Svendborg Conveyor Brake Maintenance

Transcription

1 CLIENT LOGO OPF MAINTENANCE WORK INSTRUCTION CLIENT DOC NUMBER Scope PREPARATION AND INFORMATION The Svendborg Brake is designed to transfer a braking torque from the calliper to a brake disc in order to stop the rotation of the brake disc. During the initial manufacture all pressure control valves, flow control valves, pump regulators and signaling devices, such as pressure switches are adjusted and adjusted again during the commissioning of the brake components to the conveyor drive. The brake settings must be monitored continuously during operation and then subsequently, at reasonable intervals. Regular maintenance inspections and attention to detail are required to detect faults in early stages of operation and so prevent more serious malfunctions. Inspections should identify and Notifications be raised for: External leaks, Unusual noises from pumps, motors, couplings etc., Dirt build-up, Proper function of equipment including Damage, especially to hoses and pipes, instrumentation. Before commencing this work complete a 5 STEP every time to check that no abnormal conditions exist and complete a JHA if prompted by the 5 STEP. Always wear the correct PPE NOTE: SPECIAL TOOLING REQUIRED Always assume the equipment is LIVE until positively isolated, locked and tagged. Fitter s Tool Kit and tooling referenced on Page 8 of this document. Lower Chute Liners Power Pack: Custom Brakes APU Calliper: Svendborg BSFI 28 3S 1 Brake Detail Rev PREPARED BY CHECKED BY APPROVED BY Darren Fennell Pyxis Services Page 1 of 7

2 Maintenance Activities: 1. Manual Release of the Calliper 2. Filtration and Replacing the Hydraulic Filter 3. Checking / Charging the Accumulator 4. Bleeding the Brakes Brake Maintenance 5. Brake Pad Adjustment 6. Replacing the Brake Pad 7. Brake Pad Alignment 8. Bedding in of Brake Pads Note: Brush clean the brake callipers, mountings, hoses, hydraulic lines and Power Pack, so equipment is free of dust and debris before commencing maintenance. Task Description 1. Manual release of the caliper. Manual release of the caliper is by use of a hand pump fitted with a quick release coupling, matching that fitted to the power unit as follows: a. The hand pump must be filled with filtered fluid of the same type as the braking system / power unit. b. The hand pump must also have the internal relief set to a maximum of 3 Bar. c. Connect the hose to the quick release coupling on the power unit. d. Depress the override button on the directional control valve. e. Operate the hand pump and build pressure so as to apply enough pressure increase for the calliper pistons to release. Note: Care must be taken at pinch point between the brake pads and disc. Always release the oil back through the hand pump, otherwise the power unit tank will be overfilled. 2. Filtration The oil in a hydraulic system and the oil added to the hydraulic system must always be filtered. The level of cleanliness is an important factor in the lifetime of the system. When re-filling the hydraulic tank, it is recommended that the oil added to the system be filtered through an off-line filter unit with a minimum 1 micron nominal filtration. The hydraulic power unit has a built-in oil pressure filter with a standard minimum 1 micron nominal filter rating. To maintain a reliable system it is recommend that only hydraulic oil of the following classes of purity is used: NAS 1638, Class 8, or ISO 446, Class 16/13. Replacing the hydraulic fluid The power unit is supplied with a hydraulic oil tank that must be drained, cleaned and the fluid replaced at a minimum once a year, as per the following process: a. Make sure that the electric motor is not running, that no voltage is connected to the solenoid valve, (system isolated) and that the system oil pressure is drained ( Bar). b. Clean dust and dirt from the outside surface of the hydraulic unit before removing plugs or fittings. c. Remove the four bell housing / tank screws and the tank will fall away below, take care to ensure it does not drop. d. Clean the tank out with dry clean rag, ensuring that any contaminates are removed and recorded. Page 2 of 7

3 e. Refill with hydraulic fluid, ensuring the tank square section seal is in place, mounted on the tank, top entry hole. f. Start the power unit and make sure that there is no leakage. g. Check the oil level and re-fill if necessary. 3. Checking / Charging the Accumulator Note: Working on systems with accumulators must only be carried out after the pressure and fluid has been released. The diaphragm accumulator uses dry Nitrogen as the compressible medium. Accumulator Pre-charge Pressure = 13 Bar. Equipment Required A S C B O 6 mm Allen Key D P U V Charging head c/w hose Gas Accumulator Procedure: a. Connect the charging head to the nitrogen bottle via the charging hose. b. Using an Allen key, loosen the screw P in the accumulator, only enough without losing gas. c. Install the charging head onto the accumulator. d. Close valve B as shown in the accompanying diagram. e. Open the spindle valve A thus opening the screw P in the accumulator. f. Open the shut-off valve on the nitrogen bottle. Slowly release nitrogen into the accumulator, to ensure better pressure compensation and to prevent damage to the gas valve insert. g. Close the shut-off valve on the nitrogen bottle and check charging pressure on the gauge. h. Repeat this process until the required charging pressure is reached (13 bar). i. After a period of approx 5 minutes, during which time temperature compensation takes place, re-check pressure and adjust if necessary. j. When the required charging pressure is reached (13 Bar), then tighten Spindle A on the accumulator to close accumulator valve V. Release the line pressure via valve B prior to removing the charging and testing unit. k. Retighten cap screw P on the accumulator with a 6 mm Allen Key to a torque of 2 Nm. l. Check the gas valve on the accumulator for leakages by means of leak detector spray, or soapy water. m. Smear the top of the accumulator around the gas valve and the cap thread with a little light grease to stop corrosion and screw the protective cap onto the gas valve of the accumulator and tighten. Page 3 of 7

4 Brake Settings including torque and brake time Conveyor No Calliper Clamping Force (N) Accumulator Pre-charge Pressure Balance 1mm air gap Fully lifted Piston pressure Pressure switch settings Motor contacts OU1 = Hnc On/off contacts OU2 = Hno rp1 SP1 rp2 SP2 Relief valve Control Counter pressure 2mm air gap per disc Stopping time longest / Control braking time Min Max Bar Bar Bar (Falling) (Rising) (Falling) (Rising) Bar Nm / Bar Sec CV11-C BSFI 28 8, 8, ,5/23 5.2/8.2 CV11-D BSFI 28 8, 8, ,5/23 5.2/8.2 Note: All pressures in bar. Pressures based on maximum calliper spring tolerance. The adjustable orifice, item 19, is opened approximately 1/16th of a turn, or set so the bleed down rate to bar of residual pressure after accumulator exhaustion is within 1 seconds: o Open too far and the counter pressure setting cannot be held, o Close too far and the pressure fall from the counter pressure setting after accumulator exhaustion will be greater than 1 seconds. 4. Bleeding the Brakes: a. The calliper hydraulic system must always be bled in conjunction with assembly, repairs, or when making changes in the system. b. Bleeding should be repeated several times a year, as any air in the system will impair its function. c. The calliper must be bled at the highest point on the brake, bleed adaptor. Brake Pad Adjustment CV112: The air gap between the brake disc and brake pads is a critical parameter for the efficient operation of the brake and must be checked and adjusted frequently, in order to ensure predictable brake operation. This dimension should be maintained between 1 and 3 mm and it is essential that this is never permitted to exceed 3 mm. Therefore adjustment is required to maintain this tolerance, which is dependant on the duty of individual applications. Page 4 of 7

5 5. Procedure: a. Check the pad thickness. If less than 2.5mm replace pads before proceeding. b. Remove the cover. c. Apply minimum hydraulic pressure. d. When the piston is fully lifted, fit the flange nut on the center bolt and tighten untill you feel a firm resistance as the nut comes in contact with the adjusting screw. (The distance from the end of the center bolt to the adjusting screw must be 2mm). e. Use the spanner and turn the adjusting screw until the piston and brake pads are pressed against the brake disc. f. Turn the adjusting screw a third turn back counter clockwise. The air gap should be approximately 1mm between the pad and disc. g. Apply oil pressure to the calliper and remove the flange nut. h. Check that the air gap is 1mm and release the pressure again. i. Fit the cover. 6. Adjusting the brake all other conveyors: The caliper is a failsafe spring applied calliper released by hydraulic pressure and does not require to be hydraulically released to carry out brake adjustment. The procedure for adjusting this air gap is as follows (adjust both piston air gaps at the same time). a. Check the pad thickness. If less than 2.5 mm replace pads before proceeding. b. Disengage the calliper indicator holder, to allow rotation of the calliper air gap adjustment screw, by loosening the indicator holder screws. c. Using the air gap spanner, turn the air gap adjusting screw clockwise until firm resistance is felt, then turn counter clockwise ½ of a turn. The air gap should be approximately 1mm between the pad and disc. d. Pressurize the calliper, and check that the air gap is 1mm. e. Refit the indicator holder screws. 7. Replacing the Brake Pads The calliper is a fail-safe spring applied calliper released by hydraulic pressure and does require to be hydraulically released or pressurised to carry out brake adjustment and when replacing the pads. The procedure for replacing brake pads is as follows (replace both brake pads at the same time): a. Check the pad thickness. If less than 2. mm of organic material bonded to the steel backing plate, replace pads. b. Remove the indicators. c. Remove the cover. d. Apply hydraulic pressure to the calliper and fit the flange nut. Release the pressure again. e. Unscrew the adjusting screw until the distance to the yoke is 12mm for standard S callipers or 1 mm for offshore R callipers. Air Gap Adjustment Spanner f. Remove the pad retraction springs and screws. g. Remove the pad holder. h. Remove the worn pads and fit the new ones. i. Re-fit the pad holder. j. Fit the pad retraction springs and screws through the yoke and into the pads. k. Adjust the air gap, l. Replace the cover. m. Refit the indicators Page 5 of 7

6 8. Brake Pad Alignment Inspecting the alignment of the brake: a. Lift the pistons using oil pressure. b. Measure the distance between the calliper arms and the brake disc on both sides of the disc. c. The difference between the measurements must not exceed 1mm. Check that the bracket is in contact with the base throughout its entire surface. If not, shim up as necessary. d. Check that the disc's angular throw in relation to the support does not exceed the permissible values. Note: The axial movement of the brake disc must not exceed.5mm. In cases where this distance is exceeded, the air gap must be adjusted accordingly. e. Activate the brake by removing the hydraulic pressure. Check that the bracket is in contact against the base along its entire surface. If not, shim up as necessary. f. Apply hydraulic pressure to lift the pads again. g. Check that the brake disc rotates freely throughout its diameter and that the brake is aligned parallel to the brake disc. To allow for expansion due to temperature increase, a clearance of 1mm per meter of disc diameter is recommended between bracket and disc. 9. Bedding in of Brake Pads To obtain the rated coefficient of friction between the pad and the brake disc, it is essential that the pads are bedded to the disc surface. To obtain the rated coefficient of friction between the pad and the disc brake, and to ensure the pad surface is aligned to the disc, it is essential that the pads are bedded to the disc surface. The coefficient of friction may drop by approx. 2% when not bedded in. This can be done by making a series of load tests with increasing load or speed, until sufficient coefficient of friction is achieved. If the brake disc is new, the time of bedding in will be longer because the disc also has to be bedded in. Always use new pads with a new disc, never use used pads with a new disc. Organic pads: These can normally be bedded in by driving the disc through the pads with a minimum of 25% of the rated clamping force applied, or if that is not possible, by making a series of activations with increased load, or increased speed. Sintered metal pads: These can normally be bedded in by driving the disc through the pads with a minimum of 4% of the rated clamping force applied, or if that is not possible, by making a series of activations with increased load, or increased speed. During the process of bedding in, the disc temperature should be monitored to ensure that the disc does not overheat, beyond pad maximum peak temperature limits. Organic material BE 3521 Organic material IP 16 Sintered metal material MD C 35 C 9 C Recommended System Spares and Tools Tools Application Maintenance Spares Application Critical Spares Application Calliper Air gap adjusting spanner BSFI 2 Calliper Air gap adjusting spanner BSFI 3 Calliper Brake pad set BSFI 2 organic non asbestos D 213 Calliper Brake pad set BSFI 3 organic non asbestos BE Power Unit Spin on breather Power Unit N/A Oil filter element Power Unit N/A Accumulator Power Unit Pressure switch digital 24 VDC Power Unit Solenoid coil 24 VDC Page 6 of 7

7 POST-TASK ACTIVITIES HOUSEKEEPING: Ensure all tools are collected and returned to stores. Remove all waste materials from area and place in the appropriate bins. Report any damaged equipment. Leave aisles clear and area free of hazards. SIGN-OFF WHEN WORK IS COMPLETED Do subsequent Notifications exist for all items requiring attention? Yes No Have the required Notifications been raised? Yes No List Notification Numbers: Inspection conducted by: Name: Sign: Date: Supervisor Name: Sign: Date: Page 7 of 7