U.S. patent application number 11/421567 was filed with the patent office on 2006-12-07 for method of feeding an inert gas and a system therefor.
This patent application is currently assigned to ANEST IWATA CORPORATION. Invention is credited to TOSHIO IIDA, YOSUKE OGAWA.
Application Number | 20060275141 11/421567 |
Document ID | / |
Family ID | 37483841 |
Filed Date | 2006-12-07 |
United States Patent
Application |
20060275141 |
Kind Code |
A1 |
OGAWA; YOSUKE ; et
al. |
December 7, 2006 |
METHOD OF FEEDING AN INERT GAS AND A SYSTEM THEREFOR
Abstract
An inert gas is fed from an inert gas source to a
piston-reciprocating compressor and compressed therein. The
compressed gas is sent to a high-pressure storage tank. Pressure of
the gas in the high-pressure storage tank is detected. When it
reaches an upper limit, the piston-reciprocating compressor is
stopped by a controller. At the same time, the gas is not fed from
the inert gas source into the piston-reciprocating compressor and
the gas from the compressor is released to outside. Meanwhile, when
the pressure of the gas in the high-pressure storage tank reaches
to a lower limit, the compressor starts. At the same time, the
inert gas source is allowed to communicate with the compressor, and
the gas which reaches to a desired density after the gas is
released is sent from the compressor to the tank.
Inventors: |
OGAWA; YOSUKE;
(YOKOHAMA-SHI, JP) ; IIDA; TOSHIO; (YOKOHAMA-SHI,
JP) |
Correspondence
Address: |
MCKEE, VOORHEES & SEASE, P.L.C.
801 GRAND AVENUE
SUITE 3200
DES MOINES
IA
50309-2721
US
|
Assignee: |
ANEST IWATA CORPORATION
3176, Shinyoshida-cho Kohoku-ku, Yokohama-shi, Kanagawa
YOKOHAMA-SHI
JP
|
Family ID: |
37483841 |
Appl. No.: |
11/421567 |
Filed: |
June 1, 2006 |
Current U.S.
Class: |
417/53 |
Current CPC
Class: |
F04B 49/03 20130101;
F04B 41/02 20130101; F04B 49/022 20130101 |
Class at
Publication: |
417/053 |
International
Class: |
F04B 49/06 20060101
F04B049/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2005 |
JP |
2005-164130 |
Claims
1. A method of feeding an inert gas, comprising the steps of:
feeding the inert gas from an inert gas source to a
piston-reciprocating compressor; compressing the gas in the
piston-reciprocating compressor; sending the compressed gas to a
high-pressure storage tank; detecting pressure of the gas in the
high-pressure storage tank when the pressure reaches an upper
limit, to stop the piston-reciprocating compressor and feed of the
inert gas into the piston-reciprocating compressor while the gas
from the piston-reciprocating compressor is released to outside;
and detecting pressure of the gas in the high-pressure storage tank
when the pressure reaches to a lower limit, to start the
piston-reciprocating compressor and to allow the inert gas source
to communicate with the piston-reciprocating compressor while the
gas is supplied from the piston-reciprocating compressor into the
high-pressure storage tank when the gas reaches a desired density
after the gas is released.
2. A method according to claim 1 wherein the inert gas comprises
N.sub.2.
3. A high-pressure inert gas feeding system comprising: an inert
gas source feeding an inert gas; a sucking conduit having a supply
valve and connected to the inert gas source; a piston-reciprocating
compressor having an inlet and an outlet, the inlet being connected
to the sucking conduit, said compressor compressing the inert gas;
a release conduit connected to the outlet of the
piston-reciprocating compressor and having a relief valve; a
high-pressure storage tank connected to the release conduit and
receiving the high-pressure inert gas; and a controller connected
to the high-pressure storage tank, the supply valve of the sucking
conduit, the piston-reciprocating compressor and the relief valve
of the release conduit, said controller closing the supply valve,
stopping the piston-reciprocating compressor and opening the relief
valve to allow the gas to flow to outside when the pressure of the
gas in the high-pressure storage tank reaches an upper limit, while
said controller opens the supply valve, starting the
piston-reciprocating compressor and shutting the relief valve after
density of the gas reaches a desired level to allow the release
conduit to communicate with the high-pressure storage tank when the
pressure of the gas in the high-pressure storage tank reaches a
lower limit.
4. A system according to claim 3 wherein the inert gas comprises
N.sub.2.
5. A system according to claim 3 wherein the relief valve comprises
a two-way electromagnetic valve, said system further comprising a
check valve in the release conduit between two-way electromagnetic
valve and the high-pressure storage tank.
6. A system according to claim 3 wherein the relief valve comprises
a three-way electromagnetic valve.
7. A system according to claim 3 wherein a pressure switch is
connected to the high-pressure storage tank to detect the pressure
of the gas in the high-pressure storage tank to send it to the
controller.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method of compressing an
inert gas sent from an inert gas source by a piston-reciprocating
compressor and a system therefor.
[0002] An inert gas such as N.sub.2 gas in a cylinder or produced
in a N.sub.2 gas generator is compressed by a booster compressor
and forwarded to a high-pressure storage tank or part for use.
[0003] An ordinary piston-reciprocating compressor is generally
employed as a booster compressor.
[0004] An inert gas is compressed by a piston-reciprocating
compressor. When a supply valve between the inert gas source and
the compressor is closed, pressure of a gas in a compression
chamber on a piston becomes less than atmospheric pressure, so that
air in a crank case under the piston likely invades into the
compression chamber through the outer circumferential surface of
the piston.
[0005] The inert gas is diluted by air, so that the density of the
inert gas in the compression chamber is reduced.
[0006] To prevent such state, the supply valve is left open to let
the inert gas source to communicate with the compression chamber
even when the compressor stops, so that the compression chamber of
the compressor does not become negative pressure.
[0007] However, in this case, a compressed gas in the compression
chamber leaks into the crank case on the outer circumferential
surface of the piston and is uselessly lost.
SUMMARY OF THE INVENTION
[0008] In view of the disadvantages above, it is an object of the
invention to provide a method of preventing density of an inert gas
in a high-pressure storage tank from lowering without losing the
inert gas and a system therefor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The features and advantages will become more apparent from
the following description with respect to embodiments as shown in
accompanying drawings wherein:
[0010] FIG. 1 is a diagram showing one embodiment of the present
invention; and
[0011] FIG. 2 is a diagram showing another embodiment of the
present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0012] In an inert gas source 1 such as an inert gas generator of
N.sub.2 gas or an inert gas cylinder which is filled with N.sub.2
under pressure, a sucking conduit 3 from an outlet hole 2 is
connected to an inlet 10 of a piston-reciprocating compressor 9
having a piston 8 which reciprocates in a cylinder by a motor, via
a supply valve 5 such as a two-way electromagnetic valve.
[0013] A release conduit 12 from an outlet 11 of the
piston-reciprocating compressor 9 is connected to a high-pressure
storage tank 14 via a check valve 13. Between the outlet 11 and the
check valve 13, a relief valve such as a two-way electromagnetic
valve 16 is connected to the conduit 12.
[0014] A pressure switch 23 of the high-pressure storage tank 14 is
connected to a controller 22 via a connecting line 24.
[0015] A discharge valve 26 is connected to a discharge hole 25 of
the high-pressure storage tank 14. To fill the high-pressure
storage tank 14 with an inert gas, the supply valve 5 is opened
with instructions from the controller 22, the relief valve 16 is
closed after opening during a certain time, and the piston 8 is
reciprocated in the piston-reciprocating compressor 9 by the motor
6.
[0016] The inert gas from the inert gas source 1 via the sucking
conduit 3 is compressed by the piston-reciprocating compressor 9
and forwarded to the high-pressure storage tank 14 via the check
valve 13. When pressure in the high-pressure storage tank 14
reaches an upper limit, the pressure switch 23 detects it. The
controller 22 instructs the supply valve 5 to close and to stop the
motor 6 to allow the piston-reciprocating compressor 9 to stop.
[0017] There is a little time lag between closing of the supply
valve 5 and full stop of the piston-reciprocating compressor 9.
During the time lag, a compression chamber on the piston 8 of the
piston-reciprocating compressor 9 is decompressed to allow air to
come into the compression chamber during a sucking stroke where the
piston goes down. So air is mixed with the inert gas in the
compression chamber and the sucking conduit 3, so that the density
of the gas is reduced.
[0018] In this state, when the piston-reciprocating compressor 9 is
operated again, density-reduced inert gas is sent to the
high-pressure storage tank 14 within the time for recompression. So
at the same time with or right after the recompression of the
piston-reciprocating compressor 9, the supply valve 5 is opened by
the instructions of the controller, so that high-density inert gas
in the inert gas source 1 is sent to the piston-reciprocating
compressor 9 and low-density inert gas in the release conduit 12 is
released via the relief valve 16.
[0019] The low-density inert gas in the release conduit 12 is
released for certain time. Thus, released inert gas from the
piston-reciprocating compressor 9 becomes more than a certain
density to make the controller 22 instruct to allow the relief
valve 16 to close.
[0020] Hereinafter, the piston-reciprocating compressor 9 does not
suck external air, but allows high-density inert gas from the inert
gas source 1 to go to the high-pressure storage tank 14 via the
check valve 13.
[0021] When an upper limit of pressure of inert gas in the
high-pressure storage tank 14 is detected by the pressure switch
23, the supply valve 5 is allowed to close via the controller 22
and the motor 6 is stopped to allow the piston 8 to stop.
[0022] FIG. 2 shows another embodiment of the present invention, in
which a three-way electromagnetic valve 28 is provided instead of
the two-way electromagnetic valve 16 and the check valve 13 in FIG.
1.
[0023] To compress an inert gas in a piston-reciprocating
compressor 9, a supply valve 5 in a sucking conduit 3 is opened and
the three-way electromagnetic valve 28 of a release conduit 12 is
opened for a certain time, and then closed.
[0024] When the pressure in a storage tank 14 reaches a certain
level, the piston-reciprocating compressor 9 is stopped and a
supply valve 5 is closed by a controller 22. The three-way
electromagnetic valve 28 is still opened.
[0025] When the piston-reciprocating compressor 9 starts to
compress a gas again, the supply valve 5 is opened and the
three-way electromagnetic valve 28 is opened, so that low-density
inert gas in the sucking conduit 3 and the compression chamber is
released from the release conduit. When the density of the inert
gas becomes a certain level, release is stopped by switching the
three-way electromagnetic valve 28 to allow it to communicate with
the storage tank 14.
[0026] The foregoing merely relates to embodiments of the
invention. Various changes and modifications may be made by a
person skilled in the art without departing from the scope of
claims wherein:
* * * * *