But merely switching to ISO Grade 68 mineral oils will be risky for bearings that depend on oil rings for lube application - Lube Pump company. Appropriately formulated with the ideal base stock and with exclusive ingredients, ISO VG 32 synthetics are rather acceptable from movie strength and film thickness points of view. In reality, the efficiency of some ISO VG 32 synthetics replicates that of ISO VG 68 mineral oils.
Superior synthetics attain high movie strength through exclusive additives, so there can be considerable differences in the efficiency of 2 lubricants of the same viscosity and base stocks. Just one may be suitable for the highest dependability services. The idea that a person oil type or viscosity matches all applications is hardly ever right.
Custom-made oil rings may be required to work with the thicker oils at certain high shaft peripheral velocities. Although artificial lubes cost more than mineral oils at the point of initial purchase, strenuous and comprehensive expense validations will often reveal reasonably short payback durations. Integrating extended bearing life and extended drain periods outcomes in much better repayment.
Therefore, upgrading to the best-available bearing protector seals and implementing plant-wide oil-mist lubrication are 2 primary techniques embraced by world-class plants. Air and the lube take up whatever real estate area is not really used by the bearings. For bearings to endure, strong particles and water intrusion need to be prevented. For this reason, proper bearing housing defense seals are important for keeping the oil clean.
Keeping the oil clean is the first order of service if extended oil replacement intervals are the goal - driveshaft disconnect companies. In turn, attaining prolonged oil replacement periods typically makes it affordable to use superior-quality artificial lubricants. In mix, advanced bearing protector seals and synthetic lubes develop an environment favorable to long bearing life.
Because synthetic lubricants are more expensive than mineral oils, some users cling to mineral oils for their procedure pumps. They likewise may utilize insufficient bearing housing seals since their only issue is the preliminary purchase rate. Wear-prone seals include lip seals and likewise certain rotating maze seals. Seals to avoid are those that permit a turning O-ring to contact the sharp edges of an O-ring groove, or O-ring grooves that are wide sufficient to prevent such contact but that enable massive amounts of contaminants to go into the bearing housing.
Yet lip seals typically last only about 2,000 operating hours (3 months). When lip seals are too tight, they cause shaft wear and in some cases lube discoloration called "black oil." When lip seals have actually worn and no longer seal securely, oil is lost through leakage, or impurities discover their way into bearing housings. driveshaft disconnect.
Small steam turbines typically suffer from steam leak at both drive and governor-end sealing glands. Each bearing real estate lies surrounding to among these two glands, which include carbon rings (Lube Pump company). As quickly as the internally split carbon rings start to wear, high-pressure and high-velocity leakage steam finds its method into the bearing housings.
Figure 2. This cross-section view shows a small steam turbine motorist for process pumps.( Ref. Worthington-Turbodyne) The bearing real estate protector seal in Figure 3 was created for steam turbines. It includes a little- and large-diameter dynamic O-ring. This bearing protector seal is highly stable and not most likely to wobble on the shaft; it is also field-repairable.
The larger cross-section O-ring is then free to move axially, and a micro-gap opens up. Figure 3. This cross-sectioned half-view highlights a sophisticated bearing housingprotector seal for small steam turbines - Lube Pump suplies.( Ref. AESSEAL Inc.) When the turbine is stopped, the external of the 2 vibrant O-rings will return to its standstill position.
In this design, the bigger cross-section O-ring touches a reasonably big contoured location. Because contact pressure equates to force divided by area, an excellent style goals for low pressure. In outdated configurations, contact with the sharp edges of an O-ring groove risks O-ring damage, and slivers of O-ring product can wind up polluting the lube oil.
Modern items fit in the space previously taken up by lip seals. Lube Pump company. In 2009, when a Dutch refinery asked for the setup of the bearing protector seal displayed in Figure 3 for among its steam turbines, no adjustments were permitted on the existing devices. Installation of 3 bearing protector seals on the very first maker needed to take location during a scheduled plant shutdown.
A conventional lip seal (top) versus a contemporary turning labyrinthbearing real estate protector seal( bottom). (Ref. AESSEAL Inc (Lube Pump companies).) Without any in-depth drawings of the bearing real estates readily available, the precise setup geometry could just be finalized after dismantling the small turbine seen in Figure 2. Among the primary problems was the brief outboard length - less than 0.
But the producer's engineers were able to customize the advanced design to suit the existing groove of the initial equipment manufacturer's maze seals. Shipment was made within one week of taking measurements of the steam turbine and bearing real estates, and the turbine has actually been running perfectly for many years. The point is that extremely affordable devices upgrades are possible at hundreds of refineries.
Compared with standard items typically used in pumps, the type described here provides important advantages, such as being suitable for heats, integrating Aflas O-rings as the basic elastomer, offering additional axial clearance to accommodate thermal expansion and utilizing high-temperature graphite gaskets. With these benefits in mind, there need to no longer be any reason for water intrusion into the bearing real estates of process pumps and small steam turbine chauffeurs at reliability-focused facilities.
Of course, these and comparable issues are prevented with pure oil-mist systems. These systems get rid of much of the human aspect and are less maintenance-intensive than standard pumps and chauffeurs lubed with vulnerable oil rings and constant-level lubricators. As mentioned formerly, thick oils can be rather tough to use with the oil rings that are typically provided with API process pumps (driveshaft disconnect).
Neither oil rings nor constant-level lubricators are utilized in pumps and motorists linked to plant-wide oil-mist systems. Figure 5. This chart reveals how changes in lube application, oil type and lube viscosity tend to affect percentage reductions in bearing friction. (Ref - Lube Pump suplies. E. Villavicencio) Oil mist is an atomized quantity of oil carried or suspended in a volume of pressurized dry air.
The point of origin is usually an easy blending valve (the oil-mist generator) connected to a header pipe. Branch lines frequently feed hundreds of rolling aspects in pumps and chauffeurs linked to the header. Figure 6. This chart shows how changes in lube application, oil type and lube viscosity affectbearing temperature.( Ref.
Villavicencio) At dead stop, or while on standby, pump and driver bearings are protected by the surrounding oil mist, which exists in the bearing real estate area at a pressure just barely higher than ambient. These pump and motorist bearings are lubricated from the time when atomized oil beads join to become larger oil beads - Lube Pump.
There are also plant-wide oil-distribution systems whereby liquid oil (not an oil/air mixture) is pressurized and injected through spray nozzles into the pump bearings. These oil-spray systems are not to be confused with the more cost-effective oil-mist systems. However, both oil-mist and oil-spray applications can take credit for lower frictional losses (see Figures 5 and 6) and need to be considered when doing cost-justification analyses.