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US 4,391,571 AGranted
Pumping apparatus for pumping liquids such as slurrys
OwnerThomas A. Craggsinventor
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OwnerThomas A. Craggsinventor
Estimating the term…
A pumping apparatus for pumping liquids such as slurrys comprises a pumping cylinder/piston (6,8) driven by the piston/cylinder (16,18) of an operating device, the supply of fluid under pressure either to an upper port (16a) of the cylinder (16), or the lower port (16b) of the cylinder, being controlled by valve mechanism (28). The valve mechanism is moved between two conditions, in which it supplies fluid under pressure to one or other of said ports consequent upon the arrival of a member (20) connecting the two pistons (8,18) at one or other of its extreme positions of movement. Alternatively, or in addition, the fluid pressure circuit powering the operating device includes a regenerative branch, through which fluid under pressure flows from the low pressure side of the operating device directly back to the high pressure line of the fluid circuit, upstream of the motor supplying fluid under pressure. In this manner, the apparatus can operate both at an initial high speed, under relatively low resistance to pumping, while utilizing a power source which is smaller than would otherwise be required. In this manner, not only is a saving of energy obtained, but (because of a reduction of work done on the fluid) water cooling of the fluid circuit may be dispensed with.
Apparatus for use in the pumping of a slurry and comprising a pumping device comprising a cylinder and a piston mounted therein, and which is operative to cause liquid to be drawn through an inlet port and expelled through an outlet port, an operating device comprising a cylinder and a piston mounted therein, a fluid pressure circuit which includes a fluid sump, a pump operative to pump fluid under pressure to the operating device, and valve mechanism operative to control the admission of fluid under pressure to the operating device, a connecting member extending between the piston of the pumping device and the piston of the operating device,
Apparatus for use in the pumping of a slurry and comprising a pumping device comprising a cylinder and a piston mounted therein, and which is operative to cause liquid to be drawn through an inlet port of the cylinder and expelled through an outlet port thereof, an operating device comprising a cylinder and a piston mounted therein, a fluid pressure circuit which includes a fluid sump, a pump operative to pump fluid under pressure to the operating device, and valve mechanism operative to control the admission of fluid under pressure to the operating device, and a connecting member extending between the piston of the pumping device and the piston of the operating device, wherein during an initial part of each pumping operation of the apparatus, part of the fluid flowing from the low pressure side of the fluid pressure circuit is returned directly to the high pressure side of the fluid pressure circuit, and part is returned to the sump of the fluid pressure circuit.
Dependencies are inferred from the claim text.