Flow dividers are versatile components which, when properly applied, will save on installation and operating costs, increase circuit versatility, offer convenience, and improve pump life. Flow dividers are assembled from standard heavy-duty gear pump components available from Commercial Shearing.
A few ideal applications are:
* As flow equalisers to synchronise the operation of multiple cylinders and motor.
* As flow dividers to distribute the pump flow according to the requirements of each pump.
* As pressure intensifiers to increase the pressure available to a particular system beyond the pump's relief valve setting or to reduce the time at which the pump must operate at maximum pressure.
Flow dividers offer advantages often overlooked when designing a hydraulic circuit. They are unique components, which can be considered to 'float' in the hydraulic circuit, working only when required, and then, only to the extent necessary. Unlike variable orifice types, flow dividers operate on the principle that fluid horsepower input equals fluid horsepower output, less, of course, the small efficiency loss of the unit. If the pressure at an outlet is lower than the inlet pressure, the low-pressure section of the rotary flow divider acts as a motor. The energy expended across the motor is not wasted in generating heat but is applied through the interconnecting shaft to do work in the other sections. The total output flow is equal to the input flow. Each section output is in proportion to the gear width of the section. As a flow equaliser, each section has equal gear widths. Flow dividers operate automatically. No pilot signals or other devices are necessary to initiate their operation. The economic advantages of flow dividers are best illustrated by the components they eliminate. Expensive multidrive gearboxes, multiple pumps, and extensive plumbing and fittings can be replaced by a single pump and flow divider remotely mounted in any convenient location. Problems, common in feeding multiple pumps, are eliminated because flow dividers are pressure-charged. Flow dividers can be mounted in any position and, because they are self-lubricating, require no maintenance. No external drain lines or shafts are required. Extended studs are provided for easy mounting.
Standard porting of the FD30, 50, and 75 flow dividers are through the gear housing and bearing carrier. Porting through the port end covers is available on special request. Two studs extend from each end of the flow divider for easy mounting.
Flow dividers can be used in the following practical applications:
* Concrete pump.
Concrete circuit pump providing intermittent high pressure and some speed variation. The two-section flow divider works in pressure intensification and speed control mode, the four-section flow divider simply splits flow to machine services.
* Drill rig.
Flow division is combined with a variable speed drill operation. Two primary flows go to the drill motor, third flow feeds auxiliary services, fourth flow is further divided to supply additional machine services including drill rod screwing and unscrewing.
* Mining machine.
Use of flow dividers and mid-inlet valves on this mining machine circuit give maximum utilisation of power as well as eliminating the need for a complex and costly gearbox-driven, multiple pump unit.
* Container handler.
Flow divider with priority outlet valves assures constant, independent flow to essential services on container side loaders - steering and remote control circuit. Other flows supply lifting and auxiliary services.
* Excavator.
Excavator circuits use the specialised features of flow dividers and mid-inlet sections in valves to give intermittent high pressures to essential machine services.
* Telescopic cranes.
Flow dividers with a priority outlet valve combine to guarantee power to the steering circuit. Second flow provides two-speed lifting. Secondary flow of priority valve helps supply auxiliary services.
Flow dividers operate most efficiently with gear sizes of 1" (2,5 cm) or larger and at speeds from 700 to 1300 rpm. Therefore, when sizing a flow divider, it is important to keep these two points in mind. It is also good practice to avoid specifying flow dividers with all 1/2" (1,3 cm) or 1/4" (0,6 cm) gears. Whenever possible position the inlet port nearest the largest gear unit. Normally, the largest gear section should be in the centre of the unit. Any flow divider has the potential for pressure intensification. Adequate relief valve protection on the discharge side of the flow divider section is necessary to keep intensification within the limits of the unit.
© Technews Publishing (Pty) Ltd | All Rights Reserved
printer friendly version