When it comes to proper maintainance and reliability of your stationary or mobile equipment, the ability to dispense lubricants and fluids in a timely manner is critical.
Of course each application is different, for example the required volume to a automotive engine is critically different than the volume required for a mining haul truck engine. Each application may or may not require metered flows, or a specific time required to fill tank.
This positive displacement system has an adjustable valve located away from the bearing to control lubricant flow. A group of valves are mounted in common manifolds and connected to individual bearings via feed lines.
This system uses the fluid pressure in the supply line to cycle the valves. The term “single line” refers to the one supply line used to transfer the lubricant from the pump to the metering valves (injectors). The term “ parallel” refers to the injectors or metering valves; each operates in parallel independent of the other valves. In this system should a single valve malfunction none of the others in the system will be affected. The pump dispenses lubricant into the fully primed supply line, building system pressure. The pressure enters the metering valve, forcing a pilot piston and a dispensing piston forward.
When all the dispensing pistons in the system have reached the end of their travel, the resulting backup of pressure will place the system in a stall condition until timer times out and allows the system to vent back to the reservoir or signals a pressure switch that the system has reached desired pressure and signals the timing control to de-activate allowing system pressure to vent. With pressure on the metering valves reduced, a combination of low pressure and spring action resets both pilot and dispensing pistons. The metering valve reloads and is ready for the next cycle. Volume adjustability is obtained by controlling the dispensing piston’s stroke.
This system is used with both oils (at approx. 850-psi and most greases suitable for a pressure lubrication system (at 2500 psi) with a NLGI No.2 or lighter rating at 70C. Individual pop-up indicators can be used on each valve to monitor lube system performance.
Like the previous system, a dual-line parallel system uses fluid pressure (up to 6000 psi) to cycle adjustable valves to positively dispense a measured shot of lubricant. In this case, the term “dual-line” refers to the two supply lines while “parallel” again describes the valve action.
System operation involves pressurizing, first one, and then the second supply line. The measuring valve is crossed between these two lines. As pressure builds, a pilot piston in each valve directs the lubricant to one side of the dispensing piston, delivering lubricant to the bearing (volume adjustability is determined by controlling piston stroke). When this piston completes its travel, pressure continues to build until a pre hydraulic reverser (located at the pump) reacts to this level and reverses the lubricant flow.
Supply line 2 now pressurizes and lines 1 vents back to the reservoir. This type of system can handle most oils and greases suitable for a pressure lubrication system. Individual pop indicators are available to monitor individual valve performance.
In this system, the pump is connected to each dispensing piston successively, and each piston is moved progressively by the lubricant flow. When all pistons have moved in succession in one direction, pump flow is diverted automatically to the opposite direction.
Bypass blocks have been developed, making it possible to add or delete lubrication points without disturbing existing piping. A singe-line series system is suitable for either grease or oil. It is used on all types of production-line equipment, including numerical control machines, machine tools, transfer machines, large presses, steel-mill and mining machinery.
The advantage of this type of system is that a flow blockage anywhere in the system keeps every divider block from cycling, thereby providing a centralized warning of system failure.
Specialized, sophisticated equipment is available to pinpoint the malfunction in cases where the additional cost of pinpointing is warranted. Equipment is also available to bypass the blocked point so that other machines serviced by the system can continue to function.
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