FIG. 6.1 SEPARATOR FILTER ELEMENT

FAULT FINDING

FIG. 6.1 SEPARATOR FILTER ELEMENT

1.1 Description

Primary separation of oil from the air/oil mixture takes place in the separator vessel which is positioned between the air-end and aftercooler.

The separator comprises a steel pressure vessel with a welded cover.

The cover carries the pipe connections for the air and oil pipework and a safety relief valve. An oil filler pipe and oil level sightglass assembly are fitted to the wall of the separator vessel.

The separator vessel operates in conjunction with a separator filter element (Fig. 5.3) where final separation takes place. The separator element is located on the manifold block and is fabricated from layers of micro fine glass fibre, supported by tubes and protected externally by a perforated steel sheath. A scavenge pipe, located on the underside of the manifold block, passes through the centre of the element which screws into position against a machined face.

1.2 Operation

The air/oil mixture passes from the air-end

discharge pipe into the primary oil separator vessel where initial separation takes place by centrifugal force. Most of the oil is separated at this stage and drops to the bottom of the vessel.

The remaining air/oil mixture then passes through two separator filter elements where final separation takes place. The separator element functions with the principle of coalescence. The micro glass fibre layers separate the oil droplets which collect in the bottom of the filter and are scavenged back into the air-end through a small diameter pipe

The filtered air then passes from the oil separation element by way of the minimum pressure/ non-return valve. Provided the air pressure at this stage is above 3.5 to 4·0 bar the air passes through the aftercooler where it is cooled before passing to the delivery outlet.

If the air pressure in the primary oil separator falls below 3.5 to 4·0 bar the minimum pressure valve will close. The valve also incorporates a non-return valve which operates to prevent delivery air

passing back into the separator when the compressor is running off-load.

Oil from the bottom of the primary oil separator flows under pressure to the oil cooler and during normal running the oil passes through the cooler to maintain the correct temperature. A thermostatic bypass valve is installed in the inlet manifold of the oil cooler.

FIG. 6.3 RECLAIMER (L120SR) 2. RECLAIMER (475SR, L75SR, L120SR)

1. Pressure Vessel 2. Joint

3. Cover

4. Scavenge Pipe

5. Minimum Pressure Valve 6. Air Outlet

7. Pressure Relief Valve 8. Filter Element

9. Oil Outlet 10. Air/Oil Inlet 11. Oil Reservoir 12. Drain Connection 13. Oil Level Sight Tube 14. Oil Filler

15. Excess Pressure Switch

FIG. 6.2 RECLAIMER (475SR, L75SR)

1. Pressure Vessel 2. Joint

3. Cover

4. Scavenge Pipe

5. Minimum Pressure Valve 6. Air Outlet

7. Pressure Relief Valve 8. Filter Element

9. Oil Outlet 10. Air/Oil Inlet 11. Oil Reservoir 12. Drain Connection 13. Oil Level Sight Tube 14. Oil Filler

15. Pressure Transducer 5

2.1 Description (475SR and L75SR) - fig. 6.2 Separation of oil from the oil/air mixture takes place in the reclaimer which is positioned between the air-end and air/oil cooler.

The reclaimer comprises a steel pressure vessel (1) with a removable cover (3). A filter element (8) is contained within the pressure vessel.

The filter element is fabricated from layers of micro fine glass fibre, supported by tubes and protected externally by a perforated steel sheath wrapped in a pre-filter element. The element is suspended by a flange from the top of the pressure vessel. The assembly is sealed with a joint (2) and secured in position by the cover.

The cover carries the minimum pressure valve (5), scavenge oil pipe (4) and air connections for the regulation system. A drain connection (12), oil filler (14), pressure relief valve (7), oil level sight glass (13) and excess pressure switch (15) are fitted to the wall of the pressure vessel. The lower portion of the pressure vessel forms an oil reservoir (11).

2.2 Description (L120SR) - fig. 6.3

Separation of oil from the oil/air mixture takes place in the reclaimer which is positioned between the air-end and air/oil cooler.

The reclaimer comprises a steel pressure vessel (1) with a removable cover (3). A filter element (8) is contained within the pressure vessel.

The cover carries the minimum pressure valve (5), scavenge oil pipe (4) and air connections for the regulation system. A drain connection (12), oil filler (14), pressure relief valve (7), oil level sight glass (13) and pressure transducer (5) are fitted to the wall of the pressure vessel. The lower portion of the pressure vessel forms an oil reservoir (11).

2.3 Operation

The air/oil mixture passes from the discharge port of the air-end into the reclaimer inlet (10).

Centrifugal primary separation of the oil occurs and most of the oil droplets fall into the oil reservoir.

The differential pressure between the inside and the outside of the element causes the remaining oil droplets to pass through the two stages of the reclaimer element where final separation takes place.

The reclaimer element functions on the principle of coalescence. The micro glass fibre layers separate the small oil droplets from the compressed air/oil mixture to form larger droplets which drain down to collect inside the bottom of the element. The accumulation of oil in the element is returned to the air end through the scavenge system.

7. Guide Pin 8. Spring 9. ‘O’ Ring Seal 10. Piston 11. Spring 12. Valve Body 1. Locknut

2. Washer 3. Retainer 4. ‘O’ Ring 5. Valve Head 6. ‘O’ Ring Seal

FIG. 6.4 MINIMUM PRESSURE VALVE (345SR, L45SR) 3. MINIMUM PRESSURE VALVE (345SR, L45SR)

3.1 Description

The minimum pressure valve fits inside the manifold block and performs the following main functions:

1. It ensures a rapid pressure build-up in the reclaimer during initial start-up. The minimum pressure valve is held closed until the

pressure in the reclaimer reaches 3.5 to 4 bar.

2. It prevents high velocity, low pressure air carrying over excessive amounts of oil into the delivery air pipe during start-up.

3. The minimum pressure valve also

incorporates a non-return valve. This prevents pressurised air in the user’s pipework passing back into the reclaimer when the compressor unit stops or runs off-load.

The minimum pressure valve consists of a valve body (12), valve assembly, and piston (10).

The valve assembly comprises a guide pin (7), valve head (5), retainer (3) and two ‘O’ ring seals (4, 6) secured by a washer (2) and a locknut (1).

The guide pin houses a spring (8) and is located inside the piston.

The valve head is seated against a face machined in the manifold block. The piston moves inside the bore of the valve body and two springs (11) force the piston against the rear face of the valve assembly. An ‘O’ ring seal (9) fitted to the outside of the piston prevents any pressure leakage past the piston.

The piston and valve assembly move to control the flow of air through the valve.

1 3 4 5 6 7 8

9 10

11 12

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3.2 Operation

When the compressor starts, the minimum pressure valve is held in the closed position by the effect of a spring against the top of the piston and by the face of the piston holding the valve assembly against the seat. The valve remains closed until the pressure in the separator vessel reaches a set minimum pressure (3.5 to 4 bar). When the pressure in the separator vessel overcomes the force exerted by the two springs, the valve assembly and piston move up allowing full air flow past the open valve, through the outlet port and into the main delivery pipe to the aftercooler.

When the compressor off-loads the flow of air ceases between the separator vessel and the user’s pipework. Pressure in the compressor system acts to hold the minimum pressure valve piston in the raised position against the effect of the spring and at the same time the valve spring closes the non-return valve onto its seat.

When the compressor reverts to on-load running, the valve assembly will stay closed against the seat until the pressure in the separator vessel exceeds the pressure in the user’s pipework. The plunger will not return to close the outlet until the pressure in the user’s pipework falls below the force of the springs.

4. MINIMUM PRESSURE VALVE (475SR, L75SR)

1. Piston Housing 9. Retainer 2. Outer Piston Spring 10. 'O' Ring 3. Inner Piston Spring 11. Body

4. Piston 12. Guide Pin

5. Valve Head 13. 'O' Ring

6. 'O' Ring 14. Spring

7. Washer 15. 'O' Ring

8. Locknut

FIG. 6.5 MINIMUM PRESSURE VALVE (475SR, L75SR)

4.1 Description

The minimum pressure valve is mounted on the reclaimer cover and performs the following functions:

1. It ensures a rapid pressure build-up in the reclaimer during initial start-up. The minimum pressure valve is held closed until the pressure in the reclaimer reaches approximately 4 bar.

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2. It prevents high velocity, low pressure air carrying over excessive amounts of oil into the delivery air pipe during start-up.

3. It acts as a non-return valve preventing pressurised air in the user’s pipework passing back into the reclaimer when the compressor unit stops or runs off-load.

The minimum pressure valve consists of a valve body (11), a valve assembly and a piston housing (1). The valve assembly comprises a piston (4) and 'O' ring (13), guide pin (12) and valve spring (14), a valve head (5) with ‘O’ ring seal (10) and retainer (9) secured by a washer (7) and locknut (8). An 'O' ring (6) provides a seal between the valve head and guide pin. The guide pin and spring are located inside the piston. The valve head and ‘O’ ring seal operates against a seat formed in the valve body (11). The piston moves inside the bore of the piston housing and two piston springs (2,3) force the piston against the rear face of the valve assembly.

The piston and valve assembly move to control the flow of air through the valve.

A tapped hole in the base of the valve body provides a connection to the differential pressure indicator.

4.2 Operation

When the compressor starts, the minimum pressure valve is held in the closed position by the piston springs. The valve remains closed until the pressure in the reclaimer reaches a set minimum pressure (4 bar). When the pressure in the reclaimer overcomes the force exerted by the two piston springs, the valve assembly and piston move up allowing full air flow past the open valve, through the outlet port and into the main delivery pipe to the aftercooler.

When the compressor comes off-load the flow of air ceases between the reclaimer and the user’s pipework. Downstream pressure in the system acts to hold the minimum pressure valve piston (4) in the raised position against the effect of the piston springs and at the same time the valve spring (14) closes the non-return valve head (5) on to its seat.

The piston will not return to close the outlet until the pressure in the user’s pipework falls below the set pressure of 4 bar.

When the compressor reverts to on-load running, the valve will stay closed against the seat until

5. MINIMUM PRESSURE/NON RETURN VALVE (L120SR)

5.1 Description

The minimum pressure valve is mounted on the reclaimer cover and performs the following functions:

1. It ensures a rapid pressure build-up in the reclaimer during initial start-up. The minimum pressure valve is held closed until the pressure in the reclaimer reaches approximately 4 bar.

2. It prevents high velocity, low pressure air carrying over excessive amounts of oil into the delivery air pipe during start-up.

3. It acts as a non-return valve preventing pressurised air in the user’s pipework passing back into the reclaimer when the compressor unit stops or runs off-load.

The minimum pressure valve consists of a valve body (8), a valve assembly and a piston housing (1). The valve assembly comprises piston (4), 'O' ring (6) and valve head (5). The valve head stem is located inside the piston and has a moulded seal which operates against a seat formed in the valve body (8). The piston moves inside the bore of the piston housing. The piston moves inside the bore of the piston housing and two piston springs (2,3) force the piston against the rear face of the valve assembly. The piston and valve assembly move to control the flow of air through the valve.

5.2 Operation

When the compressor comes off-load the flow of air ceases between the reclaimer and the user’s pipework. Downstream pressure in the system acts to hold the minimum pressure valve piston (4) in the raised position against the effect of the piston

moves out from the piston and the valve head closes onto its seat to act as a non-return valve.

The piston will not return to close the outlet until the pressure in the user’s pipework falls below the set pressure of 4 bar.

When the compressor reverts to on-load running, the valve will stay closed against the seat until reclaimer pressure again exceeds 4 bar.

6. DIFFERENTIAL PRESSURE INDICATOR

In document LSR Cyclon Repair Manual (Page 81-87)