JP2006152975A - Reciprocating compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a hydrogen compressor of small capacity and high pressure plunger type for a hydrogen filling station. <P>SOLUTION: A reciprocating compressor 50 has a plurality of compressing stages 3, 4 and its final compressing stage 4 has a plunger 14 and a cylinder 16 housing this plunger. A discharge pressure of the compressor exceeds 40 MPa. The final compressing stage can use a lubricating oil 18 for a sealing means 16 for sealing a leakage between the plunger and the cylinder. Filtering equipment 10, having a plurality of filter means 10a-10c for removing oil component in a discharge gas discharged from the final compressing stage, is arranged at a downstream of the final compressing stage. The filter means has a bottle casing and a lid flange covering this bottle casing. An inlet portion and an outlet portion of the discharge gas are formed in the lid flange, and a multiplex element, formed by winding a filter element made from micro glass fiber in a multiplex manner, is housed inside the bottle casing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reciprocating compressor, and more particularly to a reciprocating compressor having a discharge pressure exceeding 40 MPa.

  Conventional examples of filter means for removing oil in discharge gas discharged from a reciprocating compressor are described in Patent Document 1 and Patent Document 2. In the air filter described in Patent Document 1, in order to reliably remove moisture and oil contained in the compressed air, the primary flow path in the primary port that guides air and the secondary in the secondary port A filter element is arranged between the side flow paths. The filter element is formed with a large number of porous hollow fibers aligned on the opening side, and the opening of the filter element faces the secondary channel.

  Further, in the oil separator described in Patent Document 2, in order to improve the maintenance performance and the oil separation performance, the oil separator is formed by a vertically disposed pipe member and an upper opening end of the pipe member. An element pipe seat that opens at the center and is connected to the gas outflow pipe is disposed at a slightly rear position. The element pipe seat is held on the bottom plate member connected to the pipe member, and the oil separation element is arranged between the element pipe seat and the pipe member. Furthermore, the upper half of the oil separation element protruding from the pipe member is covered with a casing.

  On the other hand, Non-Patent Document 1 describes an example of a conventional reciprocating compressor. In the diaphragm compressor described in this document, the working gas is compressed by introducing the working gas into a compression space partitioned by a diaphragm, which is a flexible film, and compressing and deforming the diaphragm with the pressure of the lubricating oil. This prevents the lubricating oil from being mixed into the working gas, thereby realizing a complete oil-free compressor.

JP-A-6-315615 JP 2001-263872 A Taisan Corporation Diaphragm Compressor Catalog, June 1982

  The oil separation means described in Patent Document 1 or 2 uses a filter element for oil separation as in the present invention, but it is sufficient that the pressure of the gas discharged from the compressor is 40 MPa or more. Is not considered. That is, since the pressure of the gas discharged from the compression unit is 40 MPa or more, the gas having a pressure of about 40 MPa also flows into the oil separation means. If it is made to withstand this pressure, the oil separating means will be enlarged.

  On the other hand, in the compressor described in Non-Patent Document 1, the diaphragm may be damaged due to fatigue due to long-term use. If the diaphragm breaks, a large amount of lubricating oil enters the process line or the working gas is ejected to the atmosphere. Further, the demand for increasing the discharge capacity of the compressor and the demand for higher pressure can be dealt with by increasing the diaphragm, but the displacement of the diaphragm increases and the fatigue life is reduced. In this case, the frequency of diaphragm replacement increases.

  The present invention has been made in view of the above problems of the prior art, and an object thereof is to realize a small capacity high pressure plunger type hydrogen compressor for a hydrogen supply station. Another object of the present invention is to reduce the oil content in the discharge gas as much as possible.

  A feature of the present invention that achieves the above object is that, in a multi-stage reciprocating compressor having a plurality of compression stages and having a discharge pressure exceeding 40 MPa, filter means for removing oil in the discharge gas discharged from the final compression stage The filter means is provided downstream of the final compression stage, and the filter means has a bottle case and a lid flange that covers the bottle case, and forms an inlet portion and an outlet portion of the discharge gas in the lid flange. The case contains a multi-element formed by wrapping a filter element made of microglass fiber.

  In this feature, the multiplex element has an inner element and an outer element, and a gap is preferably formed between the inner element and the outer element, and is discharged to the filter means from the inner periphery side to the outer periphery side of the multiplex element. It is preferable to form a flow path through which the gas moves. The second filter means is connected to the downstream side of the filter means, and the second filter means is a bottle case, a lid flange that covers the bottle case, and a microglass fiber filter accommodated in the bottle case. It is desirable to have an element, and more preferably, the third filter means is connected further downstream of the second filter means, and the third filter means includes a bottle case, a lid flange that covers the bottle case, And an activated carbon filter element housed in a bottle case.

  Another feature of the present invention that achieves the above object is that, in a multistage reciprocating compressor having a discharge pressure exceeding 40 MPa, the filter means for removing oil in the discharge gas discharged from the final compression stage is a downstream part of the final compression stage. The filter means includes a bottle case, a lid flange that covers the bottle case and is formed with an inlet portion and an outlet portion of discharge gas, and a cylindrical shape that is accommodated in the bottle case and formed in multiple layers. Filter element, a seat plate that holds one end of the cylindrical filter element in the axial direction, a clamping bolt that is inserted into the center of the filter element and clamps the filter element together with the seat plate and the lid flange, and tightening The outer periphery of the bolt includes a spring disposed between the tightening portion of the tightening bolt and the seat plate. In this feature, it is preferable to form a discharge gas passage between the innermost side of the filter element and the fastening bolt. In addition, any of the above features is suitable when hydrogen gas is used as the working gas.

  According to the present invention, in the reciprocating compressor having a discharge pressure of 40 MPa or more, the filter means containing the multilayered micro glass fiber filter elements is provided on the downstream side of the final stage, so that the oil content contained in the discharge gas is reduced. Since it can be reduced as much as possible, the reliability and safety of the reciprocating compressor is improved. As a result, a plunger type hydrogen compressor having a discharge pressure of 40 MPa or more can be realized.

The discharge pressure of the reciprocating compressor according to the present invention exceeds 40 MPa. This is because it is used to supply compressed hydrogen used in fuel cell vehicles. The following points need to be taken into account when using a large ultrahigh pressure reciprocating compressor for a fuel cell vehicle.
(1) Miniaturization and optimal structure considering economy
(2) Longer service life of parts
(3) Reduction of oil mist In a high-pressure hydrogen compressor used in a hydrogen supply station, unless the replacement period of consumable parts is at least one year, it becomes difficult to maintain the station due to frequent stoppages. Therefore, parts that can be used continuously without requiring maintenance and inspection are required. Further, in the compressed hydrogen gas used by the hydrogen fuel cell vehicle, if the concentration of the oil mist content is not less than the specified value, a problem occurs in the fuel cell unit, which may cause the vehicle to stop operating. Therefore, it is desired to reduce the content of oil mistakes as much as possible.

  An embodiment of the present invention made under such a problem will be described below with reference to the drawings. FIG. 1 is a block diagram of a plunger type small capacity high pressure compressor system. In the present embodiment, in order to simplify the description, the compressor is a two-stage plunger type compressor. In the first-stage compression stage 3, the plunger 13 is accommodated in the cylinder 3a, and in the second-stage compression stage 4, the plunger 14 is accommodated in the cylinder 4a. Plunger 13 and plunger 14 are arranged on the same axis.

  Shafts 13 a and 14 a are connected to the plungers 13 and 14, and the motor 12 connected to the crankshaft 42 drives these shafts 13 a and 14 a. Thereby, the rotational motion is converted into a reciprocating motion, and the working gas in the compression chamber formed between the tips of the plungers 13 and 14 and the cylinders 3a and 4a is compressed.

  The working gas 1 passes through a first-stage suction line 2 from a gas supply facility (not shown), flows into the compressor from the suction port 3b of the first-stage compression stage 3, and is compressed. The compressed working gas is discharged from the discharge port 3 c of the first-stage compression stage 3 and led to the intercooler 6 through the pipe 5. The working gas guided and cooled by the intercooler 6 is guided to the suction port 4b of the two-stage compression stage 4 through the two-stage suction line 7, and the pressure is further increased to 40 MPa or more. The working gas that has reached a high pressure is sent to the aftercooler 9 from the discharge port 4c of the two-stage compression stage 4 and cooled. The working gas cooled by the aftercooler 9 is sent to the filter equipment 10, and the lubricating oil or the like in the working gas is filtered and sent to the demand source.

  Here, each compression stage 3, 4 is provided with sealing means for preventing the compressed gas from leaking out of the machine and sealing means for preventing the lubricating oil from leaking into the compressed gas. In the single-stage compressor, a laminated rod packing 15 is provided on the cross head 41 side of the plunger 12 in order to prevent the working gas from leaking to the atmosphere side. Similarly, in order to prevent the working gas from leaking to the atmosphere side, a laminated rod packing 16 is provided on the cross head 41 side of the plunger 14 of the two-stage compressor 4.

  A small amount of sealing oil is supplied to the rod packings 15 and 16. Therefore, an oil supply hole 17 that communicates with the rod packing 15 is formed on the side of the cylinder 3a, and an oil supply hole 18 that communicates with the rod packing 16 is formed on the side of the cylinder 4a in a substantially radial direction. Since a part of the oil is mixed in the compressed hydrogen, which is the working gas, the oil mist is removed by the filter equipment 10 provided at the outlet of the compressor 50 so that the amount of oil mixed is less than the allowable value.

  Details of the filter facility 10 will be described with reference to FIGS. 2 and 3. FIG. 2 is a longitudinal sectional view of the primary filter 10a included in the filter facility 10, and is a filter located on the most upstream side. In the primary filter 10a, a bottle case 21 that has a flange portion 21a on the upper surface and is formed in a hollow shape, and a flange lid 22 that is flange-coupled to the flange portion 21a of the bottle case 21 form a pressure-resistant container. Flange portions 21a and 22a of the bottle case 21 and the flange lid 22 are provided at a plurality of locations in the circumferential direction, and are fastened by implantation bolts 29 and nuts 29b implanted in the bottle case 21.

  An inlet 23 for compressed hydrogen gas, which is a working gas, is formed on the side surface of the flange lid 22, and a flow path 23 b that extends inward in the radial direction and then downwards at a substantially central portion communicates with the inlet 23. Yes. A compressed hydrogen gas outlet 24 is formed at a slightly eccentric position in the center of the flange lid 22. The outlet 24 is connected to a flow path 24 b communicating with the hollow portion 21 c of the bottle case 21.

  On the lower surface side of the flange lid 22, the central portion 22 c protrudes downward to form a pedestal for the filter element 20. The filter element 20 has a receiving seat 27 formed with a bolt holding portion 27b extending vertically in the center of the disc-shaped receiving surface, and a flow path formed in the element lid 22 by fitting with the bolt holding portion of the receiving seat 27. A bolt 28 implanted in the element lid 22, an upper seat 27 b facing the seat 27 and attached to the central portion 22 c of the flange lid 22, and sandwiched between the seat 27 and the upper seat, The inner element 25 is disposed on the outer element 26, the outer element 26 is disposed on the outer side of the inner element 25, and a nut that holds the receiving seat 27 on the bolt 2828b. At the bottom of the bottle case 21, a discharge channel 30b for discharging a drain mainly composed of oil is formed, and a drain opening 30 is formed at the end of the channel 30b. A drain pipe (not shown) is connected to the drain opening 30.

  The portion of the bolt 28 located in the vertical portion of the flow path 23b is disposed so as to be coaxial with the flow path 23b. A slight gap δ is formed between the inner element 25 and the outer element 26. In the primary filter 10a formed in this way, the compressed hydrogen gas containing a slight amount of oil flowing in from the inlet 23 flows down the flow path 23b along the outer peripheral surface of the bolt 28, and between the upper receiving seat 27b and the receiving seat 27. The flow direction is changed radially outward and passes through the inner element 25 and then the outer element 26.

  The periphery of the outer element 26 is a hollow portion 21c of the bottle case 21, and the compressed hydrogen gas flowing out into the hollow portion 21c is sent to the secondary filter 10b disposed downstream from the outlet 24 via the flow path 24b. Since the secondary filter 10b has the same configuration as the primary filter 10a, the details are omitted. As the material for the inner element and the outer element, a micro glass fiber coreless element bonded with a fluorocarbon resin is used. When a micro glass fiber element is used, the oil component separated by the filter part is separated from the element by gravity without permeating the filter. And the inside of the bottle case 21 is dripped and collected in the bottom part of the bottle case 21, and is collect | recovered from the drain opening 30 provided in the lower part after that. Therefore, element replacement becomes unnecessary and oil can be reliably recovered.

  A tertiary filter 10c whose longitudinal sectional view is shown in FIG. 3 is arranged downstream of the secondary filter 10b. The tertiary filter 10c also constitutes a pressure vessel by fastening the bottle case 31 and the flange lid 32 with fastening bolts 38. The flange lid 32 has substantially the same configuration as the flange lid 21 of the primary filter 10a, but the shape of the lower protrusion 32b is different. Since the activated carbon filter 35 is used in the tertiary filter 10c, the I-shaped cross section is formed so that the protruding portion 32b can hold the activated carbon filter 35, and a holding portion is formed at the lower end portion of the I-shaped outer edge. Yes.

  The flange lid 32 is formed with a gas inlet 33, an L-shaped channel 33 b communicating with the inlet 33, an outlet 34 and a channel 34 b communicating with the outlet 34. Similar to the primary filter 10a, a bolt 37 is attached concentrically with a flow path 33b formed in the flange lid 32, and this bolt 37 is fitted to a receiving seat 36 disposed in the lower part. The activated carbon filter 35 is held between the upper surface of the receiving seat 36 and the lower surface of the protruding portion 32 b of the flange lid 32. The activated carbon filter 35 is obtained by mixing activated carbon with a nonwoven fabric to form a hollow cylinder.

  An opening 39 is formed at the bottom of the bottle case 31 and communicates with the bottom surface of the hollow portion of the bottle case 31. From this opening 39 part, the oil component transmitted through the bolt 37 and separated and stored by the activated carbon filter 35 is discharged as a drain. On the other hand, the compressed hydrogen gas flows into the activated carbon filter 35 along the peripheral surface of the bolt 37 and changes the flow direction in the radial direction of the filter 35 in the filter 35. Then, after passing through the filter 35, it reaches the outlet 34 through the flow path 34 b in the flange lid 22.

  According to this embodiment, a micro glass fiber filter is provided on the upstream side of the filter using activated carbon, and most of the oil is removed by the micro glass fiber filter that does not permeate the oil to reduce the oil in the working gas as much as possible. ing. Therefore, even if activated carbon having a finite lifetime is used as a filter means because the oil component is captured in the cells, the load of activated carbon is small and the replacement interval of activated carbon can be increased. If the primary filter case is also used as a snubber for the final stage of the compressor (not shown), the number of high-pressure vessels can be reduced, which is economical.

  In this embodiment, a micro glass fiber coreless element bonded with a fluorocarbon resin is used for the primary filter and the secondary filter of the compressor discharge line, and the primary and secondary filter elements are separated from each other. Since the inner and outer elements are arranged in a double structure, the oil collected by the inner element does not flow to the outer element as it is, and the inflow to the outer element is made uniform and the oil is removed efficiently. Is done.

  Moreover, since activated carbon is used for the tertiary filter, the oil mixed in the handled gas (compressed hydrogen gas) can be sufficiently removed to a very small amount allowed for the process, for example, 1 ppm or less. The filter performance has been improved even at high pressures where the discharge pressure is 40 MPa or more, and even for hydrogen plant compression that dislikes oil, so it is possible to inject a small amount of seal oil into the rod packing part, resulting in high efficiency. This makes it possible to realize a plunger type or piston type compressor with a long component life.

  In the above embodiment, the third-order filter structure is changed to the first-order and second-order filter structure, but the third-order filter may have the same structure as the first-order and second-order filter. In this case, parts can be shared. Note that the tertiary filter may be omitted according to demand from the demand source.

  By the way, when a gap is generated between the element and the lid cover surface or between the element and the seat plate, the gas containing oil bypasses. As a result, the oil removal performance is impaired. In order to avoid this problem, the element is pressed with a spring in the above embodiment. The rigidity of each element in the axial direction is low, and the element may be deformed or buckled if it is tightened with a tightening bolt. However, when multiple elements are formed as in the above embodiment, the deformation of the elements is prevented and the elements are securely held. Further, it is possible to prevent oil from leaking from each other by leaking the element. Further, even if a slight gap is generated between the element and the lid cover, or between the element and the seat plate, the gap is small, so that leakage can be prevented by the labyrinth effect.

  Since the elements have a multiple structure, a radial gap is formed between the elements. Since this gap is formed, the gas velocity passing through the element is made uniform. In addition, the gas passage speed in the element decreases, and the time for the gas to pass through the element becomes longer. Thereby, oil content removal performance improves. FIG. 4 shows the flow analysis results when the element is single and double. In the double element, the drift of the gas flow passing through the element is reduced.

The block diagram of one Example of the plunger-type hydrogen compressor equipment which concerns on this invention. The longitudinal cross-sectional view of the primary filter used for the hydrogen compressor installation shown in FIG. The longitudinal cross-sectional view of the tertiary filter used for the hydrogen compressor installation shown in FIG. The figure explaining the flow in an element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Gas supply port, 2 ... Compressor suction line, 3 ... 1 stage compressor, 4 ... 2 stage compressor, 5 ... 1 stage discharge line, 6 ... Intercooler, 7 ... 2 stage suction line, 8 ... 2 stage Discharge line, 9 ... after cooler, 10 ... gas filter equipment, 11 ... delivery port, 21 ... bottle case, 22 ... flange lid, 23 ... gas inlet, 24 ... gas outlet, 25 ... inner filter element, 26 ... outer filter element 27 ... Receiving seat, 28 ... Bolt, 29 ... Bolt, 30 ... Drain hole, 31 ... Bottle case, 32 ... Flange lid, 33 ... Gas inlet, 34 ... Gas outlet, 35 ... Activated carbon filter element, 36 ... Receiving seat, 37 ... bolts, 38 ... bolts.

Claims (8)

  In a multistage reciprocating compressor having a discharge pressure exceeding 40 MPa, a filter means for removing oil in the discharge gas discharged from the final compression stage is provided downstream of the final compression stage. A lid flange that covers the bottle case, and an inlet portion and an outlet portion of the discharge gas are formed in the lid flange, and the filter case made of micro glass fiber is formed in the bottle case and accommodated. A reciprocating compressor characterized by that.   The reciprocating compressor according to claim 1, wherein the multiple element includes an inner element and an outer element, and a gap is formed between the inner element and the outer element.   The reciprocating compressor according to claim 1, wherein a flow path through which discharge gas moves from an inner peripheral side to an outer peripheral side of the multiple element is formed in the filter unit.   A second filter means is connected to the downstream side of the filter means, and the second filter means is a bottle case, a lid flange for covering the bottle case, and a filter element made of micro glass fiber accommodated in the bottle case. The reciprocating compressor according to claim 1, comprising:   Third filter means is connected further downstream of the second filter means, and the third filter means comprises a bottle case, a lid flange for covering the bottle case, and an activated carbon filter accommodated in the bottle case. The reciprocating compressor according to claim 4, further comprising an element.   In a multistage reciprocating compressor having a discharge pressure exceeding 40 MPa, a filter means for removing oil in the discharge gas discharged from the final compression stage is provided downstream of the final compression stage. A lid flange that covers the bottle case and is formed with an inlet portion and an outlet portion of the discharge gas, a cylindrical filter element that is accommodated in the bottle case and formed in multiple layers, and the cylindrical filter element A seat plate that holds one end in the axial direction, a tightening bolt that is inserted through the center of the filter element and sandwiches the filter element together with the seat plate and the lid flange, and an outer periphery of the tightening bolt, A reciprocating compressor having a spring disposed between a tightening portion and the seat plate.   The reciprocating compressor according to claim 6, wherein a discharge gas passage is formed between the innermost side of the filter element and the fastening bolt. The reciprocating compressor according to any one of claims 1 to 7, wherein the discharge gas is hydrogen gas.

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