(s&g) - techav

SEALS & GASKETS (S&G)

Facilitator Guide

TABLE OF CONTENT INTRODUCTION PAGE 1 PROGRAMME MATERIAL PAGE 2 PROCEDURE PAGE 3 MODEL ANSWERS S&G-1: ROTARY SHAFT OIL SEALS TASK NO. 1 PAGE 5 TASK NO. 2 PAGE 6 TASK NO. 3 PAGE 7 TASK NO. 4 PAGE 9 TASK NO. 5 PAGE 10 CRITERION TEST PAGE 11 S&G-2: STATIC SEALS TASK NO. 1 PAGE 14 TASK NO. 2 PAGE 16 TASK NO. 3 PAGE 17 CRITERION TEST PAGE 18 S&G-3: GLAND PACKINGS TASK NO. 1 PAGE 21 TASK NO. 2 PAGE 22 CRITERION TEST PAGE 24 S&G-4: MECHANICAL SEALS TASK NO. 1 PAGE 26 TASK NO. 2 PAGE 27 TASK NO. 3 PAGE 28 TASK NO. 4 PAGE 29 CRITERION TEST PAGE 30

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INTRODUCTION This training package has been designed to offer "grass roots" level training to apprentices, operators, maintenance workers and the like in the subject of sealing. In an effort to keep the subject matter relatively simple but as broad as possible we have, wherever possible, related to equipment and machinery that is readily available and common to most industries. It is our belief that many breakdowns could be avoided if the maintenance personnel had a good basic knowledge of the principles of sealing plus the ability to apply correct maintenance techniques on the job. We hope that this series will enhance your training efforts and provide your learners with an interesting yet practical method of learning. Tech AV products are produced by Natal DVD Productions (Pty) Ltd. Special recognition however must be noted to the following organisations for their valued assistance in producing this package: John Crane (Pty) Ltd Republic Fluid Seals Payen Gaskets.


CONTENT OF PROGRAMME MATERIAL

VIDEO PROGRAMMES S&G (1) - Deals with rotary shaft seals. S&G (2) - Deals with static seals. S&G (3) - Deals with gland / compression packing. S&G (4) - Deals with mechanical seals. LEARNER WORKBOOKS One workbook is supplied with the package. You may produce photocopies for purposes of handouts to registered employees / learners. Alternatively you can obtain extra copies by ordering (P.O.R.) via: Natal DVD Productions (Pty) Ltd POBox 1235 Wandsbeck 3631 Please note that learner workbooks are an integral part of the learners learning resources. Much information is provided over and above that which is demonstrated or described in each video. The workbook also serves to provide the means whereby "Self Instruction" training may be conducted - this is deemed essential for true Competency Based programmes. FACILITATOR / COURSE CONTROLLER GUIDE This is designed as an aid to Facilitators providing overview information(regarding subject matter), model test answers and criterion checklists.


PROCEDURE FOR OPERATING THIS COURSE

IMPORTANT NOTE This training course / method is designed to be used as a training aid and in no way does it replace an experienced Facilitator, Tutor, or Course Controller. The material can be used as a "stand alone" training module, or incorporated into your existing courses. GENERAL PROCEDURE

o Each learner is provided with a copy of the workbook which is, ideally, retained for future reference.

o Learners follow the procedural instructions as dictated by the workbook. o Video material is to be requested by the learner and supplied on a loan basis - to be

returned to the Course Controller -upon completion of that segment. o Workbook exercises are completed by answering questions, as given after each task. o Practical exercises are completed in a training workshop or on the job.

NOTE: No hardware, tools or equipment is supplied with this package. o Learners request to perform the CRITERION TEST when he / she feels confident

about doing it.


PROGRAMME ONE (S&G-1)

ROTARY SHAFT OIL SEALS

TRAINING OBJECTIVE After completing this section of the package learners will be able to select and replace (rubber lipped) oil seals into typical equipment using conventional tools and procedures. TRAINING AIDS REQUIRED

o Normal hand tools applicable to fitter / mechanic. o Workshop equipment such as gear pullers, hydraulic press or an arbour press,

suitable dollies for oil seal installation, and shaft protection sleeves. SUMMARY OF SUBJECT MATTER

o An overview of oil seals. o Identification of seal types and applications. o Seal selection principles. o Seal removal and replacement techniques. o Common causes of seal failures.

ESTIMATED LEARNING TIME Approximately 1 day. TEST Practical exercise involving all the described procedures and principles provided via the learning resources.


MODEL ANSWERS

S&G 1: TASK NO. 1

QUESTIONS YES NO

1. What other name is an oil seal commonly known as? Rotary shaft oil seal.

2. What are the two basic oil seal types? i) Bonded. ii) Assembled.

3. What design of seal would you select to suit the following conditions? i) Light load, oil lubricant, high speed clean environment:

Single lip seal. ii) Medium to light dust in air, light loads, oil as lubricant:

Double lip seal. iii) Heavy environmental contamination, including mud:

Duplex seal. iv) Automotive engine crankshaft:

Hydrodynamic seal.


S&G 1: TASK NO. 2

INSTRUCTIONS

o Practical Assessment: Mark / Check in the learner workbook. o Check trainees work against the criteria below.

ITEM CRITERIA YES NO

PRE-CLEANING Area around seal thoroughly cleaned.

SAFETY All safety requirements observed.

REMOVING Seal removed using approved method. Correct tools / equipment utilised.

CLEAN-UP Openings protected against “fall-in” debris.

INSPECT All damage, wear etc. reported / noted.

SHAFT Shaft (seal runner) cleaned up / polished.

WORK ASSESSED BY __________________________ CAPACITY _______________________

CRITERION OBTAINED: YES NO


S&G 1: TASK NO. 3

QUESTIONS YES NO

1. What are the four factors that determine the selection of an oil seal? i) Size. ii) Shaft speed. iii) Pressure against seal. iv) Operating temperature.

2. What does the following seal part number indicate (in terms of the size)? SEAL NO: SM528010 52 = Shaft diameter. 80 = Housing / seal bore diameter. 10 = Seal height.

3. What information must you give a seal supplier if you need an oil seal but do not have a sample to compare from? i) Shaft size. ii) Housing bore diameter. iii) Depth from cover face to shoulder.

4. What is the maximum pressure that a standard oil seal can work in? 0.5 bars.

5. What problems will result if pressure goes above "normal"? Seal lip may be blown out.

6. What should you do before attempting to fit a "back-up ring"? Seek the advice of experts.

7. What effect does an excess of temperature have on an oil seal? Causes seal element (lip) to become hard and brittle.


8. What are the 4 popular materials used to manufacture oil seals? (Le. Sealing Element Material) i) Nitrile. ii) Polyacrylic. iii) Silicone. iv) Viton (or Fluorocarbon).

9. Which of the four materials mentioned is the most common? Nitrile.

10. Which seal material is the most expensive? Fluorocarbon.

11. Which oil would be suitable for use on the crankshaft of an automobile engine? Silicone.

12. Which seal material feels "heavy" when compared to a seal of similar size and colour? Fluorocarbon.

13. Which seal is the most likely to be used in a chemical industry? Fluorocarbon.


S&G 1: TASK NO. 4

INSTRUCTIONS

o Practical Assessment: Mark / Check in the learner workbook. o Check learners work against the criteria below.


PREPARE Work piece is extremely clean. Tools and equipment clean.

INSTALL

Seal entered squarely into housing. Fitting sleeve used if required. Correct oil applied to lip and sleeve. Sealant used on metal seal (if applicable).

CHECKS

Seal is not damaged (after fitting). Seal edge (face) is flush to housing, or Seal is fully seated in housing bore. Seal fitted in the right way round.




S&G 1: TASK NO. 5

QUESTIONS YES NO

1. List 5 actions that are considered to be “poor fitting techniques: a) Using sharp / pointed tools. b) Using correct dollies. c) Twisting seal (i.e. bending seal). d) Cooking seal. e) Not cleaning parts properly.

2. List 8 typical conditions that can cause seal failure (leakage). a) Wrong selection of type / design / material. b) Cracked bore / housing. c) Highspots or burr on shaft or housing. d) Block breather / vent. e) Excessive temperature. f) Worn mechanical parts. g) Distorted shaft. h) Wrong oil grade / level.


CRITERION TEST

ROTARY SHAFT SEALS GENERAL The criterion test is an assessment of what the learner has learnt and what he / she is able to do! Now that instruction is completed for rotary shaft seals. INSTRUCTIONS

o Provide learner with a work piece (i.e. a piece of machinery or a machine) to work on.

o Learner must renew the oil seal(s). ASSESSMENT Learner will be assessed on how well the job has been done. The “criterion” is that the seal or seals that that the learner replaced is fitted correctly and that leakage does not occur as a result. SUGGESTED WORK / EXERCISES:

o Old internal combustion engine. o Reduction gearboxes.


CRITERION TEST NO. 1

ROTARY SHAFT OIL SEALS CHECK LIST / REPORT

LEARNER: _____________________________ DATE OF TEST: ________________________ COMPANY: __________________________ ATTEMPT NO: __________________________

RENEWAL OF OIL SEAL



REMARKS: __________________________________________________________________ ___________________________________________________________________________

NO. CRITERION / DESCRIPTION YES NO

1. Work piece was cleaned prior to dismantling.

2. Only the necessary components removed for access.

3. Seal removed correctly (i.e. no damage to machine).

4. Housing and shaft cleaned and inspected.

5. Correct replacement seal selected.

6. Correct dolly (pressuring tool) selected.

7. Seal installed correctly / used correct procedure.

8. Seal properly seated and flush or concentric.

9. Sealant used (where applicable).

10. Lubricant levels replenished.

11. Components re-installed correctly (e.g. pulley).

TOTAL


S&G-2: STATIC SEALS TRAINING OBJECTIVE After completing this section of the programme learners will be able to select and replace typical static seals as well as to make paper / board based gaskets using conventional hand tools. TRAINING AIDS REQUIRED

o Normal hand tools applicable to fitter / mechanic. o Prefabricated gaskets. o O-rings. o Assorted sealants.

SUMMARY OF SUBJECT MATTER

o An overview of static seals. o Replacing of static seals. o Manufacture of paper / board based gaskets.

ESTIMATED LEARNING TIME Approximately 4 hours. TEST Practical exercise involving the replacement and manufacture of a gasket.


MODEL ANSWERS

S&G 2: TASK NO. 1

QUESTIONS YES NO

1. What 4 classifications are there, concerning static seals? a) Non-metallic gaskets. b) Metallic gaskets. c) Static O-rings. d) Sealants.

2. Why must the material for the gaskets be of a material that is softer than the joint/flange? In order that the small gaps in metal surfaces are filled (i.e. plugged) or so that the gasket is able to “conform” to the joint.

3. What materials are used, typically, to produce gaskets that do not have any metal in them? a) Paper (treated). b) Board (treated). c) Asbestos. d) Graphite. e) Cork. f) Rubber. g) Plastic.

4. What materials are commonly used in gaskets that do contain metal? a) Copper. b) Leak. c) Zinc. d) Mild steel.

5. What gasket material is commonly used when the joint is subject to high temperature? Asbestos.

6. What type of (classification) gasket is commonly used to seal high pressure? Metallic.


7. What type of seal would be used in a small confined space? O-ring.

8. What two categories of liquid "sealants" are there? a) Hardening. b) Non-hardening.


S&G 2: TASK 2

INSTRUCTIONS



PREPARE Work / machine isolated safely. Area around the seal is cleaned.

GASKET Correct new gasket obtained.

CLEANING All surfaces (facings) thoroughly cleaned. Openings plugged as necessary.

INSPECTION Any faults, damage of surfaces noted. Studs or blind holes free of debris.

FITTING

Gasket properly positioned. Correct sealant used (as necessary). Anti-seize used on fasteners. Component tightened as per specification.

OTHER As necessary – fluids drained. As necessary – fluids replenished.




S&G 2: TASK NO. 3

INSTRUCTIONS



PREPERATION Work / material isolated. Area around gasket is properly cleaned.

MATERIAL Correct gasket material selected.

MAKING GASKET

Size of gasket area cut off (minimum wastage). Shape of gasket marked off (any method). All bolt / stud holes neatly and accurately cut. All cutting neatly performed.

FITTING Gaskets fit neatly to machine / work.




CRITERION TEST

STATIC SEALS

GENERAL The Criterion Test is an assessment of what you have learnt and are able to do! Now that instruction is completed for Static Seals. INSTRUCTIONS

o Ask your Facilitator / Course Controller for suitable work piece / machine to work on. o Replace (i.e. renew) all the gaskets on the machine and make at least one gasket.

ASSESSMENT You will be assessed on how well you do the job. The Criterion is that the gaskets, when replaced, fit correctly and do not leak as a result of your workmanship. SUGGESTED WORK / EXERCISE:

o Old internal combustion engine. o Reduction gearboxes. o Pump or compressor. o Industrial pipework.



STATIC SEALS CHECKLIST / REPORT

LEARNER: ______________________________ DATE OF TEST: _______________________ COMPANY: _____________________________ ATTEMPT NO.: _______________________

REPLACING STATIC SEALS


1. Work piece properly cleaned before dismantling.

2. Work piece dismantled with surface damage.

3. Sealing surfaces properly cleaned and inspected.

4. Correct replacement gasket selected.

5. Sealant, if required, applied correctly.

6. One gasket manufactured.

7. Gasket fits properly (i.e. aligns to all features).

8. Fluids topped up.

9. Fasteners correctly secured.

WORK ASSESSED BY __________________________ CAPACITY _____________________


REMARKS: ________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________

TOTAL


S&G-3: GLAND PACKINGS

TRAINING OBJECTIVE After completing this section of the package learners will be able to repack a typical pump or valve using conventional compression packing. TRAINING AIDS REQUIRED

o Normal hand tools applicable to plant fitters. o Assorted packing material. o Centrifugal pump and / or gate and globe valves. o Packing extractor tools. o Shaft or mandrel. o Split collar packing installer or tamping sticks.


o An overview of packing’s. o Maintenance of gland packing’s.

ESTIMATED LEARNING TIME Approximately four hours. TEST Practical exercise involving the replacements of a gland packing in situ.


MODEL ANSWERS

S&G-3 TASK NO. 1

QUESTIONS YES NO

1. What is another common term for a gland packing’s? “Compression” packing.

2. What are the main reasons for allowing “leakage” past a gland packing? a) Lubrication. b) Heat dissipation.

3. What result will the overtightening of a gland give? Overheating and dry-running.

4. Achieving desired flow rates (leakage) is effected by two factors – what are they? a) Selection of correct material. b) Good maintenance.

5. What is dry-running lubricant required for? To assist in lubricating during start up periods.

6. The selection of any packing material depends on several factors, name five. a) The product (in system). b) Shaft speed. c) Shaft diameter. d) Pressure in system. e) Temperature (heat) in system.

7. If you’re not sure which packing to use, what should you do? a) Find out via your supervisor. b) Find out via your supplier. c) Find out via your original equipment manufacturers.


S&G-3: TASK NO. 2 INSTRUCTIONS

o Practical Assessment: Mark / Check in the learner workbook. o Provide learner with a suitable work piece (e.g. pump or valve) that requires renewal

of gland packings. o Learner must replace the gland packings using the procedures demonstrated as per

resource notes and video. o Check learners work against the criteria below. o Learners must answer questions following the Criteria check-list.


1. PREPERATION OF WORK

Pressure relieved from stuffing box. Old rings removed using extractor. All materials / debris cleaned out of stuffing box. Shaft / bore concentricity checked. Shaft run-out checked. Shaft surfaces checked & cleaned up. Gland follower checked / clearances. Neck bush (if applicable) checked / clearance. Depth of stuffing box measured.

2. PACKING RINGS

Mandrel-shaft used / correct diameter. Packing wrapped onto mandrel tightly. Markings / parallel lines scribed / drawn. Cuts made across diagonal.

3. FITTING

First packing checked for fit / clearances. Shaft turns freely. Packing “tamped” into stuffing box bore correctly. Subsequent rings – gaps staggered. Anti-seize compound used (where applicable).

4. RUN-IN / ADJUSTMENT

In accordance with specifications / drip-rate.


QUESTIONS YES NO

1. How tight should the gland nuts/studs be made initially after fitting new packing rings? Finger tight.

2. How long is a pump run with full leakage after the first start up? 10 minutes.

3. What amount of tightness is given on each nut when adjusting for leakage? 1/6 of a turn.

4. At what stage can you be sure that adjustments have been completed? When drip rate is a minimum specified.



GLAND PACKINGS CHECKLIST / REPORT

LEARNER: ____________________________ DATE OF TEST: _________________________ COMPANY: ___________________________ ATTEMPT NO: _________________________

REPLACING PACKINGS


1. All safety requirements adhered to.

2. Old packings removed and stuffing box clean.

3. All integrity checks performed.

4. Correct packing material selected or requested.

5. Packing rings correctly produced.

6. Rings correctly installed.

7. Pump shaft turns freely (i.e. no binding)

8. Drip rate adjusted to specified amount.

9. Pump started up correctly.

10. Temperature at gland normal after running.



REMARKS: ________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________

TOTAL


S&G-4: MECHANICAL SEALS

TRAINING OBJECTIVE After completing this section of the package learners will be able to identify and describe the principle operation of typical mechanical seals. Describe the important maintenance aspects that affect successful seal operation. TRAINING AIDS REQUIRED

o Pump (centrifugal - single stage end-suction or similar). o Measuring instruments, including D.T.I., micrometres etc.


o Principles / fundamentals of mechanical seals. o Identification of seal types. o Important maintenance aspects.

ESTIMATED LEARNING TIME Approximately four hours. TEST Theoretical test question master sheet overleaf.


MODEL ANSWERS

S&G-4: TASK NO. 1

QUESTIONS YES NO

1. Mechanical seals have 3 distinct areas of sealing, name these: a) Primary sealing. b) Secondary sealing. c) Tertiary sealing.

2. What is the function of the spring(s) behind the face ring? To keep the face in contact with the seat.

3. Name the 3 basic types of secondary sealing. a) O-ring. b) Wedge ring. c) Bellows.

4. Which of the above are known as pusher type seals? a) O-ring. b) Wedge ring.

5. Which of the above seals has no wear factor against its secondary seal? Bellows.

6. What prevents a leakage past or around the seat / housing? The tertiary seal.

7. Give 3 examples of sealing methods for your answer in question 6. a) O-ring. b) Cup. c) Clamped / or rectangular.


S&G-4: TASK NO. 2

QUESTIONS YES NO

1. What is the (main) purpose of a drive unit? To provide the means of transferring power / rotation to the face.

2. What are the four major elements of a mechanical seal? a) Primary seal unit. b) Secondary seal. c) Tertiary seal. d) Drive unit.

3. What are the 3 main seal types? a) O-ring seals. b) Wedge seals. c) Bellows seals.

4. What does the term pusher seal mean? The secondary seal is activated by a pushing force.


S&G-4: TASK NO. 3

QUESTIONS YES NO

1. Why is primary seal cooling necessary? To prevent excessive heat build-up / seal face damage.

2. Why must a seal be handled only in clean conditions? To prevent contamination / damage to facing surfaces.

3. How is a primary seal commonly lubricated and cooled? By passing recirculated product / fluid across it.

4. What is required, in the recirculation system, when product temperature is less than 25 degrees below its boiling point? A recirculating system that is cooled via air fins or a heat exchanger.

5. A separate cooling system delivers cool fluid, where? Separate systems circulate cool fluid behind the stationary seat.

6. What is important in respect of operating and maintaining equipment / plant? To heed the recommendation, company rules etc.


S&G-4: TASK NO. 4

QUESTIONS YES NO

1. List the main “integrity” checks and measurements on a pump in order that a mechanical seal can be installed.

i) Shaft straightness. ii) Rotational balance. iii) Shaft run-out. iv) Bearing clearances. v) Shaft ovality at secondary sealing area. vi) Concentricity at the stuffing box. vii) Seat squareness. viii) Coupling alignment.

2. What procedure should you follow when installing a seal? Follow the manufacturer’s instructions.


CRITERION TEST S&G-4

MECHANICAL SEALS LEARNER: _____________________________ DATE OF TEST: ________________________ COMPANY: ____________________________ ATTEMPT NO: ________________________ INSTRUCTIONS Answer all questions without reference to notes or video resources.

QUESTIONS YES NO

1. What are the 3 areas of sealing known as (i.e. concerning a typical mechanical seal)? a) _______________________________________________ b) _______________________________________________ c) _______________________________________________

2. What does the term “pusher type seal” refer to? ANS: _________________________________________________ _____________________________________________________ _____________________________________________________

3. Why is it important to handle mechanical seals carefully and keep them clean? ANS: _________________________________________________ _____________________________________________________ _____________________________________________________

4. What is the “fluid interface”? ANS: _________________________________________________ _____________________________________________________

5. Why is interface lubrication and cooling so important? ANS: _________________________________________________ _____________________________________________________


6. List the “integrity” checks that should be made on a centrifugal pump prior to and after installing a mechanical seal. a) _______________________________________________ b) _______________________________________________ c) _______________________________________________ d) _______________________________________________ e) _______________________________________________ f) _______________________________________________ g) _______________________________________________ h) _______________________________________________

7. When actually installing a mechanical seal, what is your most important aid? ANS: _________________________________________________ _____________________________________________________



REMARKS: ________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________

END OF PROGRAMME.

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