KR20180106713A - Reciprocating fluid compressing apparatus and method - Google Patents

Abstract

The present invention relates to a gas compressor, effectively providing lubricant oil free compressed gas, wherein lubricant oil can be prevented from being mixed with compressed gas generated in a cylinder. The gas compressor bypasses a portion of the compressed gas discharged through a discharge valve of a cylinder to supply the bypassing compressed gas between a cylinder inner wall and a piston outer circumferential surface or to supply compressed gas by using an additional compressed gas supply apparatus. Moreover, the gas compressor supplies the compressed gas more than inner pressure of the cylinder in the position that the compressed gas is injected into a labyrinth seal to effectively prevent gas to be compressed from leaking into a gap between the cylinder inner wall and the piston outer circumferential surface. Accordingly, the gas compressor can be used both for high-pressure and a general use.

Description

TECHNICAL FIELD [0001] The present invention relates to a reciprocating gas compression apparatus and a reciprocating gas compression apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating gas compression apparatus and method capable of efficiently obtaining a lubricant oil free compressed gas in which lubricating oil is not mixed in a compressed gas produced in a cylinder, And the compressed gas is supplied at a pressure higher than the internal pressure of the cylinder at the position where the compressed gas is injected into the labyrinth seal to effectively prevent the gas inside the cylinder from leaking due to the clearance between the cylinder inner wall and the outer peripheral surface of the piston And more particularly, to a reciprocating gas compression apparatus and method capable of performing reciprocating gas compression.

Generally, a compressor is a mechanical device for compressing a gas such as air or natural gas to increase the pressure. The mechanical energy is applied to the gas drawn from the outside to increase the mechanical energy of the gas, To obtain high pressure gas.

The reciprocating compressor compresses the gas while reciprocating the piston in the cylinder. 2) A rotary compressor (compressor) in which the rotor rotates inside the cylinder and compresses the gas a rotary compressor, 3) a screw compressor for compressing the gas by engagement of two rotors of female and male, 4) a centrifugal force of a high-speed rotating impeller, And centrifugal compressors that convert energy into pressure.

1 is a cross-sectional view illustrating a seal structure of a conventional oil-type reciprocating compressor.

1, a conventional reciprocating compressor has an O-ring 13 for sealing on the outer circumference of the piston 12 because the inner wall of the cylinder 11 and the outer circumferential face of the piston 12 are in contact with each other , Lubrication oil is essential for lubrication and friction reduction.

However, in the conventional oil type reciprocating compressor, there is a disadvantage that a part of the lubricating oil injected for lubricating and friction reduction is mixed into the compressed gas.

If the lubricating oil is mixed in the compressed gas, the quality of the compressed gas is deteriorated and it is not suitable for use in the semiconductor or precision machine manufacturing process, and the operation of removing the lubricating oil mixed through the separate filtering process must be performed separately There is a problem and there is a technical limitation that the lubricating oil that has already been mixed can not be completely removed even though the filtering process is carried out.

To solve this problem, contactless or oil-free sealing type compressors have been developed.

2 is a cross-sectional view illustrating a seal structure of a conventional non-contact type reciprocating compressor.

2, in the conventional reciprocating non-contact type compressor, a labyrinth seal 23 is formed on the inner wall of the cylinder 21 and on the outer periphery of the piston 22.

Since the inner wall of the cylinder 21 and the outer peripheral surface of the piston 22 do not contact each other, no lubricating oil is used. In the labyrinth seal structure, the pressure drops each time it passes through the labyrinth seal 23 on the inner wall of the cylinder, and when the pressure passes a certain distance, the pressure becomes zero, and the movement of the gas disappears.

However, in the conventional noncontact type reciprocating compressor, a leak of a gas to be compressed occurs due to a gap between the outer circumferential surface of the piston and the inner wall of the cylinder, thereby reducing pressure loss and efficiency. There is a limit that can only be used where it is needed.

Korean Patent Laid-Open Publication No. 10-2015-0003331

The present invention provides a compressed gas supply system that bypasses a portion of a compressed gas discharged through a discharge valve of a cylinder and supplies the compressed compressed gas between the inner wall of the cylinder and the outer circumferential surface of the piston or a separate compressed gas supply device, It is possible to effectively prevent the gas inside the cylinder from leaking due to the gap between the inner wall of the cylinder and the outer surface of the piston by supplying the compressed gas at a pressure higher than the internal pressure of the cylinder at the position where it is injected into the labyrinth seal, And it is an object of the present invention to provide a reciprocating gas compression apparatus and method.

In order to achieve the above-mentioned object, the reciprocating gas compression method of the present invention compresses and discharges a gas sucked while reciprocating a piston in a cylinder, and compresses and discharges the compressed gas between the inner wall of the cylinder formed on the outer circumferential surface of the piston and the outer circumferential surface of the piston The compression gas is supplied at a pressure higher than the internal pressure of the cylinder at a position where the compression gas is injected into the labyrinth seal, thereby effectively preventing leakage of the gas (cylinder internal gas) to be compressed into the gap between the inner wall of the cylinder and the outer peripheral surface of the piston.

The reciprocating gas compressor of the present invention comprises: a cylinder in which a suction valve for sucking a gas is formed at one side and a discharge valve for discharging gas at the other side; A piston reciprocating in the cylinder while compressing the gas sucked from the suction valve to generate a compressed gas, discharging the compressed gas to the discharge valve, and forming a labyrinth seal on the outer circumferential surface; A crank assembly connected to the piston rod of the piston to convert rotational motion of the motor into reciprocating movement of the piston; A compressed gas supply unit for supplying a high-pressure compressed gas between the inner wall of the cylinder and the outer surface of the piston so as to prevent leakage of gas to be compressed in the cylinder by a gap between the inner wall of the cylinder and the outer surface of the piston; And a compressed gas bypass line for bypassing a portion of the compressed gas discharged through the discharge valve to supply the compressed gas to the labyrinth seal.

The compressed gas supply unit may be installed in the compressed gas bypass line.

The compressed gas supplied between the inner cylinder wall and the piston outer circumferential surface can be in the range of 60 bar to 400 bar, and preferably in the range of 150 bar to 300 bar.

The pressure of the compressed gas supplied between the inner wall of the cylinder and the outer surface of the piston may be the same as the discharge pressure of the cylinder, for example, 300 bar.

Wherein a compressed gas injection hole is formed in a side surface of the cylinder to supply a compressed gas into the labyrinth seal in the compressed gas supply unit, a compressed gas receiving groove is formed on an outer peripheral surface of the piston, And the labyrinth seal may be formed on the lower side.

And the compression gas accommodating groove and the compressed gas injection hole are always kept in a communicated state between the top dead center and the bottom dead point of the piston when the piston reciprocates.

Wherein a gas recovery space is formed in a lower portion of the cylinder so that the compressed gas supplied from the compressed gas supply unit is collected downward through the clearance and a gas collected in the gas recovery space is introduced into the gas recovery space A gas discharge hole may be formed for discharging the gas to the outside.

The gas discharged from the gas discharge hole may be either recovered to the compressed gas supply unit or vented to the atmosphere.

Wherein the suction valve is opened by the gas suction pressure inside the cylinder when the piston operates in the bottom dead center direction and is closed by the gas compression force inside the cylinder when the piston is operated in the top dead center direction, The piston is closed by the gas suction pressure inside the cylinder when the piston operates in the bottom dead center direction and is opened by the gas compression force inside the cylinder when the piston is operated in the top dead center direction.

The technology of the present invention can be applied to all the gases of an air compressor or a natural gas compressor (CNG compressor), as well as to a gas whose purity of the medium to be compressed is nearly 100%.

As described above, according to the present invention, the compressed gas is supplied into the labyrinth seal formed on the outer peripheral surface of the piston, that is, between the inner cylinder wall and the outer peripheral surface of the piston, It is possible to effectively prevent leakage of gas to be compressed by a gap between the inner wall of the cylinder and the outer circumferential surface of the piston by supplying the pressure beyond the internal pressure,

Further, in the course of recovering the compressed gas supplied to the labyrinth seal to the gas recovery space, the oil used for lubrication of the piston rod due to the pressure of the compressed gas in the gas recovery space is prevented from flowing back into the cylinder, Can be increased.

1 is a cross-sectional view illustrating a seal structure of a conventional oil-type reciprocating compressor
2 is a cross-sectional view illustrating a seal structure of a conventional oil-free type reciprocating compressor
FIG. 3 is an overall schematic view showing a reciprocating gas compression apparatus according to a first embodiment of the present invention
4 is a view for explaining the inside of the cylinder and the compressed gas recovery space of Fig. 3
Fig. 5 is an outline drawing of Fig. 4
6 is a diagram showing a reciprocating gas compression apparatus according to a second embodiment of the present invention

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a reciprocating gas compression apparatus and method of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view for explaining the inside of the cylinder and the compressed gas recovery space of FIG. 3, and FIG. 5 is a cross-sectional view of the recessed portion of the reciprocating gas compression apparatus according to the first embodiment of the present invention. It is an excerpt.

3 and 5, the reciprocating gas compression method of the present invention compresses and discharges gas sucked while reciprocating the piston 120 in the cylinder 110, and compresses and discharges gas between the inner wall of the cylinder and the outer circumferential surface of the piston 120 The compressed gas is supplied into the labyrinth seal 122 formed on the outer circumferential surface of the piston 120 so that the compressed gas is supplied to the inside of the cylinder at a position where the compressed gas is injected into the labyrinth seal, It is possible to effectively prevent the gas to be compressed from leaking due to the clearance between the outer surfaces of the pistons.

The compressed gas supplied between the inner surface of the cylinder 110 and the outer surface of the piston 120 may range from 60 bar to 400 bar, preferably from 150 bar to 300 bar.

The reciprocating gas compression apparatus according to the first embodiment of the present invention bypasses a portion of the compressed gas discharged through the discharge valve 112 of the cylinder 110 and transfers the bypassed compressed gas to the labyrinth seal 122, It is a configuration to supply in.

A reciprocating gas compression apparatus 100 according to the first embodiment of the present invention includes a cylinder 110, a piston 120, a crank assembly 130, a compressed gas bypass line 140, and a compressed gas supply unit 150 .

The cylinder 110 has a suction valve 111 for sucking gas on one side thereof and a discharge valve 112 for discharging gas on the other side thereof.

The suction valve 111 is opened by the gas sucking pressure inside the cylinder 110 when the piston 120 operates in the bottom dead center direction and is opened when the piston 120 operates in the top dead center direction, It is closed by compressive force.

The discharge valve 112 is closed by the gas suction pressure inside the cylinder 110 when the piston 120 is operated in the bottom dead center direction and is closed by the gas inside the cylinder 110 when the piston 120 is operated in the top dead center direction. And is configured to be opened by a compressive force.

The piston 120 sucks gas from the suction valve 111 while reciprocating in the cylinder 110, compresses the sucked gas to generate a compressed gas, and discharges the compressed gas to the discharge valve 112 . A compression gas receiving groove 121 is formed on the outer circumferential surface of the piston 120 and a labyrinth seal 122 is formed on the upper and lower sides of the compressed gas receiving groove 121, respectively.

The crank assembly 130 is connected to the piston rod 125 of the piston 120 to convert the rotational motion of the motor (not shown) into the reciprocating motion of the piston 120. A connecting rod 132 is connected to the crankshaft 131 and a connecting rod 132 is connected to the piston rod 125. The connecting rod 132 is connected to the crankshaft 131,

The compressed gas bypass line 140 is installed to bypass a portion of the compressed gas discharged through the discharge valve 112 and supply it to the labyrinth seal 122.

The compressed gas supply unit 150 is provided with a labyrinth seal 150 for effectively preventing leakage of gas to be compressed inside the cylinder 110 by a gap between the inner wall of the cylinder 110 and the outer circumferential face of the piston 120 during gas compression, (122).

The compressed gas supply unit 150 includes a reservoir tank for maintaining the pressure of the compressed gas flowing through the compressed gas bypass line 140 at a high pressure, for example, about 300 bar.

On-off valves V1 and V2 are provided on the inlet side and the outlet side, respectively, with reference to the compressed gas supply unit 150. [

A compressed gas injection hole 113 is formed in a side surface of the cylinder 110 in order to supply the compressed gas into the labyrinth seal 122 in the compressed gas supply unit 150, It is preferable to maintain the communicating state of the valve body 121.

In other words, it is preferable that the compressed gas accommodation groove 122 and the compressed gas injection hole 113 are maintained in a communicated state when the piston 120 reciprocates between the top dead center and the bottom dead center of the piston 120 Do.

A gas recovery space 160 is formed in a lower portion of the cylinder 110 to collect the compressed gas supplied from the compressed gas supply unit 150 downward through a gland 163, A gas discharge hole 161 for discharging the gas collected in the gas recovery space 160 to the outside of the gas recovery space 160 is formed on the inner wall of the gas recovery space 160.

The gas discharged from the gas discharge hole 161 can be returned to the compressed gas supply unit 150 or vented into the atmosphere.

The bottom plate 165 of the gas recovery space 160 is provided with a bearing 166 for supporting the piston rod 125. The oil in the bearing 166 is supplied to the crank assembly 130 ).

In the reciprocating gas compression apparatus according to the first embodiment of the present invention constructed as described above, when the motor (not shown) is driven, the crank assembly 130 rotates the motor (not shown) .

The suction valve 111 is opened by the gas sucking pressure inside the cylinder 110 when the piston 120 operates in the bottom dead center direction and is opened when the piston 120 operates in the top dead center direction, It is closed by compressive force.

On the contrary, the discharge valve 112 is closed by the gas suction pressure inside the cylinder 110 when the piston 120 operates in the bottom dead center direction, and when the piston 120 operates in the top dead center direction, By the gas compression force of the gas.

The compressed gas is supplied to the compressed gas accommodating portion due to the opening and closing of the suction valve 111 and the discharge valve 112 and the reciprocating motion of the piston 120. [

The compressed gas supply unit 150 opens the on-off valve V1 to store a portion of the compressed gas flowing through the bypass line 140 therein to maintain the pressure at about 300 bar at all times.

The compressed gas supply unit 150 closes the on-off valve V1 and opens the on-off valve V2 to supply the compressed gas into the labyrinth seal 122 and into the compressed gas injection hole 113 of the cylinder 110 The compressed gas is supplied.

The gas introduced through the compressed gas injection hole 113 is supplied into the compressed gas accommodating groove 121. It is preferable that the compressed gas injection hole 113 and the compressed gas receiving groove 121 are maintained in a communicated state because the efficiency of gas leakage prevention can be enhanced.

In other words, when the piston 120 reciprocates between the top dead center and the bottom dead center of the piston 120, the compressed gas accommodation groove 122 and the compressed gas injection hole 113 are always kept in a communicated state desirable.

Since the gas introduced through the compressed gas injection hole 113 into the labyrinth seal 122 is supplied even if the compressed gas injection hole 113 and the compressed gas receiving groove 121 are not communicated with each other, Can be prevented.

The compressed gas is supplied into the labyrinth seal 122 formed between the outer peripheral surface of the piston 120 and the inner wall of the cylinder so that gas to be compressed leaks into a gap between the inner wall of the cylinder 110 and the outer peripheral surface of the piston 120 It is possible to effectively prevent the leakage of the gas to be compressed by supplying the pressure equal to the discharge pressure of the cylinder 110 or the internal pressure of the cylinder at the position to be injected into the labyrinth seal 122 so that the gas to be compressed flows into the gap between the inner wall of the cylinder and the outer peripheral surface of the piston Can be effectively prevented.

Here, since the pressure of the compressed gas injected into the labyrinth seal 122 becomes a pressure drop in accordance with the distance from the cylinder discharge portion to the portion injected into the actual labyrinth seal 122, It is smaller than pressure.

Therefore, the same pressure as the discharge pressure does not necessarily mean the same numerical pressure exactly, but also means a concept including a pressure range including a predetermined pressure drop due to piping or other factors, and a pressure range which varies to an approximate degree.

5, the pressure of the compressed gas beyond the cylinder internal pressure at the position where it is injected into the labyrinth seal 122 is supplied to the labyrinth seal 122 at the compression stroke (top dead center position) of the piston 120, It is necessary to set the pressure to a level at which the leaking gas can be blocked.

For example, when the discharge pressure of the cylinder is 300 bar, the pressure drop is gradually increased to about 290 bar, 280 bar, and 250 bar according to the distance from the cylinder discharge portion to the portion to be injected into the actual labyrinth seal 122, The pressure of the compressed gas above the internal pressure of the cylinder at the position injected into the labyrinth seal 122 is at least 250 bar.

In addition, the compressed gas in the compressed gas accommodation groove 121 moves downward and flows into the gas recovery space 160.

The gas in the gas recovery space 160 is discharged to the outside through the gas discharge hole 161 when the gas is introduced into the gas recovery space 160 at a predetermined pressure or more, The gas pressure is always constant.

The gas discharged from the gas discharge hole 161 can be returned to the compressed gas supply unit 150 or discharged to the atmosphere.

The bottom plate 165 of the gas recovery space 160 is provided with a bearing 166 for supporting the piston rod 125. The oil in the bearing 166 is supplied to the crank assembly 130 So that oil leakage does not occur.

6 is a configuration diagram illustrating a reciprocating gas compression apparatus according to a second embodiment of the present invention.

Referring to FIG. 6, the reciprocating gas compression apparatus according to the second embodiment of the present invention includes a reciprocating gas compression apparatus according to the first embodiment of the present invention, except for the compressed gas supply apparatus 250 And therefore, the same reference numerals are assigned to the same components, and a detailed description thereof will be omitted.

The reciprocating gas compression apparatus according to the second embodiment of the present invention does not bypass a portion of the compressed gas discharged through the discharge valve 112 of the cylinder 110 but uses a separate compressed gas supply device 250 And into the seal 122.

The reciprocating gas compression apparatus according to the second embodiment of the present invention can freely control the supply of compressed gas by separately configuring the compressed gas supply apparatus 250 without connecting it to the compressed gas bypass line 140. [

As described above, in the present invention, a high-pressure compressed fluid or a compression gas equivalent to the cylinder discharge pressure is supplied between a cylinder inner wall and an outer peripheral surface of the piston in a labyrinth seal formed on the outer peripheral surface of the piston, The gap between the inner wall and the outer circumferential surface of the piston effectively prevents leakage of the gas to be compressed, which is advantageous in that it can be used generally at low pressure and high pressure.

Further, in the course of recovering the compressed gas supplied to the labyrinth seal to the gas recovery space, the oil used for lubrication of the piston rod due to the pressure of the compressed gas in the gas recovery space is prevented from flowing back into the cylinder, Can be increased.

110: Cylinder
111: Suction valve
112: discharge valve
113: Compressed gas injection hole
120: piston
121: Compressed gas receiving groove
122: Labyrinth seal
125: Piston rod
130: Crank assembly
131: Crankshaft
132: connecting rod
140: Compressed gas bypass line
150: Compressed gas supply unit
160: gas recovery space
161: gas discharge hole
163: gland
166: Bearings
250: Compressed gas supply unit
V1, V2: opening / closing valve

Claims (16)

A cylinder in which a suction valve for sucking a gas is formed at one side and a discharge valve for discharging gas at the other side is formed;
A piston reciprocating in the cylinder while compressing the gas sucked from the suction valve to generate a compressed gas, discharging the compressed gas to the discharge valve, and forming a labyrinth seal on an outer circumferential surface thereof;
A crank assembly connected to the piston rod of the piston to convert rotational motion of the motor into reciprocating movement of the piston; And
A pressurized gas supply unit for supplying a pressurized gas between the inner cylinder wall and the outer circumferential surface of the piston so as to prevent leakage of gas to be compressed in the cylinder by a gap between the inner cylinder wall and the outer circumferential surface of the piston; And the reciprocating gas compression device. The method according to claim 1,
Wherein the compressed gas pressure supplied between the inner cylinder wall and the piston outer circumferential surface ranges from 60 bar to 400 bar. The method according to claim 1,
Wherein the pressure of the compressed gas supplied between the inner wall of the cylinder and the outer surface of the piston is equal to the pressure of discharge of the cylinder. The method according to claim 1,
Wherein a pressure of the compressed gas supplied between the inner wall of the cylinder and the outer surface of the piston is equal to or higher than the pressure inside the cylinder at a position to be injected into the labyrinth seal. The method according to claim 1,
Further comprising a compressed gas bypass line for bypassing a portion of the compressed gas discharged through the discharge valve to supply the compressed gas to the labyrinth seal. The method of claim 5,
And the compressed gas supply unit is installed in the compressed gas bypass line. The method according to claim 1,
Wherein a compressed gas injection hole is formed in a side surface of the cylinder to supply a compressed gas into the labyrinth seal in the compressed gas supply unit, a compressed gas receiving groove is formed on an outer peripheral surface of the piston, And the labyrinth seal is formed on a lower side of the reciprocating gas compression device. The method of claim 7,
Wherein when the piston reciprocates between a top dead center and a bottom dead point of the piston, the compressed gas accommodation groove and the compressed gas injection hole are maintained in a communicated state. The method according to claim 1,
Wherein a gas recovery space is formed in a lower portion of the cylinder so that the compressed gas supplied from the compressed gas supply unit is collected downward through the clearance and a gas collected in the gas recovery space is introduced into the gas recovery space And a gas discharge hole for discharging the gas to the outside of the gas discharge hole. The method of claim 9,
Wherein the gas introduced into the gas recovery space is automatically discharged through the gas discharge hole when the pressure exceeds a predetermined pressure. The method according to claim 1,
Wherein the gas discharged from the gas discharge hole is either recovered to the compressed gas supply unit or vented to the atmosphere. The method according to claim 1,
Wherein the suction valve is opened by the gas suction pressure inside the cylinder when the piston operates in the bottom dead center direction and is closed by the gas compression force inside the cylinder when the piston is operated in the top dead center direction,
And the discharge valve is configured to be closed by the gas suction pressure inside the cylinder when the piston operates in the bottom dead center direction and to be opened by the gas compression force inside the cylinder when the piston operates in the top dead center direction. Of the reciprocating gas compression device. A compressed gas is supplied between the inner wall of the cylinder and the outer circumferential face of the piston so that the compressed gas inside the cylinder is discharged through the gap between the inner wall of the cylinder and the outer circumferential surface of the piston, Thereby preventing leakage of the gas. 14. The method of claim 13,
Wherein the pressure of the compressed gas supplied between the inner wall of the cylinder and the outer circumferential surface of the piston is set to be from 60 bar to 400 bar. 14. The method of claim 13,
Wherein the pressure of the compressed gas supplied between the inner wall of the cylinder and the outer surface of the piston is set to a pressure equal to the discharge pressure of the cylinder. 14. The method of claim 13,
And the pressure of the compressed gas supplied between the inner wall of the cylinder and the outer surface of the piston is set to be equal to or higher than the pressure inside the cylinder at a position to be injected into the labyrinth seal.

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