Standard hydraulic IMM with variable-displacement pump
The actuator (8) velocity is controlled by adjusting the speed, displacement, or both, of an axial-piston variable-displacement pump
The A7VK axial piston variable-displacement pump
is specifically designed for high-pressure pumping of polyol and isocyanate used in making polyurethane.
15) uses a pressure-compensated, variable-displacement pump
instead of the combination of fixed-displacement pump, accumulator and unloading valve (Fig 14).The characteristics of this demand flow circuit are the same as those in the aforementioned combination.
In this application, the diesel engine drives a variable-displacement pump
and a motor, which operate in a closed circuit.
Model 55 and Model 90 are both reported to offer energy efficiency, reduced noise levels, and highly repeatable accuracy, made possible primarily by an electronically regulated variable-displacement pump
. Precise and consistent part molding is achieved by an electronically programmable and regulated oil temperature control, adds the company.
Injection machines using fixed-speed electric motors progressed from simple hydraulic drives, using a fixed-displacement pump, to the more modern and efficient variable-displacement pump
. Variable-displacement pumps
can be more energy efficient; however, it is possible that when servo and proportional valves are used to provide a high degree of precision in pressure and flow control, energy losses can still be significant.
speed for a variable-displacement pump
. The four curves shown are for stroke position corresponding to 100 percent maximum displacement, 75 percent, 50 percent and 25 percent respectively Constant pressure is assumed.
The HA-SV version uses a Japanese (Daikin) servomotor to drive the pump system, while the standard HA version employs an electric variable-frequency motor to drive a variable-displacement pump
The press also features an energy-efficient, variable-displacement pump
with proportional valves for velocity and pressure control; a two-tiebar clamping system with maintenance-free, greaseless tiebars; and a compact 13 x-5 ft footprint.
Options: Hydraulic core pull or unscrewing device, extended nozzle, accumulator for high-speed injection, variable-displacement pump
, hydraulic oil-temperature control.
A compact, axial-piston, variable-displacement pump
, specially designed for high-pressure pumping of urethane polyol and isocyanate, is newly available from Bosch Rexroth Corp., Lehigh Valley, Pa.