result Pass/Fail
Electric power supply Off Off Pas
Mechanical energy Off Off Pas
Pump operation Stable Stable Pas
Fluid leakage Absent Absent Pas
No noise Absent Absent Pas

7. Issue tracking

Symptom Reasons Correction
Fluid leakage Incorrect installation of the oil seal Check the oil seal installation
Lack of electrical power Power off Check the power supply
Lack of mechanical energy Turning off mechanical energy Check the mechanical energy
Unstable operation of the pump Incorrect axle installation Check the axle setup
noise Improper lubrication Check the lubrication

8. Recommended maintenance schedule

Task Frequency Estimated time Skill level
Replacing the mechanical oil seal Annually 2-3 hours Average
Checking the axis Annually 1–2 hours Average
Testing the production capacity curve Annually 2-3 hours Average
Cleansing monthly 30–60 minutes Primary
Lubrication monthly 30–60 minutes Primary

9. Links to spare parts

Part description Typical specification UNITEC-D category
Mechanical stuffing box Length 150 mm, diameter 50 mm 12345
Lining for axle Thickness 0.1–0.2 mm 12346
Lubricating mastic Specialized for pumps 12347
Nuts for the output axle Material: stainless steel 12348
Screws for installing the stuffing box Material: stainless steel 12349

For spare parts visit: https://www.unitecd.com/e-catalog/

10. Links

This textbook meets the following standards:

  • DSTU 2503-99: Requirements for maintenance of industrial equipment
  • EN 733: Standards for pumps
  • ISO 9001: Quality management system
  • CE: Protection of electrical equipment
  • UkrSEPRO: State examination of electrical equipment

In addition, see the technical documents of the manufacturer and instructions for the pumps.

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