High pressure pump

Patent metadata

Field	Value
Publication number	US-10968900-B2
Application number	US-201615551868-A
Country	US
Kind code	B2
Filing date	Jan 29, 2016
Priority date	Feb 18, 2015
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A positive displacement pump for pumping a fluid mastic comprises a plurality of cylinders each having a piston arranged for reciprocal motion within the cylinder. Movement of the piston in a first direction draws the fluid into the cylinder and movement in a second, opposite direction pumps the fluid out of the cylinder. A variable speed electric motor is drivingly coupled to a cam arrangement providing a reciprocating drive to the pistons. The cam arrangement comprises cams shaped and arranged to drive each piston in the first direction over less than half of a rotational cycle and to drive each piston in the second direction over the remainder of the rotational cycle. The cams are arranged to drive the pistons out of phase with one another.

First claim

The invention claimed is:

1. A positive displacement pump for pumping a fluid mastic, the pump comprising:
a plurality of cylinders each having a piston arranged for reciprocal motion within the cylinder, whereby movement of the piston in a first direction draws the fluid into the cylinder and movement in a second, opposite direction pumps the fluid out of the cylinder; and
a variable speed electric motor drivingly coupled to a cam arrangement via a cam shaft and providing a reciprocating drive to the pistons, wherein the variable speed electric motor is an ac motor having an inverter and a forced convection fan arranged to provide cooling air to windings of the ac motor, and wherein the inverter has a closed loop vector drive control,
wherein the cam arrangement comprises cams shaped and arranged to drive each piston in the first direction over less than half of a rotational cycle and to drive each piston in the second direction over the remainder of the rotational cycle,
wherein the cams are arranged to drive the pistons out of phase with one another, and
wherein the cam arrangement includes, for each piston, a first cam and cam follower and a second cam and cam follower, 180° out of phase with the first cam and cam follower relative to the cam shaft, wherein the first and second cam followers are connected to each other such that the distance between the first and second cam followers is always the same, and cam surfaces are shaped to ensure that the cam followers maintain contact with the respective cams at all times.

2. The positive displacement pump of claim 1 , comprising three or more cylinders, wherein the cams are arranged to drive the pistons such that, at any position of the rotational cycle more than half of the pistons are being driven in the second direction.

3. The positive displacement pump of claim 1 , wherein the cams are arranged such that a change in the direction of movement of any piston from the second direction to the first direction occurs at an angle of less than 5 degrees of rotation of the cams after another piston has changed direction from the first direction to the second direction, thereby providing that an increased number of pistons are pumping fluid prior to each change of direction of a piston from the second direction to the first direction.

4. The positive displacement pump of claim 3 , wherein the angle of less than 5 degrees of rotation of the cams is an angle of less than 2 degrees.

5. The positive displacement pump of claim 1 , wherein the ac motor has a shaft encoder providing a signal indicating a position of a rotor to the inverter.

6. A positive displacement pump for pumping a fluid mastic, the pump comprising:
a plurality of cylinders each having a piston arranged for reciprocal motion within the cylinder, whereby movement of the piston in a first direction draws the fluid into the cylinder and movement in a second, opposite direction pumps the fluid out of the cylinder; and
a variable speed ac motor drivingly coupled to a cam arrangement via a cam shaft and providing a reciprocating drive to the pistons, wherein the variable speed ac motor has an inverter and a forced convection tan arranged to provide cooling air to windings of the variable speed ac motor, the inverter having a closed loop vector drive control, and wherein the cam arrangement includes, for each piston, a first cam and cam follower and a second cam and cam follower, 180° out of phase with the first cam and cam follower relative to the cam shaft, wherein the first and second cam followers are connected to each other such that the distance between the first and second cam followers is always the same, and cam surfaces are shaped to ensure that the cam followers maintain contact with the respective cams at all times.

7. The positive displacement pump of claim 6 , wherein the variable speed ac motor has a shaft encoder providing a signal indicating a position of a rotor to the inverter.

8. The positive displacement pump of claim 6 , wherein the cam arrangement comprises the cams shaped and arranged to drive each piston in the first direction over less than half of a rotational cycle and to drive each piston in the second direction over the remainder of the rotational cycle, and
wherein the cams are arranged to drive the pistons out of phase with one another.

9. The positive displacement pump of claim 8 , comprising three or more cylinders, wherein the cams are arranged to drive the pistons such that, at any position of the rotational cycle more than half of the pistons are being driven in the second direction.

10. The positive displacement pump of claim 8 , wherein the cams are arranged such that a change in the direction of movement of any piston from the second direction to the first direction occurs at an angle of less than 5 degrees of rotation of the cams after another piston has changed direction from the first direction to the second direction, thereby providing that an increased number of pistons are pumping fluid prior to each change of direction of a piston from the second direction to the first direction.

11. The positive displacement pump of claim 10 wherein the angle of less than 5 degrees of rotation of the cams is an angle of less than 2 degrees.

12. The positive displacement pump of claim 6 , wherein springs urge the cam followers to maintain contact with their respective cams.

13. The positive displacement pump of claim 6 , wherein the cam arrangement comprises the cams having constant velocity cam surface profiles.

Assignees

• Carlisle Fluid Tech Inc

Inventors

• Smith Alan

Classifications

• F04B23/06

  the pumps being all of reciprocating positive-displacement type · CPC title

• F04B15/02

  the fluids being viscous or non-homogeneous · CPC title

• F04B9/042 Primary

  the means being cams · CPC title

• F04B9/04 Primary

  the means being cams, eccentrics or pin-and-slot mechanisms · CPC title

• F04B1/0413 Primary

  Cams · CPC title