U.S. patent application number 11/506401 was filed with the patent office on 2007-02-22 for piston-reciprocating gas compressor.
Invention is credited to Hiroshi Inoue, Akira Kawamoto.
Application Number | 20070041847 11/506401 |
Document ID | / |
Family ID | 37737454 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070041847 |
Kind Code |
A1 |
Inoue; Hiroshi ; et
al. |
February 22, 2007 |
Piston-reciprocating gas compressor
Abstract
A drive shaft is driven by an electric motor in a motor casing.
A crankshaft integrally connected with the drive shaft is provided
in a crankcase. A piston is reciprocated by the crankshaft in a
cylinder. A gas is introduced from the outside into the motor
casing and forwarded into the crankcase. The gas is further guided
into a space on the piston through a gas-guiding groove formed in
the inner circumference of the cylinder. The piston moves up to
compress the gas in the space while the piston closes the upper end
of the gas-guiding groove, so that the gas is discharged to the
outside.
Inventors: |
Inoue; Hiroshi;
(Yokohama-shi, JP) ; Kawamoto; Akira;
(Sagamihara-shi, JP) |
Correspondence
Address: |
DAVIS & BUJOLD, P.L.L.C.
112 PLEASANT STREET
CONCORD
NH
03301
US
|
Family ID: |
37737454 |
Appl. No.: |
11/506401 |
Filed: |
August 18, 2006 |
Current U.S.
Class: |
417/269 |
Current CPC
Class: |
F04B 39/0016 20130101;
F04B 35/04 20130101; F04B 39/066 20130101 |
Class at
Publication: |
417/269 |
International
Class: |
F04B 27/08 20060101
F04B027/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 2005 |
JP |
2005-238685 |
Claims
1. A piston-reciprocating gas compressor comprising: an electric
motor; a motor casing including the electric motor and having a
gas-introducing hole through which a gas is introduced from an
outside: a drive shaft driven by the electric motor and extending
in the motor casing; a crankshaft integrally connected to the drive
shaft; a crankcase including the crankshaft and having a
gas-guiding hole to allow the motor casing to communicate with the
crankcase; a piston reciprocated by the crankshaft; and a cylinder
including the piston and having a gas-guiding groove in a lower
part of an inner circumference to allow the crankcase to
communicate with a space on the piston in the cylinder when the
piston is in a lower position so that the gas in the crankcase is
guided into the space through the gas-guiding groove between an
outer circumference of the piston and the inner circumference of
the cylinder, an upper end of the gas-guiding groove being closed
when the piston moves up so that the gas in the space on the piston
is compressed and discharged from the cylinder.
2. The piston-reciprocating gas compressor according to claim 1
wherein the gas is discharged through a discharge check valve in a
wall of the cylinder.
Description
[0001] This application claims priority from Japanese Application
Serial No. 2005-238685 filed Aug. 19, 2005.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a piston-reciprocating gas
compressor compressing a gas by reciprocating a piston.
[0003] As shown in FIG. 2, a piston-reciprocating gas compressor is
known, in which a discharge check valve 23 and a suction check
valve 24 are provided at one side and the other side of a top wall
22 of a cylinder 21. On the discharge check valve 23 and suction
check valve 24, a suction chamber 26 having an inlet 25 and a
discharge chamber 28 having an outlet 27 are provided respectively.
In a crankcase 29 under the cylinder 21, a crankshaft 31 is
integrally connected to a drive shaft 30. A drive shaft 30 is
driven by an electric motor 32 outside the crankcase 29, so that a
piston 34 in the cylinder 21 is reciprocated by the crankshaft 31
via a piston rod 33. A gas such as N.sub.2 sucked from the inlet 25
is introduced into a space on the piston 34 via the suction check
valve 23, compressed and discharged via the discharge check valve
24 and outlet 27.
[0004] In such a piston-reciprocating gas compressor, with
reciprocating movement of the piston 34, the gas introduced into
the space on the piston 34 in the cylinder 21 is partially leaked
around the piston 34 to flow back into the crankcase 29 and is
released to air from a ventilating hole 35. If the gas is toxic, it
will cause environmental contamination.
[0005] In a booster-type compressor in which a compressed gas is
sucked and further compressed, a compression chamber is
decompressed in a sucking step during restarting or non-load
operation, so that a gas introduced into the crankcase 29 via the
ventilating hole 35 flows between the outer circumference of the
piston 34 and the inner circumference of the cylinder 21 into the
space on the piston 34 and is mixed with a gas from the inlet 25 to
make its concentration lower.
[0006] Furthermore, to cool the electric motor 32, it is necessary
to provide a ventilating hole 40 in the motor casing 36 and to
mount a blowing fan on the drive shaft 30 to carry out forced
cooling. Thus, it is not possible to seal the electric motor
completely thereby rendering noise to leak and/or making dusts in
air and solid components remain in each part of the electric motor
32 and motor casing 36.
[0007] In a booster-type compressor in which a gas is introduced
into a space on the piston 34 via the inlet 25 and suction check
valve 34, compressed and discharged from the outlet 27 via the
discharge check valve 24, torque fluctuation per one rotation
becomes larger to increase electric current value of the electric
motor 32 directly mounted to the crankcase 29.
[0008] To overcome the disadvantages in the conventional
piston-reciprocating gas compressor, the ventilating hole 35 of the
crankcase 29 is removed to seal the crankcase 29 and electric motor
32. If the crankcase 29 and electric motor 32 are sealed,
temperature of the inside of the crankcase 29 and electric motor 32
rises to cause damage to the bearing 35,36 and seal 37 of the drive
shaft 30 and crankshaft 31 resulting in deterioration or leakages
of oil to decrease the performance and durability of the
compressor.
SUMMARY OF THE INVENTION
[0009] In order to overcome the disadvantages in the prior art, it
is an object of the invention to provide a piston-reciprocating gas
compressor that overcomes the disadvantages involved by an electric
motor mounted outside a crankcase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The features and advantages of the invention will become
more apparent from the following description with respect to an
embodiment as shown in accompanying drawings wherein:
[0011] FIG. 1 is a vertical sectional view showing a gas compressor
according to the present invention; and
[0012] FIG. 2 is a vertical sectional view of a conventional gas
compressor.
DETAILED DESCRIPTION OF PREFERREN EMBODIMENT
[0013] FIG. 1 is an embodiment of a piston-reciprocating gas
compressor according to the present invention.
[0014] A discharge check valve 3 is provided in a top wall 2 of a
cylinder 1, and a discharge chamber 5 having an outlet 4 is formed
on the top wall 2. The lower end of the cylinder 1 is connected to
a sealed crankcase 6. A motor casing 8 having a gas-introducing
hole 7 at the end is connected to one side of the crankcase 6 via
gas-guiding holes 9,9.
[0015] A motor 10 is provided in the motor casing 8, and a drive
shaft 11 is integrally formed with a crankshaft 13 pivotally
mounted in bearings 12,12 in the crankcase 6.
[0016] The end of a piston rod 15 of a piston 14 in the cylinder 1
is pivotally mounted to the crankshaft 13 via a bearing 16.
[0017] There is formed a gas-guiding groove 17 in the inner surface
of the cylinder 1. The lower end of the gas-guiding groove 17
communicates with the inside of the crankcase 6. When the piston 14
is in the lowest position, the upper end of the gas-guiding groove
17 communicates with a space on the piston 14 in the cylinder 1,
while the upper end of the gas-guiding groove is closed by the
piston 14 and a piston ring as soon as the piston 14 moves up.
[0018] The discharge check valve 3 does not open by a compressed
gas in the crankcase 6, but is set to open when a gas in the space
in the cylinder 1 is compressed by moving up the piston 14.
[0019] The piston 14 is reciprocated by the drive shaft 11. Then an
ordinary pressure gas or a compressed gas such as N.sub.2 in the
crankcase 6 is forwarded to the space on the piston 14 via the
gas-guiding groove 17, compressed and discharged via the discharge
check valve 3 and a discharge hole 4.
[0020] Instead of the gas-guiding groove 17, an intake check valve
may be used in the piston 14.
[0021] The foregoing merely relate to an embodiment 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:
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