Free piston linear motor compressor and associated systems of operation

Patent metadata

Field	Value
Publication number	US-10323628-B2
Application number	US-201414536174-A
Country	US
Kind code	B2
Filing date	Nov 7, 2014
Priority date	Nov 7, 2013
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A linear motor compressor including a compressor housing and a cylinder housing having a plurality of opposing compression chambers. A piston freely reciprocates within the cylinder housing using a linear electric motor.

First claim

We claim:

1. A linear motor compressor comprising:
a compressor housing;
a cylinder housing having a plurality of opposing compression chambers;
a piston freely reciprocating within the cylinder housing, wherein the piston reciprocates without assistance from a mechanical spring;
a linear electric motor directly coupled to the piston and positioned to reciprocate the piston via a motor electric current powering the motor;
a flexible coupling between the piston and an armature of the linear electric motor; and
a piston position feedback control system with adaptive motor current output to directly power and control the linear electric motor and thereby minimize energy required to do work, the piston position feedback control system including a controller in combination with a position feedback system that tracks a position of the piston within the cylindrical housing and wherein the controller adapts or adjusts the motor electric current to the linear electric motor in response to the position of the piston to maintain an optimized piston position and frequency.

2. The linear motor compressor of claim 1 wherein compression is achieved with a single primary moving part.

3. The linear motor compressor of claim 1 wherein the cylinder housing includes the piston freely reciprocating within the cylinder housing, wherein compression discharge from an outlet of a chamber of one side of the opposing compression chambers feeds an inlet of another chamber.

4. The linear motor compressor of claim 1 wherein the piston operates at resonant frequency.

5. The linear motor compressor of claim 1 wherein the plurality of opposing compression chambers comprise a series of stepped diameter compression chambers positioned at opposing ends of the cylinder housing.

6. The linear motor compressor of claim 1 , wherein the plurality of opposing compression chambers comprise compression chambers of a single diameter at opposing ends of the cylinder housing.

7. The linear motor compressor of claim 1 wherein the compressor housing is pressurized with a process fluid.

8. The linear motor compressor of claim 1 , wherein the compressor housing comprises a blowdown volume for depressurizing the compressor and related systems.

9. The linear motor compressor of claim 8 , wherein the cylinder housing includes the piston freely reciprocating within the cylinder housing, wherein compression discharge from an outlet of a chamber of one of the opposing compression chambers feeds an inlet of another chamber and a first stage of compression is drawn from the blowdown volume.

10. The linear motor compressor of claim 1 wherein a process fluid is hermetically sealed within the linear motor compressor.

11. The linear motor compressor of claim 1 further comprising at least one of a rigid piston and a flexible coupling between the piston and an armature of the linear electric motor.

12. The linear motor compressor of claim 1 wherein the linear electric motor comprises a reluctance motor with dual opposing winding cores.

13. The linear motor compressor of claim 1 wherein the linear electric motor comprises one of a permanent magnet motor, an induction motor, a voice coil motor, a reluctance motor, or a homopolar induction motor.

14. The linear motor compressor of claim 1 further comprising integrated motor and process fluid cooling for heat removal.

15. The linear motor compressor of claim 1 wherein the piston position feedback control system comprises a linear encoder feedback loop to track a position of the linear electric motor or the piston.

16. The linear motor compressor of claim 1 further comprising a low friction coating in combination with a seal material optimized for a process fluid to reduce energy consumption and increase seal life.

17. The linear motor compressor of claim 1 further comprising at least one fully integrated motor stator.

18. The linear motor compressor of claim 1 wherein the flexible coupling allows for independent alignment of the piston and the armature.

19. A linear motor compressor assembly comprising:
a compressor housing;
a multi-stage cylinder housing having a plurality of opposing compression chambers;
a piston bi-directionally driven and freely reciprocating within the multi-stage cylinder housing without the assistance from a mechanical spring;
a linear electric motor positioned to reciprocate the piston, wherein the linear electric motor includes an armature and the assembly is hermetically sealed;
a flexible coupling between the piston and the armature of the linear electric motor; and
a piston position feedback control system adapted to track a position of the piston and adjust the current to the linear electric motor up or down in response to the tracked position of the piston in order to directly control and maintain an optimized frequency of the linear electric motor or the piston.

20. The linear motor compressor of claim 19 wherein the flexible coupling allows for independent alignment of the piston and the armature.

21. A gas compression station comprising:
a compressor housing;
a multi-stage cylinder housing having a plurality of opposing compression chambers;
a bi-directional piston reciprocating within the multi-stage cylinder housing without a mechanical spring;
a linear electric motor positioned to reciprocate the piston, the linear electric motor including an armature directly coupled to the piston by a flexible coupling, wherein the compressor chambers and the linear electric motor are hermetically sealed within the compressor housing;
an outlet for discharging a fluid from a final stage of compression; and
a piston position feedback control system with adaptive current output to minimize energy required to do work, wherein the piston position feedback control system comprises a linear encoder feedback loop to track a position of the linear electric motor or the piston, and the piston position feedback control system adjusts the current to the linear electric motor up or down as a function of the position of the linear electric motor or the piston in order to directly control and maintain an optimized frequency of the piston.

22. The linear motor compressor of claim 19 wherein the piston position feedback control system tracks a position of the piston through active inductance measurements.

Assignees

• Stair Jason
• Lindsay Anthony
• Lewis Michael
• Zowarka Raymond
• Pratap Siddharth
• Hearn Clay
• Penney Charles
• Worthington Michael
• Liu Hsing Pang
• Gas Technology Inst
• Univ Texas

Inventors

• Stair Jason
• Lindsay Anthony
• Lewis Michael
• Zowarka Raymond
• Pratap Siddharth
• Hearn Clay
• Penney Charles
• Worthington Michael
• Liu Hsing-Pang

Classifications

• F04B25/02

  of stepped piston type · CPC title

• H02K33/12

  with armatures moving in alternate directions by alternate energisation of two coil systems · CPC title

• F04B31/00

  Free-piston pumps specially adapted for elastic fluids; Systems incorporating such pumps (muscle-driven pumps in which the stroke is not defined by gearing F04B33/00) · CPC title

• F04B19/003 Primary

  free-piston type pumps · CPC title

• F04B35/045

  using solenoids · CPC title