Positive displacement type liquid-delivery apparatus

• US 6,419,462 B1
• Filed: 07/28/2000
• Issued: 07/16/2002
• Est. Priority Date: 02/24/1997
• Status: Expired due to Fees

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Hongo, Akihisa, Horie, Kuniaki, Fukunaga, Yukio, Kamoda, Kenji, Tsukamoto, Kiwamu, Uemura, Shinya, Yamagishi, Hirotake
• Primary Examiner(s): Kwon, John
• Application Number:
  US09/627,779
• Time in Patent Office: 718 Days
• Field of Search: 417/394, 417/395, 417/472, 417/412
• US Class Current: 417/394
• CPC Class Codes: F04B 13/00 Pumps specially modified to deliver fixed or variable measured quantities
• CPC Class Codes: F04B 2205/07 Pressure difference over the pump
• CPC Class Codes: F04B 43/073 the actuating fluid being controlled by at least one valve
• CPC Class Codes: F04B 43/113 the actuating fluid being controlled by at least one valve
• CPC Class Codes: F04B 53/143 Sealing provided on the piston

Abstract

A positive displacement liquid-delivery apparatus includes a positive displacement pump 110 and a differential pressure control unit 142. The positive displacement pump 110 includes a liquid-delivery chamber 128 having a watertight housing 122 with one part formed of a flexible diaphragm 124, and a diaphragm driver 136 linked to the diaphragm 124 for deforming the same to discharge fluid from the liquid-delivery chamber 128. The differential pressure control unit 142 uniformly controls the differential pressure inside and outside the diaphragm 124 during the pumping process.

Claims

1. A positive displacement liquid-delivery apparatus comprising:

a positive displacement pump including a housing having a liquid-delivery chamber and a working space divided from said liquid-delivery chamber by a flexible diaphragm, and including a diaphragm driving unit linked to said diaphragm to discharge fluid from said liquid-delivery chamber by changing a volume of said liquid-delivery chamber; and

a differential pressure control unit for controlling a differential pressure between said liquid-delivery chamber and said working space so as to maintain the differential pressure between said liquid-delivery chamber and said working space at a constant value during a pumping operation of said positive displacement pump;

wherein said diaphragm driving unit is operable to change the volume of said liquid-delivery chamber while said differential pressure control unit maintains the differential pressure between said liquid-delivery chamber and said working space at the constant value.

2. A positive displacement liquid-delivery apparatus as claimed in claim 1, wherein the differential pressure control unit comprises:

a differential pressure sensor for detecting the differential pressure between said liquid-delivery chamber and said working space, and for generating a differential pressure signal based on the detected differential pressure; and

a control valve for controlling a flow rate of the fluid discharged from said liquid-delivery chamber based on the differential pressure signal generated by said differential pressure sensor.

3. A positive displacement liquid-delivery apparatus as claimed in claim 2, further comprising:

a flow sensor disposed on a discharge path from said positive displacement pump and operable to detect the flow rate of the fluid discharged from said liquid-delivery chamber, and to generate a flow signal based on the detected flow rate;

wherein said control valve is operable to control the flow rate of the fluid discharged from said liquid-delivery chamber based on the flow signal generated by said flow sensor when a pressure in said liquid-delivery chamber during the pumping operation exceeds a prescribed pressure value or when an absolute value of a rate of pressure variations exceeds a prescribed pressure variation value.

4. A positive displacement liquid-delivery apparatus as claimed in claim 1, wherein said liquid-delivery chamber is arranged so as to achieve a required discharge flow volume of the fluid in one stroke.

5. A positive displacement liquid-delivery apparatus as claimed in claim 1, further comprising a flow control unit including:

a flow sensor disposed on a discharge path from said positive displacement pump and operable to detect the flow rate of the fluid discharged from said liquid-delivery chamber, and to generate a flow signal based on the detected flow rate; and

a control valve for controlling a flow rate of the fluid discharged from said liquid-delivery chamber based on the flow signal generated by said flow sensor.

6. A positive displacement liquid-delivery apparatus as claimed in claim 1, wherein said diaphragm driving unit of said positive displacement pump comprises:

a drive unit; and

a rod having a first end linked to said drive unit such that said drive unit is operable to move said rod along a longitudinal axis of said rod in either direction, and having a second end linked to said diaphragm so as to move said diaphragm.

7. A deposition apparatus comprising:

a positive displacement liquid-delivery apparatus comprising;

a positive displacement pump including a housing having a liquid-delivery chamber and a working space divided from said liquid-delivery chamber by a flexible diaphragm, and including a diaphragm driving unit linked to said diaphragm to discharge fluid from said liquid-delivery chamber by changing a volume of said liquid-delivery chamber; and

a differential pressure control unit for controlling a differential pressure between said liquid-delivery chamber and said working space so as to maintain the differential pressure between said liquid-delivery chamber and said working space at a constant value during a pumping operation of said positive displacement pump;

a vaporizer for vaporizing the fluid discharged from said positive displacement liquid-delivery apparatus; and

a deposition chamber in which thin films are deposited using the feed gas supplied from said vaporizer;

wherein said diaphragm driving unit of said positive displacement liquid-delivery apparatus is operable to change the volume of said liquid-delivery chamber while said differential pressure control unit maintains the differential pressure between said liquid-delivery chamber and said working space at the constant value.

8. A deposition apparatus as claimed in claim 7, wherein the differential pressure control unit comprises:

a differential pressure sensor for detecting the differential pressure between said liquid-delivery chamber and said working space, and for generating a differential pressure signal based on the detected differential pressure; and

a control valve for controlling a flow rate of the fluid discharged from said liquid-delivery chamber based on the differential pressure signal generated by said differential pressure sensor.

9. A deposition apparatus as claimed in claim 8, wherein said positive displacement liquid-delivery apparatus further comprises:

a flow sensor disposed on a discharge path from said positive displacement pump and operable to detect the flow rate of the fluid discharged from said liquid-delivery chamber, and to generate a flow signal based on the detected flow rate;

wherein said control valve is operable to control the flow rate of the fluid discharged from said liquid-delivery chamber based on the flow signal generated by said flow sensor when a pressure in said liquid-delivery chamber during the pumping operation exceeds a prescribed pressure value or when an absolute value of a rate of pressure variations exceeds a prescribed pressure variation value.

10. A deposition apparatus as claimed in claim 7, wherein said liquid-delivery chamber is arranged so as to achieve a required discharge flow volume of the fluid in one stroke.

11. A deposition apparatus as claimed in claim 7, wherein said positive displacement liquid-delivery apparatus further comprises a flow control unit including:

a flow sensor disposed on a discharge path from said positive displacement pump and operable to detect the flow rate of the fluid discharged from said liquid-delivery chamber, and to generate a flow signal based on the detected flow rate; and

a control valve for controlling a flow rate of the fluid discharged from said liquid-delivery chamber based on the flow signal generated by said flow sensor.

12. A deposition apparatus as claimed in claim 8, wherein said diaphragm driving unit of said positive displacement pump comprises:

a drive unit; and

a rod having a first end linked to said drive unit such that said drive unit is operable to move said rod along a longitudinal axis of said rod in either direction, and having a second end linked to said diaphragm so as to move said diaphragm.