Steele Extrusion Machinery Vacuum System The Best in Clay Machinery Since 1889 J.C. STEELE & SONS, INC. P.O. Box 1834 Statesville, NC USA 28687 TEL: (704) 872-3681 FAX: (704) 878-0789 web site: www.jcsteele.com e-mail: info@jcsteele.com Rev 6/2007
VACUUM SYSTEM - Page 1 Low or inadequate vacuum can result in changes in the extruded column surface texture, the appearance of auger cracks or swirls in the column, and other problems. During the initial startup of the vacuum system and at least once a month (or whenever problems arise) thereafter check your vacuum system to find out if everything is working as it should and to locate and fix any problems. The operation of the vacuum pump requires a continuous supply of clean service liquid (oil). The oil is drawn into the pump on the suction side and is discharged with the compressed gas. Inside the pump, the oil is used to help create vacuum. It also carries away heat generated by the pump; that s why a heat exchanger (oil cooler) is built into the oil piping. OIL COOLER SEE PACKING GLAND DETAIL COMPOUND PRESSURE GAUGE SEE TANK VENT DETAIL OIL FLOW VALVE EXTERNAL LUBRICATION LINES TO VACUUM PUMP PACKING GLANDS (NOT ON ALL SYSTEMS) The oil temperature should never exceed 180 F. J.C. Steele has available a dial temperature gauge for installation in the upper (vacuum pump oil supply) tank. See Item "E" on the LIST OF LUBRICANTS at the end of this section for acceptable oils. Do not mix different brands or types. Before Operating the Vacuum Pump for the First Time OIL DRAIN FITTING WATER DRAIN VALVE FIGURE 1 OIL CIRCULATING PUMP 1. Remove oil fill plug on top of the upper tank and fill with two 55 gallon drums of oil. Oil will overflow into the lower tank. Replace the fill plug. 2. Start the vacuum system, run for approximately 5 minutes, then turn it off. 3. Add oil to the lower tank (at the fill tube) until the level is two or three inches below the top of the sight glass (most of another 55 gallon drum). 4. Mark the oil level with a piece of tape. 5. Loosen packing glands (see page 6) two turns. After start-up, tighten until 1 or 2 drops per minute are achieved. HIGH CAPACITY OIL COOLER OIL CIRCULATING PUMP PRESSURE GAUGES OIL FILTER ASSEMBLY FIGURE 2 - New Style Oil Cooling Circuit 6-2007 Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery
Page 2 - VACUUM SYSTEM Changing the oil For normal one-shift operation, the system oil should be changed at least once a year. 1. After the system has been shut off for at least two hours, drain oil from both the upper and lower tanks by removing the large drain caps. 2. Flush the tank out, if necessary, to remove all debris. Keep at least two filter elements in stock - clean one with water and let it dry while the other is in use. A dust-trap baffle can be fabricated from steel plate and installed in-line before the filter to reduce the amount of dust that gets to the filter. Contact J.C. Steele & Sons for details. Another approach is to plumb two filters in parallel with shut-off valves installed on each side of both filters. One filter can be used while the other is being cleaned. Some older systems are not fitted with the large drain caps. Use whatever pipe fittings are available on the tanks (generally, smaller pipe plugs located on the underside of the tank) to drain oil. 3. Using the same brand of oil used previously, re-fill the system using the first time filling procedure. A little less oil will be required since some oil remains in the oil cooler and the vacuum pump. Fill to the tape marker installed previously. Failure to change the oil on a regular basis will reduce vacuum pump performance and eventually damage the pump. Oil Filter Systems fitted with the new-style cooling circuit (Figure 2) include a dual spin-on oil filter assembly. The head of the filter is equipped with a 15 psi by-pass valve. Pressure gauges are installed on the inlet and outlet side of the filter elements. When these gauges indicate a 10 psi difference, replace the filter elements. Vacuum Line Filter The filter continuously collects dust drawn from the vacuum chamber and should be cleaned on a daily basis. Any time the gauge on the chamber side of the filter indicates less vacuum than on the pump side, it could indicate that the filter requires cleaning. A damaged vacuum line check valve can allow vacuum pump oil into the filter under some circumstances. Replace the check valve if oil is found in the filter. This problem can also be avoided by venting the vacuum chamber before turning off the vacuum pump. Vacuum Pump Exhaust Filter Vacuum pump exhaust can be vented inside the plant if the optional coalescing filter (see Figure 3) is installed. Droplets of oil and water in the exhaust are coalesced and collected at the filter. The filter is fitted with two elements, one stacked on top of the other. The elements are designed for 12 to 18 months of one-shift operation. Dispose of water and oil in accordance with all applicable federal, state, and local requirements. Adjusting the Vacuum Pump for Best Performance At initial start-up, establish the correct amount of oil flowing into the vacuum pump to optimize performance. Incorrect oil flow will cause problems with the pump: If the flow is too high, the pump may vibrate excessively and performance may decrease. Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery 6-2007
VACUUM ABSOLUTE PRESSURE GAUGE OR VACUUM GAUGE VACUUM FILTER OPTIONAL COALESCING FILTER VACUUM LINE CHECK VALVE SHUT-OFF VALVE VACUUM SYSTEM - Page 3 VENT VALVE SHUT-OFF VALVE SEPARATOR TUBE PUG SEALER VACUUM CHAMBER ABSOLUTE PRESSURE GAUGE OR VACUUM GAUGE VACUUM PUMP VACUUM PUMP OIL FILL TUBE SIGHT GLASS OIL DRAIN FITTING OIL FILL PLUG UPPER TANK OIL LEVEL SIGHT GLASS OIL TEMP GAUGE OIL DRAIN FITTING LOWER TANK FIGURE 3 If the flow is too low, the pump may overheat and vacuum may be lost. Observing a compound pressure gauge at the oil inlet is the best way to be sure that oil flow is correct. J.C. Steele & Sons has a retrofit kit available if your system is not fitted with this gauge and the Oil Flow Valve as shown in FIGURE 1. 1. If not installed previously, install a vacuum gauge at the vacuum pump inlet, a shut-off valve on the pump side of the vacuum line check valve, and a shut-off valve and vent valve on the vacuum chamber. 2. Open the shut-off valve nearest the vacuum pump and close the shut-off valve at the vacuum chamber. 3. Fully open the oil flow valve and turn the vacuum system on. 4. Open the vent valve at the vacuum chamber until the gauge reading at the vacuum pump inlet goes up about 1" of mercury (less vacuum). 5. Allow the system to reach operating temperature. If the compound pressure gauge is installed, adjust the oil flow valve until the gauge 6-2007 Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery
Page 4 - VACUUM SYSTEM reads as close as possible to zero. If the gauge is not installed, complete step 6. 6. Slowly close the oil flow valve while observing the gauge at the pump inlet. At first, gauge readings will go down (more vacuum). As soon as the gauge reading starts up (less vacuum), open the valve 1/4 to 1/2 turn. If the oil is not contaminated and at the proper level, the oil flow valve should need little adjustment after it is set the first time. However, it is a good idea to check it on a regular basis since it could wear or change due to vibration. If necessary, repeat the above procedure. Whenever the compound gauge reading changes without the oil flow valve being adjusted, check the oil for proper level, excess water, or other contamination. How to determine if the system is producing acceptable vacuum: 1. Close the shut-off valve at the vacuum pump inlet. 2. Start the pump and observe gauge reading. Determine if the vacuum level is acceptable: With a properly operating vacuum system, the gauge should read vacuum at least equal to local barometric pressure (in inches of mercury, corrected to sea level) minus 1 1/2" minus 1" for every 1,000 feet you are above sea level. For example, if local barometric pressure is 29" of mercury and your plant is 2,000 feet above sea level, then the vacuum gauge should read at least 25 1/2" (29-1 1/2-2 = 25 1/2). To get a good barometric pressure reading, call a local airport or other nearby weather station just before you start the test. Check the oil level before machine start up each day. Using the water drain valve, drain water from the tank until the oil level returns to the tape marker. Dispose of water in accordance with all applicable federal, state, and local requirements. Vacuum System Trouble Shooting Vacuum systems are equipped with a standard vacuum gauge on the pug sealer vacuum chamber that reads vacuum in inches of mercury: LESS VACUUM UP -20-15 -10 J.C. Steele & Sons now offers an absolute vacuum gauge that greatly simplifies vacuum measurements. This electronic gauge displays absolute vacuum in inches of mercury It is more accurate than a mechanical dial gauge and if unaffected by elevation or changes in local barometric pressure. A grinding noise coming from the pump indicates that a small amount of air needs to be introduced into the system. If this is the case, slightly open the vent valve at the pug sealer vacuum chamber. DOWN MORE VACUUM -25-30 In. Hg 0-5 Do not run the vacuum pump for more than five minutes with pump deadheaded (upstream shut-off valve closed). The pump can be damaged. Standard Vacuum Gauge 3. If the vacuum reading is acceptable, open the shut-off valve at the vacuum pump inlet (next to check valve) and Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery 6-2007
VACUUM SYSTEM - Page 5 close the shut-off valve and vent valve at the vacuum chamber. 4. If the vacuum is not acceptable, check the system for the following problems: excessive water in the system worn or damaged packing glands low oil level as indicated by sight glass in lower tank low oil flow through the cooling circuit as indicated by low oil level in upper tank high oil temperature Correct the problem(s) and start over at step 2. 11. Stop the pug sealer and extruder. 12. When the gauge reading at the vacuum chamber stops dropping, close the shutoff valve at the pump and then turn the pump off. 13. Observe the gauge on the vacuum chamber. If the vacuum is acceptable (less than 3" of mercury change in one minute) then continue with step 15. 14. If the gauge reading is not acceptable, use a leak detector to locate and stop leaks on the pug sealer and extruder - around liner bolts, access doors, etc., and start over at step 9. If not originally installed, the upper tank oil level sight glass and temperature indicator can be retrofitted. 5. Start the vacuum pump and read the gauge on the pump inlet. 6. When the gauge reading stops dropping, close the shut-off valve at the vacuum pump and turn the pump off. 7. If the vacuum reading does not go up more than 3" of mercury in one minute, go to step 9. 8. If the gauge reading changes more than 3" of mercury in one minute, check for leaks in the plumbing between the vacuum chamber and the pump. Locate and repair the leaks, open the shutoff valve at the pump, and start over at step 5. 9. Open both shut-off valves (at the pump and at the vacuum chamber). 10. With the vacuum pump on, run the pug sealer and extruder until both are filled with clay. This should create seals at the sealing die in the pug sealer and at the shaper cap. It is a good idea to have gauges calibrated on a regular basis to make sure that readings are accurate. 15. Start the pug sealer, extruder, and vacuum pump. Read the pug sealer vacuum chamber gauge. If not acceptable (per step 2), then most likely a leak exists around the pugshaft OD through the packing behind the shredder, or the vacuum pump is being overwhelmed by the amount of material being processed through the machine (and therefore the amount of air to be removed). If too much material is the problem, then a larger capacity vacuum system is required. If an extrusion line is upgraded to higher capacity machines, the vacuum pump and motor should be replaced by larger units as well. Contact J.C. Steele & Sons for recommendations. 6-2007 Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery
Page 6 - VACUUM SYSTEM Vacuum pump exhaust can be vented inside the plant if the optional coalescing filter is installed. This filter is installed close to the vacuum pump (see Figure 3) and eliminates long runs of pipe to the outside of the plant. PACKING GLAND NUT Packing Lubrication Many systems in operation have external lubrication lines to the bearings on either end of the vacuum pump shaft. These lines are fed from the circulation pump outlet. If needle valves are plumbed into these lines, they should be fully open at all times. Newer systems are lubricated internally using service liquid (oil) from the vacuum pump. In either case, the packing nuts on the pump should be adjusted to provide at least one drop of oil per minute. Drain lines return this lubricating oil to the lower tank. DRAIN LINE PACKING GLAND DETAIL SEPARATOR PIPE The packing may not move freely at first when backing off the packing nuts. It may be necessary to loosen the nuts several turns and then tighten until approximately one drop of oil per minute is achieved. VENT TUBE TOP OF LOWER TANK Lower Tank Vent All systems should have a vent tube connecting the top of the lower tank to the separator pipe. This prevents the build-up of pressure in the lower tank. Newer systems have an inspection plug in the separator which is useful for cleaning out this vent pipe. INSPECTION PLUG TANK VENT DETAIL If ever oil is forced up the drain tubes, it means that the vent tube is plugged and pressure has built up in the lower tank. Remove the inspection plug and clear the vent line. If the plug is not installed, drill through the separator pipe in line with the vent tube and tap for 1/4" NPT. After inspecting and/or clearing the vent tube, install a 1/4" NPT pipe plug. Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery 6-2007
VACUUM SYSTEM - Page 7 LIST OF LUBRICANTS TYPE A B DESCRIPTION OF LUBRICANT EXTREME PRESSURE (EP) TYPE LITHIUM-BASED GREASE of NLGI consistency No. 2, having a TIMKEN OK load of 40 lbs. or more. DO NOT USE "ALL PURPOSE" OR BALL BEARING GREASES. This quality of grease or a higher quality is recommended. Using the best grease everywhere reduces chances for error. EXTREME-PRESSURE (EP) TYPE GEAR OIL ISO 220 EP (AGMA 5 EP). Use this oil when ambient temperatures are below 100 F (38 C) and when the normal production schedule is below 12 hours per day. Examples of acceptable products are: Chevron EP ISO 220, Shell Omala EP 220, Exxon Spartan EP 220, Mobilgear 630 EP. ISO 320 EP (AGMA 6 EP). Use this oil when ambient temperatures exceed 100 F (38 C) or when the production schedule consistently exceeds 10 to 12 hours per day. If this oil is used it should be kept above 60 F (maximum viscosity 1800 centistokes) to insure it will be thin enough to adequately lubricate the gearbox bearings on cold start-ups and thin enough to pump properly. If needed, use heater strips on the gearbox oil sump but monitor the oil temperature and lubrication system to determine how many heater strips are needed and when the heat should be applied. Examples of acceptable products are: Chevron EP ISO 320, Shell Omala EP 320, Exxon Spartan EP 320, Mobilgear 632 EP. ISO 460 EP (AGMA 7 EP). This is recommended on a case by case basis for heavily loaded or very hot applications. ISO 460 oil has over twice the viscosity at 100 F of ISO 220 oil and nearly three times the viscosity at 75 F. If this oil is used it should be heated above 75 F so it will be thin enough to adequately lubricate the gearbox bearings and to pump properly. Examples of acceptable products are: Chevron EP ISO 460, Shell Omala EP 460, Exxon Spartan EP 460, Mobilgear 634 EP. C D E F G H HEAVY COATING COMPOUND (OPEN GEAR LUBE), designed for slow running, rough cast gears. This viscous, adhesive lubricant may have a fibrous, stringy consistency. Examples of acceptable products include: Chevron Open Gear Lube, Mobil Mobiltac LL, Shell Malleus Compound 0. STIFF (OR HEAVY) WATER-REPELLENT GREASE, such as WATER-PUMP GREASE with added graphite if available and molybdenum disulfide or other additives to inhibit dispersal TRANSFORMER (preferred) or SPINDLE OIL, ASTM-60 viscosity grade. The characteristic of oil used in the Double-Tank Cooling/Sealing Assembly of a Rotary Vacuum Pump to be MINIMIZED is its tendency to "foam" or to emulsify with water. Examples of acceptable products are: Shell Diala A or B Transformer Oil, Shell Spindle Oil 10, Texaco Transformer Oil, Texaco Spindura 10, Exxon Univolt N61B, Mobil Velocite No. 6. MOTOR-OIL, SAE 20/40, unless instruction book for proprietary speed reducers directs otherwise. MOTOR OIL ASTM-150 (ISO Grade 32 or SAE-10W) is used in Air Line Lubricators. MACHINE OIL, AGMA 7 (ISO 460) for extruder & pug sealer thrust bearing assemblies (oil-filled). We specifically use the compounded oil Lubriplate 8 in all oil-filled thrust bearing assemblies. AGMA 7 EP gear oil can be used alternatively (see recommendations for B lubricants). 6-2007 Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery
Installation, Operation, Lubrication, and Maintenance - J.C. Steele Extrusion Machinery 6-2007