Dual-stage cryogenic pump

Patent metadata

Field	Value
Publication number	US-9970421-B2
Application number	US-201514668478-A
Country	US
Kind code	B2
Filing date	Mar 25, 2015
Priority date	Mar 25, 2015
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A pump for use in pressurizing a cryogenic fluid. The pump may have a barrel, and a boost enclosure disposed around the barrel. The pump may also have a boost plunger disposed inside the barrel and configured to discharge fluid into the boost enclosure. The pump may further have a main plunger disposed inside the barrel and configured to receive fluid from the boost enclosure and to increase a pressure of the fluid.

First claim

What is claimed is:

1. A pump, comprising:
a barrel;
a boost enclosure disposed around the barrel;
a boost plunger disposed inside the barrel and configured to discharge fluid into the boost enclosure; and
a main plunger disposed inside the barrel and configured to receive fluid from the boost enclosure and to increase a pressure of the fluid, wherein the main plunger is free floating and configured to be moved to a retracted position by a pressure of the fluid in the boost enclosure.

2. The pump of claim 1 , further including a tank, wherein:
the boost enclosure and the barrel are located inside the tank; and
the boost plunger is configured to draw fluid into the barrel from a location inside the tank and separate from the boost enclosure.

3. The pump of claim 2 , wherein leakage from the main plunger is directed to the boost plunger.

4. The pump of claim 3 , wherein leakage from the boost plunger is directed into the tank.

5. The pump of claim 2 , further including a plurality of inlet passages connecting the tank to the barrel at the boost plunger.

6. The pump of claim 5 , further including at least one check valve configured to selectively close the plurality of inlet passages.

7. The pump of claim 6 , wherein the at least one check valve has a ring-shaped body configured to simultaneously inhibit flow through the plurality of inlet passages.

8. The pump of claim 7 , further including at least one internal recess formed in the ring-shaped body and configured to engage a guide formed in the barrel.

9. The pump of claim 7 , wherein each of the plurality of inlet passages is circular.

10. The pump of claim 7 , wherein each of the plurality of inlet passages is arcuate.

11. The pump of claim 5 , wherein a combined cross-sectional area of the plurality of inlet passages is equal to 0.4-0.7 times an exposed cross-sectional area of the boost plunger.

12. The pump of claim 1 , further including a mechanical input device connected to the boost plunger.

13. The pump of claim 12 , wherein an extending movement of the boost plunger causes the main plunger to extend.

14. The pump of claim 12 , wherein the mechanical input device includes:
a rotatable load plate; and
a pushrod transmitting an undulating axial motion of the rotatable load plate to the boost plunger.

15. A pump, comprising:
a tank;
a barrel disposed inside the tank;
a boost enclosure disposed inside the tank;
a boost plunger disposed inside the barrel and configured to discharge fluid into the boost enclosure;
a mechanical input device connected to the boost plunger;
a plurality of inlet passages connecting a location inside the tank and separate from the boost enclosure to the barrel at the boost plunger; and
a main plunger disposed inside the barrel and configured to receive fluid from the boost enclosure and to increase a pressure of the fluid, the main plunger being free floating and configured to be moved to a retracted position by a pressure of the fluid in the boost enclosure and configured so that an extending movement of the boost plunger causes the main plunger to extend,
wherein a combined cross-sectional area of the plurality of inlet passages is equal to 0.4-0.7 times an exposed cross-sectional area of the boost plunger.

16. The pump of claim 15 , wherein:
leakage from the main plunger is directed to the boost plunger; and
leakage from the boost plunger is directed into the tank.

17. The pump of claim 15 , further including at least one check valve configured to selectively close the plurality of inlet passages, the at least one check valve having a ring-shaped body configured to simultaneously inhibit fluid flow through the plurality of inlet passages.

18. A pump, comprising:
a tank;
a barrel disposed inside the tank;
a boost enclosure disposed inside the tank and around the barrel;
a boost plunger disposed inside the barrel and configured to discharge fluid into the boost enclosure;
a plurality of inlet passages connecting a location inside the tank and separate from the boost enclosure to the barrel at the boost plunger;
at least one check valve configured to selectively close the plurality of inlet passages;
a free-floating main plunger disposed inside the barrel and configured to receive fluid from the boost enclosure and to increase a pressure of the fluid;
a rotatable load plate; and
a pushrod connected to the boost plunger and configured to transmit an undulating axial motion of the rotatable load plate to the boost plunger,
wherein:
a combined cross-sectional area of the plurality of inlet passages is equal to 0.4-0.7 times an exposed cross-sectional area of the boost plunger;
leakage from the free-floating main plunger is directed to the boost plunger; and
leakage from the boost plunger is directed into the tank.

Assignees

• Caterpillar Inc

Inventors

• Coldren Dana R
• Mahmood Sana

Classifications

• F04B19/003 Primary

  free-piston type pumps · CPC title

• F04B15/00

  Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts · CPC title

• F04B1/12 Primary

  having cylinder axes coaxial with, or parallel or inclined to, main shaft axis · CPC title

• F04B9/117

  the pumping members not being mechanically connected to each other · CPC title

• F04B23/02

  having reservoirs · CPC title