Piston compressor

Abstract

A piston compressor (10) has a crankcase (11) defining an inlet chamber (34), at least one suction chamber (36) and a crank chamber (40) forming an oil pan (42). The crankcase (11) has an inlet opening (22) leading to the inlet chamber (34). A filter (64) is mounted in the inlet chamber (34). A filter wall (66) of the filter (64) has a filter opening (68) through which, in use, sucked intake gas passes and then flows to the at least one suction chamber (36, 38). The filter (64) has a diameter and the filter opening (68) has a size such that when the piston compressor is operated at a maximum capacity, gas entering the inlet chamber (34) from inside the filter (64) through the filter wall (66) via the filter opening (68) has a flow rate lower than an entrainment speed, the filter wall (66) has a filter opening (68) such that droplets remain on the filter wall (66) and are substantially not dragged with airflow through the filter opening (68).

Description

Technical Field

[0001] The present disclosure relates to a piston compressor. Background Art

[0002] The applicant manufactures and sells a piston compressor according to the preamble of claim 1. The known piston compressor comprises a crankcase defining an inlet chamber, at least one suction chamber and a crank chamber forming an oil sump. The crankcase has an inlet opening leading to the inlet chamber. The piston compressor further comprises a crankshaft mounted in the crank chamber and at least one cylinder / piston assembly, each cylinder / piston assembly comprising a cylinder mounted in the crankcase and a piston reciprocatingly movably mounted in the cylinder and drivably connected to the crankshaft. The known piston compressor further comprises at least one cylinder head mounted on a relevant suction chamber in at least one suction chamber. At least one cylinder / piston assembly comprises a suction port having an associated suction valve. Each suction port fluidically connects the interior of at least one cylinder with the relevant suction chamber in at least one suction chamber. At least one cylinder / piston assembly further comprises a discharge port having an associated discharge valve. Each discharge port fluidically connects the interior of the corresponding cylinder with the relevant cylinder head chamber in at least one cylinder head chamber. A gas inlet pipe is connected to the crankcase so that an inlet pipe flow channel defined by the gas inlet pipe is fluidically connected to the inlet chamber via the inlet opening in the crankcase. The piston compressor comprises a filter mounted in the inlet chamber. The filter comprises a filter wall having a cylindrical shape defining a central axis of the filter. One end of the cylindrical filter wall is open and defines a filter inlet end. An inlet opening of the crankcase leads to the filter inlet end. The filter wall has a filter opening, and in use, the inhaled intake gas passes through the filter opening and then flows to at least one suction chamber. Summary of the invention

[0003] Piston compressors are used in a variety of applications, such as in chillers for compressing cooling fluids, and in other gas compression systems, such as air compression systems.

[0004] Known piston compressors are capable of compressing a gas in which a certain amount of liquid may be present. The liquid may be a condensate formed upstream of the inlet opening of the piston compressor. The liquid may also be another liquid that may be contained in the gas. However, the amount of liquid that may be present in the gas should not be so great that it enters the suction port of the piston / cylinder assembly. It is known that liquid can be removed from the compressed gas, i.e. after compression. This is done, for example, in a gas / liquid separator that conducts the compressed gas.

[0005] The object of the present disclosure is to provide a piston compressor in which the amount of liquid that may be present per volume of intake gas (e.g., in l / m 3 or kg / m 3denoted) is higher than in known piston compressors.

[0006] To this end, the piston compressor according to the preamble of claim 1 as described in the background technology section above is characterized in that, in order to collect liquid entrained in the gas upstream of the suction port, the filter has a diameter and the filter opening has a size so that when the piston compressor is operated at maximum capacity, the gas entering the inlet chamber from the inside of the filter through the filter wall via the filter opening has a flow rate lower than the entrainment rate, so that the droplets are retained on the filter wall and are substantially not dragged along with the gas flow through the filter opening.

[0007] Due to the novel and specific filter diameter and the size of the filter opening, the flow rate of the gas through the filter opening is in any case kept so low that any liquid captured by the filter and deposited on the filter wall is not entrained in the gas flowing through the filter opening. Instead, the liquid captured by the filter flows downwards through the filter wall to the bottom of the filter under the effect of gravity. At the bottom of the filter, the liquid is collected and forms larger droplets that fall under the effect of gravity. Thus, gas / liquid separation is performed upstream of the suction port of the piston / cylinder assembly by means of a specially designed and sized filter.

[0008] In one embodiment, the diameter of the filter wall and the size of the filter openings are such that the gas flow velocity through the filter openings is less than 1.7 m / s, preferably less than 1.5 m / s.

[0009] When the air flow velocity is maintained below the above values, the possibility of entrainment of droplets in the air flow through the filter opening is minimized, thereby ensuring that the liquid captured by the filter flows through the filter wall to the bottom of the filter under the action of gravity and forms larger droplets, which will fall from the filter under the action of gravity instead of being dragged with the air flow to the suction port of at least one cylinder / piston assembly.

[0010] Further embodiments are described in the remaining dependent claims and will be further elucidated in the detailed description with reference to the examples shown in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 shows a cross-sectional view of a piston compressor along a plane perpendicular to the axis of rotation of a crankshaft of the piston compressor;

[0012] Figure 2 Shows Figure 1 A similar cross-sectional view of a crankcase with a filter of a piston compressor shown in ;

[0013] Figure 3 Shows Figure 2 a cross-section along line III-III;

[0014] Figure 4 Shows Figure 2 A perspective view of the section shown in ;

[0015] Figure 5 Shows Figure 2 Details of V; and

[0016] Figure 6 Shows Figure 1 Details in VI, especially the suction port of the cylinder / piston assembly. DETAILED DESCRIPTION

[0017] In the following detailed description, reference will be made to the above-mentioned drawings. However, the various embodiments described herein are not limited to the examples shown in the drawings. In fact, the reference numerals used in the detailed description are only for illustration and do not limit the embodiments to the examples shown in the drawings.

[0018] In summary, the present invention relates to a piston compressor 10. The piston compressor 10 includes a crankcase 11 defining an inlet chamber 34, at least one suction chamber 36, and a crank chamber 40 forming an oil sump 42. The crankcase 11 has an inlet opening 22 leading to the inlet chamber 34. The piston compressor also includes a crankshaft 46 mounted in the crank chamber 40 and at least one cylinder / piston assembly 44, 48. Each cylinder / piston assembly 44, 48 includes a cylinder 44 mounted in the crankcase 11 and a piston 48 reciprocatingly movably mounted in the cylinder 44 and drivably connected to the crankshaft 46. The piston compressor 10 also includes at least one cylinder head 50 mounted on a corresponding suction chamber of at least one suction chamber 36. At least one cylinder / piston assembly 44, 48 includes a suction port 54 with an associated suction valve 56. Each suction port 54 fluidly connects the interior of at least one cylinder 44 with the corresponding suction chamber of at least one suction chamber 36, 38. At least one cylinder / piston assembly 44, 48 also includes a discharge port 58 with an associated discharge valve 60. Each discharge port 58 fluidly connects the interior of the corresponding cylinder 44 with the associated cylinder head chamber in at least one cylinder head chamber 50a, 52a. The piston compressor also includes a gas inlet pipe 62, which is connected to the crankcase 11 so that the inlet pipe flow channel 62c defined by the gas inlet pipe 62 is fluidly connected to the inlet chamber 34 via the inlet opening 22 in the crankcase 11. The filter 64 is installed in the inlet chamber 34. The filter 64 includes a filter wall 66, which has a cylindrical shape and defines the filter center axis. One end of the cylindrical filter wall 66 is open and defines a filter inlet end 69. The inlet opening 22 of the crankcase 11 leads to the filter inlet end 69. The filter wall 66 has a filter opening 68, and in use, the intake gas sucked passes through the filter opening and then flows to at least one suction chamber 36, 38.

[0019] The piston compressor 10 is characterized in that, in order to collect liquid entrained in the gas upstream of the suction port 54, the filter 64 has a certain diameter and the filter opening 68 has a certain size, so that when the piston compressor 10 is operated at maximum capacity, the gas entering the inlet chamber 34 from the inside of the filter 64 through the filter opening 68 through the filter wall 66 has a flow rate lower than the entrainment speed, so that the droplets are retained on the filter wall 66 and are not substantially dragged along with the gas flow through the filter opening 68.

[0020] The advantages of the piston compressor of the present invention are described in the invention summary section of this application (page 3, paragraph 2). For the sake of brevity, they will not be repeated here, but by citing the invention summary section, these advantages can be considered to be included here.

[0021] In one embodiment, an example of which is shown in the figure, in order to collect liquid entrained in the gas upstream of the suction port 54, the piston compressor 10 may include a cone 70 having a central cone axis coinciding with the central axis of the filter. The first end of the cone 70 with the smallest diameter is located at the filter inlet end. The second end of the cone 70 with the largest diameter is located at the other end of the filter 64 opposite to the filter inlet end.

[0022] The cone 70 can be a true cone including a mathematical cone tip. However, the cone 70 can also have a round tip. In another embodiment, the cone 70 can be a truncated cone. In the example shown in the figure, the cone 70 is similar to a cone 70 whose tip portion is round near the filter inlet end. Since the cone 70 is present in the cylindrical filter 64, the flow rate of the gas through the filter opening 68 is basically constant at the inlet end of the filter 64 and the end of the filter opposite to the filter inlet end 69. In other words, the flow direction of the gas entering the filter 64 via the inlet opening 22 is basically along the axial direction of the filter 64. However, the gas leaves the filter 64 via the filter opening. When observed along the axial direction of the filter from the filter inlet end 69 to the other end of the filter, the cone 70 provides a decreasing flow cross section. Therefore, even if the gas leaves the filter 64 via the filter opening 68, the static and dynamic pressures at various positions along the length of the filter 64 in the filter remain basically constant. As a result, an improved substantially constant gas outflow velocity through the filter opening 68 over the length of the filter 64 is obtained, and the gas supply to the suction chambers 36 , 38 can be substantially constant over the entire length of the piston compressor 10 .

[0023] In one embodiment, an example of which is shown in the figure, the piston compressor 10 can be configured so that, in order to collect liquid entrained in the gas upstream of the suction port 54, the minimum flow distance between the filter 64 and any one of the suction ports 54 is such that any droplets released from the filter 64 and dragged with the gas flow fall before reaching the suction port 54.

[0024] In rare cases, liquid droplets may be released from the filter 64 and entrained in the airflow, such as when a shock wave in the airflow occurs due to some switching in the downstream compressed gas channel system or the upstream suction channel system, and this embodiment further reduces the chance of liquid reaching the suction port 54. Therefore, the possibility of corresponding damage can be reduced.

[0025] In one embodiment, an example of which is shown in the figure, the gas inlet pipe 62 may have an inlet end 62a with a flange 88 and an outlet end 62b connected to the crankcase 11. The gas inlet pipe 62 may be in the shape of an elbow, and its inlet pipe flow channel 62c defines a central axis L3 of the inlet pipe flow channel that is bent 90 degrees. In order to collect liquid entrained in the gas upstream of the suction port 54, the flange 88 may be offset relative to the central axis L3 of the inlet pipe flow channel toward the outer curved portion 62d of the gas inlet pipe 62, thereby promoting the collection of liquid on the outer curved portion 62d of the gas inlet pipe 62.

[0026] Since the gas inlet pipe 62 has such a structure, any liquid entrained in the suction flow of the gas inlet pipe 62 will be forced to flow to the wall of the inlet pipe under the action of centrifugal force, especially to the wall defining the outer curved portion 62d. Since the flange 88 is offset toward the outer curved portion 62d relative to the central axis L3 of the inlet pipe flow channel, the possibility of the droplets actually reaching the inlet pipe wall is increased. This will result in more small droplets being collected on the inlet pipe wall, and a liquid stream will be formed in the gas inlet pipe 62. The liquid stream will enter the filter 64 at its bottom, and then leave the filter in the form of large and heavy droplets or even liquid streams due to gravity. These large and heavy droplets or liquid streams will not be entrained by the airflow leaving the filter opening 68, and therefore will not reach the suction port 54 of the cylinder / piston assembly.

[0027] In one embodiment, an example of which is shown in the figure, in order to collect the liquid entrained in the gas upstream of the suction port 54, the elbow-shaped gas inlet pipe 62 can define an inlet pipe flow channel 62c, which has a gradually expanding cross-sectional area from the inlet end 62a toward the outlet end 62b, thereby reducing the flow rate of the gas therein. The gradually expanding cross-sectional area can be applied independently of the above-mentioned offset flange embodiment, and can also be applied in combination with it. The gradually expanding cross-sectional area of ​​the inlet pipe flow channel 62c does cause the flow rate of the gas therein to decrease when flowing from the inlet end 62a toward the outlet end 62b. Due to the reduction in gas flow rate, the chance of droplets entrained in the gas flow falling and collecting on the bottom of the tube wall of the gas inlet pipe 62 is greater than when the gas flow rate is not reduced. Therefore, this feature also improves the collection of liquid before the liquid reaches the suction port 54 of at least one cylinder / piston assembly.

[0028] In one embodiment, the piston compressor 10 may include an electronic controller 90 and a temperature sensor 92 for measuring the temperature of the oil in the oil sump 42. The electronic controller 90 is configured to shut down the piston compressor 10 when the oil temperature drops below 30°C.

[0029] The liquid collected before reaching the suction port 54 will first be stored in various liquid buffer reservoirs 72, 74, 76 within the crankcase 11, embodiments of which will be described below. In these liquid buffer reservoirs 72, 74, 76, the liquid may evaporate. However, if the supply of liquid exceeds the evaporation rate, the liquid buffer reservoirs 72, 74, 76 may eventually overflow and the liquid will eventually enter the oil pan 42. Therefore, the oil temperature in the oil pan can indicate the amount of liquid discharged from one or more liquid buffer reservoirs 72, 74, 76 into the oil pan 42. When the oil temperature drops below the required temperature, according to the present embodiment, this may indicate that there may be a problem with the amount of liquid in the supply gas flow and the piston compressor 10 should be shut down to prevent damage to the piston compressor 10 or other problems.

[0030] In one embodiment, an example of which is shown in the figure, in order to collect liquid entrained in the gas upstream of the suction port 54, the lower portion of the inlet chamber 34 can form an inlet chamber liquid buffer reservoir 72.

[0031] In one embodiment, an example of which is shown in the figure, in order to collect liquid entrained in the gas upstream of the suction port 54, the lower portion of at least one suction chamber 36, 38 can form a suction chamber liquid buffer reservoir 74, 76.

[0032] In further elaboration of the embodiment having the suction chamber liquid buffer reservoir 74, 76, the wall separating the at least one suction chamber 36, 38 from the crank chamber 40 and defining the suction chamber liquid buffer reservoir 74, 76 may include a pressure balance opening 80 that connects the at least one suction chamber 36, 38 with the crank chamber 40. The pressure balance opening 80 may be located at a height above the bottom of the at least one suction chamber 36, 38 such that each suction chamber liquid buffer reservoir 74, 76 has a capacity of at least 0.5 liters per cylinder 44, preferably greater than 1 liter per cylinder 44, and more preferably at least 1.5 liters per cylinder 44.

[0033] In an alternative further elaboration of the embodiment with the suction chamber liquid buffer reservoir 74, 76, the wall separating the at least one suction chamber 36, 38 from the crank chamber 40 and defining the suction chamber liquid buffer reservoir 74, 76 may include a pressure balance opening 80, which connects the at least one suction chamber 36, 38 with the crank chamber 40, as was the case in the previous further elaboration of the embodiment. However, in this alternative, in each pressure balance opening, the bushing 82 is provided with a bushing inlet opening 84 in the corresponding suction chamber and a bushing outlet opening 86 in the crank chamber 40. The bushing inlet opening 84 in each bushing 82 is located at a height above the bottom of the corresponding at least one suction chamber 36, 38, so that each suction chamber liquid buffer reservoir 74, 76 has a capacity of at least 0.5 liters per cylinder 44, preferably more than 1 liter per cylinder 44, and more preferably at least 1.5 liters per cylinder 44.

[0034] In any of the further elaborations above, the amount of liquid that can be buffered in the suction chamber liquid buffer reservoir 74, 76 is relatively high, which means that more time is required for the suction chamber liquid buffer reservoir to overflow and discharge the liquid into the oil sump 42. The more liquid that can be stored in the suction chamber liquid buffer reservoir 74, 76, the longer the time available for evaporation, and thus the greater the chance that the liquid evaporates before the suction chamber liquid buffer reservoir 74, 76 overflows. Therefore, due to the large liquid buffer capacity, the piston compressor 10 can be prevented from accidentally shutting down.

[0035] In one embodiment, an example of which is shown in the figure, the piston compressor can have a V-shaped configuration. In this configuration, the crankcase 11 may include a body 12, which is defined by a body wall 14 extending along the longitudinal main axis L1 of the body 12. The body 12 includes a first cylinder receiving groove 16. The crankcase 11 also includes a first end wall 18 and a second end wall 20, which close the two opposite ends of the body 12. The first end wall 18 includes an inlet opening 22. In addition, the crankcase 11 includes a cylinder support 24, which has an inverted V shape along a cross-section of a plane perpendicular to the longitudinal main axis L1. The cylinder support 24 has two longitudinal edges 24a, 24b extending parallel to the longitudinal main axis L1 line. The two longitudinal edges 24a, 24b are connected to the body wall 14. In addition, the cylinder support 24 has two opposite end edges 24c, which are respectively connected to the two opposite first and second end walls 18, 20. The cylinder support 24 includes a second cylinder receiving groove 26. The crankcase 14 also includes a first reinforcement wall 28 and a second reinforcement wall 30, each of which extends parallel to the longitudinal main axis L1, and each reinforcement wall has a first longitudinal edge 28a, 30a, a second longitudinal edge 28b, 30b and two opposite end edges. The first longitudinal edge 28a, 30a of each reinforcement wall 28, 30 is connected to the cylinder support 24, and the second longitudinal edge 28b, 30b is connected to the main body wall 14. The opposite end edges are connected to the first end wall and the second end wall 18, 20. The first reinforcement wall 28 and the second reinforcement wall 30 both include a gas passage opening 32. In this configuration, the inlet chamber 34 is defined by the upper part of the main body wall 14, the two reinforcement walls and the upper part of the cylinder support 24. The inlet chamber 34 extends from the first end wall 18 to the second end wall 20 parallel to the longitudinal main axis L1. At least one suction chamber 36, 38 includes a first suction chamber 36 and a second suction chamber 38. The first suction chamber 36 is defined by the first portion of the cylinder support 24, the first reinforcement wall 28, and the first suction chamber defining a portion of the main body wall 14. The first suction chamber 36 extends from the first end wall 18 to the second end wall 20 in parallel with the longitudinal main axis L1. The second suction chamber 38 is defined by the second portion of the cylinder support 24, the second reinforcement wall 30, and the second suction chamber defining a portion of the main body wall 14. The second suction chamber 38 extends from the first end wall 18 to the second end wall 20 in parallel with the longitudinal main axis L1. In this embodiment, the crankshaft chamber 40 is defined by the cylinder support 24 and the crankshaft chamber defining a portion of the main body wall 14.

[0036] This embodiment of the crankcase 11 is strong and rigid and provides an internal air flow passage that may be relatively wide, so that the air flow velocity may be relatively low, thereby preventing or at least reducing the entrainment of liquid droplets in the air flow within the piston compressor 10. Each liquid buffer reservoir 72, 74, 76 is formed by structural components of the crankcase 11, which are arranged in the crankcase 11 to provide support for the cylinder 44 (cylinder support 24) and provide additional rigidity to the crankcase 11 (first and second reinforcing walls 28, 30). Therefore, the liquid buffer reservoirs 72, 74, 76 are formed with a minimum of additional components and therefore with a minimum of additional manufacturing cost.

[0037] In one embodiment, an example of which is shown in the figure, the main body wall 14, the first and second end walls 18, 20, and the cylinder support 24 may include bent steel plates. The first and second reinforcing walls 28, 30 may also include flat steel plates or bent steel plates. This has the advantages of relatively low manufacturing costs and very good heat conduction to the environment. The connection between the main body wall 14, the first and second end walls 18, 20, the cylinder support 24 and the first and second reinforcing walls 28, 30 may be a welded connection. The main body 12 may have a substantially constant cross-section along any cross-section extending perpendicular to the main axis L1.

[0038] In further detail of an embodiment having a V-shaped structure, the first longitudinal edges 28a, 30a of the first and second reinforcing walls 28, 30 are connected to the cylinder support 24 at the intermittent connection sections 28d, 30d. There are liquid-transmissive gaps 28e, 30e between the intermittent connection sections 28d, 30d, which separate the respective first longitudinal edges 28a, 30a from the cylinder support 24. In addition, the opposite end edges of the first and second reinforcing walls 28, 30 are connected to the first and second end walls 18, 20 in a fluid-tight manner, thereby providing an inlet chamber liquid buffer reservoir 72 in the lower part of the inlet chamber 34. The inlet chamber liquid buffer reservoir 72 extends from the first end wall 18 to the second end wall 20. Therefore, in a very efficient manner, the inlet chamber liquid buffer reservoir 72 is made of components of the crankcase 11 that are used for other purposes, namely the reinforcing walls 28, 30 and the cylinder support 24. This is beneficial in terms of material usage and cost as well as manufacturing time and cost. The liquid transmission slits 28e, 30e enable the liquid collected in the inlet chamber liquid buffer reservoir 72 to slowly flow out of the inlet chamber liquid buffer reservoir 72 and flow through the cylinder support 24. During the flow of the liquid through the cylinder support 24, part of the liquid may evaporate, which helps to block the unwanted liquid solution in the suction port 54. In addition, the evaporated liquid cools the cylinder support 24. Since the oil in the oil pan 42 and the rotating crankshaft 46 will splash onto the cylinder support 24, the cooling of the cylinder support by the evaporated liquid flowing through the cylinder support 24 will help cool the oil, which helps prevent the oil from overheating, thereby extending the service life of the oil. The liquid that is not evaporated during the flow through the cylinder support 24 is collected in the first and second suction chamber liquid buffer reservoirs 74, 76, where it has more time to stay, thereby providing the possibility of evaporation.

[0039] In one embodiment, the gas passage openings 32 in the first reinforcement wall 28 and the gas passage openings 32 in the second reinforcement wall 30 have such a size that when the piston compressor 10 is operated at maximum capacity, the gas entering the first and second suction chambers 36, 38 from the inlet chamber 34 through these gas passage openings 32 has a flow velocity lower than the entrainment velocity, so that substantially no liquid droplets are dragged along with the gas flow through the gas passage openings 32.

[0040] Again, this is to minimise the risk of liquid being drawn into the cylinder via the suction port 54. Due to the relatively low flow rate, any droplets in the air stream are more likely to fall out under gravity rather than being transported to the suction port 54 by the air stream.

[0041] In yet another embodiment, similarly, each longitudinal edge 24a, 24b of the cylinder support 24 can be connected to the main body wall 14 in a fluid-tight manner along its entire length. Similarly, the two opposite end edges 24c of the cylinder support 24 are connected to the two opposite end walls 18, 20 in a fluid-tight manner, respectively, so as to provide a first suction chamber liquid buffer reservoir 74 at the lower part of the first suction chamber 36 and a second suction chamber liquid buffer reservoir 76 at the lower part of the second suction chamber 38. The first and second suction chamber liquid buffer reservoirs 74, 76 each extend from the first end wall 18 to the second end wall 20. Therefore, in a very efficient manner, the suction chamber liquid buffer reservoirs 74, 76 are made of components of the crankcase 11 that are used for other purposes (i.e., the main body wall 14 and the cylinder support 24). This is beneficial to material usage and cost as well as manufacturing time and cost.

[0042] Although the illustrative embodiments of the present invention have been described above in part with reference to the accompanying drawings, it should be understood that the present invention is not limited to these embodiments. Those skilled in the art can understand and implement variations to the disclosed embodiments in practicing the claimed invention by studying the drawings, the disclosure, and the appended claims.

[0043] References to "one embodiment" or "an embodiment" in this specification mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places in this specification do not necessarily refer to the same embodiment.

[0044] Furthermore, it should be noted that the specific features, structures, or characteristics of one or more embodiments described above may be used and implemented independently of each other, and may be combined in any suitable manner to form new, not explicitly described embodiments. The reference numerals used in the detailed description and claims do not limit the description of the embodiments, nor the claims. The reference numerals are used for clarity only.

[0045] Components List

[0046] 10. Piston compressor

[0047] 11. Crankcase

[0048] 12. Subject

[0049] 14. Main wall

[0050] 16.First cylinder receiving groove

[0051] 18. First end wall

[0052] 20. Second end wall

[0053] 22. Inlet opening in first end wall

[0054] 24. Cylinder support

[0055] 24a. The first longitudinal edge of the cylinder support

[0056] 24b. The second longitudinal edge of the cylinder support

[0057] 24c. Opposite end edges of the cylinder support

[0058] 26. Second cylinder receiving groove

[0059] 28. The first reinforcement wall

[0060] 28a. The first longitudinal edge of the first reinforcing wall

[0061] 28b. The second longitudinal edge of the first reinforcing wall

[0062] 30. Second reinforcement wall

[0063] 30a. The first longitudinal edge of the second reinforcing wall

[0064] 30b. The second longitudinal edge of the second reinforcing wall

[0065] 32. Gas channel opening

[0066] 34. Entrance Room

[0067] 36. First suction chamber

[0068] 38. Second suction chamber

[0069] 40. Crankshaft chamber

[0070] 42. Oil pan

[0071] 44. Cylinder

[0072] 46. ​​Crankshaft

[0073] 48. Piston

[0074] 50.First cylinder head

[0075] 50a. First cylinder head chamber

[0076] 52. Second cylinder head

[0077] 52a. Second cylinder head chamber

[0078] 54.Suction port

[0079] 56.Suction valve

[0080] 58. Exhaust

[0081] 60.Discharge valve

[0082] 62. Gas inlet pipe

[0083] 62a. Inlet end of gas inlet pipe

[0084] 62b. Outlet end of gas inlet pipe

[0085] 62c. Inlet pipe flow channel

[0086] 62d. Outer bend of gas inlet pipe

[0087] 64. Filter

[0088] 66.Filter wall

[0089] 68.Filter opening

[0090] 69.Filter inlet

[0091] 70. Cone

[0092] 72. Inlet chamber liquid buffer storage

[0093] 74. First suction chamber liquid buffer storage

[0094] 76. Second suction chamber liquid buffer storage

[0095] 78.First pressure balance opening

[0096] 80. Second pressure balance opening

[0097] 82.Bushing

[0098] 84.Bushing inlet opening

[0099] 86.Bushing outlet opening

[0100] 88. Flange of gas inlet pipe

[0101] 90. Electronic controller

[0102] 92. Temperature sensor

[0103] L1. Longitudinal main axis

[0104] L3. Center axis of inlet pipe flow channel

Claims

1. A piston compressor (10), comprising: a crankcase (11) defining an inlet chamber (34), at least one suction chamber (36) and a crankcase (40) forming an oil sump (42), the crankcase (11) having an inlet opening (22) leading to the inlet chamber (34); a crankshaft (46) mounted in the crankshaft chamber (40); at least one cylinder / piston assembly (44, 48), each cylinder / piston assembly comprising a cylinder (44) mounted in the crankcase (11) and a piston (48) reciprocatingly movably mounted in the cylinder (44) and drivably connected to the crankshaft (46); at least one cylinder head (50, 52) mounted to an associated one of the at least one suction chambers (36, 38); The at least one cylinder / piston assembly (44, 48) includes a suction port (54) having an associated suction valve (56), wherein each suction port (54) fluidly connects the interior of the at least one cylinder (44) with an associated suction chamber of the at least one suction chamber (36, 38); The at least one cylinder / piston assembly (44, 48) includes a discharge port (58) having an associated discharge valve (60), wherein each discharge port (58) fluidly connects the interior of a corresponding cylinder (44) with an associated cylinder head chamber of the at least one cylinder head chamber (50a, 52a); a gas inlet pipe (62) connected to the crankcase (11) so as to fluidly connect an inlet pipe flow passage (62c) defined by the gas inlet pipe (62) to the inlet chamber (34) via an inlet opening (22) in the crankcase (11); a filter (64) mounted in the inlet chamber (34), the filter (64) comprising a filter wall (66) having a cylindrical shape defining a filter central axis, one end of the cylindrical filter wall (66) being open and defining a filter inlet end (69), the inlet opening (22) of the crankcase (11) leading to the filter inlet end (69), the filter wall (66) having a filter opening (68), wherein in use, the sucked intake gas passes through the filter opening and subsequently flows to the at least one suction chamber (36, 38); It is characterized in that In order to collect liquid entrained in the gas upstream of the suction port (54), the filter (64) has a diameter and the filter opening (68) has a size so that when the piston compressor (10) is operating at maximum capacity, the gas entering the inlet chamber (34) from the interior of the filter (64) through the filter opening (68) through the filter wall (66) has a flow rate lower than the entrainment rate, so that liquid droplets are retained on the filter wall (66) and are not substantially entrained with the gas flow through the filter opening (68).

2. The piston compressor (10) according to claim 1, wherein: The diameter of the filter wall and the size of the filter opening are such that the gas flow velocity through the filter opening is less than 1.7 m / s, preferably less than 1.5 m / s.

3. The piston compressor (10) according to claim 1 or 2, wherein: In order to collect liquid entrained in the gas upstream of the suction port (54), the piston compressor (10) includes a cone (70) having a central cone axis coinciding with the central axis of the filter, wherein the first end of the cone (70) with the smallest diameter is located at the inlet end of the filter, and wherein the second end of the cone (70) with the largest diameter is located at the other end of the filter (64) opposite to the inlet end of the filter.

4. The piston compressor (10) according to any one of the preceding claims, wherein: In order to collect liquid entrained in the gas upstream of the suction port (54), the minimum flow distance between the filter (64) and any one suction port (54) allows any droplets of liquid released from the filter (64) and dragged with the gas flow to fall before reaching the suction port (54).

5. The piston compressor (10) according to any one of the preceding claims, wherein: The gas inlet pipe (62) has an inlet end (62a) with a flange (88) and an outlet end (62b) connected to the crankcase (11), wherein the gas inlet pipe (62) is in the shape of an elbow, and its inlet pipe flow channel (62c) defines an inlet pipe flow channel center axis (L3) bent 90 degrees, wherein in order to collect liquid entrained in the gas upstream of the suction port (54), the flange (88) is offset relative to the inlet pipe flow channel center axis (L3) toward the outer curved portion (62d) of the gas inlet pipe (62) so as to promote the collection of liquid on the outer curved portion (62d) of the gas inlet pipe (62).

6. The piston compressor (10) according to any one of the preceding claims, wherein: The gas inlet pipe (62) has an inlet end (62a) with a flange (88) and an outlet end (62b) connected to the crankcase (11), wherein the gas inlet pipe (62) is in the shape of an elbow, and its inlet pipe flow channel (62c) defines an inlet pipe flow channel central axis (L3) bent 90 degrees, wherein in order to collect liquid entrained in the gas upstream of the suction port (54), the inlet pipe flow channel (62c) has a cross-sectional area that gradually expands from the inlet end (62a) toward the outlet end (62b) to reduce the flow rate of the gas therein.

7. A piston compressor (10) according to any one of the preceding claims, comprising an electronic controller (90) and a temperature sensor (92) for measuring the temperature of the oil in the oil sump (42), wherein: The electronic controller (90) is configured to shut down the piston compressor (10) when the oil temperature drops below 30°C.

8. The piston compressor (10) according to any one of the preceding claims, wherein: In order to collect liquid entrained in the gas upstream of the suction port (54), the lower portion of the inlet chamber (34) forms an inlet chamber liquid buffer reservoir (72).

9. The piston compressor (10) according to any one of the preceding claims, wherein: In order to collect liquid entrained in the gas upstream of the suction port (54), a lower portion of the at least one suction chamber (36, 38) forms a suction chamber liquid buffer reservoir (74, 76).

10. The piston compressor (10) according to claim 9, wherein: A wall separating at least one suction chamber (36, 38) from the crank chamber (40) and defining the suction chamber liquid buffer reservoir (74, 76) includes a pressure balance opening (80) connecting at least one suction chamber (36, 38) to the crank chamber (40), the pressure balance opening (80) being located at a height above the bottom of at least one suction chamber (36, 38) so that each suction chamber liquid buffer reservoir (74, 76) has a capacity of at least 0.5 liters per cylinder (44), preferably greater than 1 liter per cylinder (44), and more preferably at least 1.5 liters per cylinder (44).

11. The piston compressor (10) according to claim 9, wherein: A wall separating at least one suction chamber (36, 38) from the crank chamber (40) and defining the suction chamber liquid buffer reservoir (74, 76) includes a pressure balance opening (80) connecting at least one suction chamber (36, 38) to the crank chamber (40), wherein in each pressure balance opening, a bushing (82) is provided with a bushing inlet opening (84) in the corresponding suction chamber and a bushing outlet opening (86) in the crank chamber (40), wherein the bushing inlet opening (84) in each bushing (82) is located at a height above the bottom of the corresponding at least one suction chamber (36, 38), so that each suction chamber liquid buffer reservoir (74, 76) has a capacity of at least 0.5 liters per cylinder (44), preferably greater than 1 liter per cylinder (44), and more preferably at least 1.5 liters per cylinder (44).

12. A piston compressor according to any one of the preceding claims, wherein: The piston compressor has a V-shaped configuration, wherein the crankcase (11) comprises: A body (12) defined by a body wall (14) extending along a longitudinal main axis (L1) of the body (12), the body (12) including a first cylinder receiving recess (16); a first end wall (18) and a second end wall (20) closing two opposite ends of the body (12), the first end wall (18) including the inlet opening (22); a cylinder support member (24) having an inverted V-shape in cross section along a plane perpendicular to the longitudinal main axis (L1), wherein the cylinder support member (24) has two longitudinal edges (24a, 24b) extending parallel to the longitudinal main axis (L1) and connected to the main body wall (14), wherein the cylinder support member (24) has two opposite end edges (24c) connected to two opposite first end walls and second end walls (18, 20), respectively, and the cylinder support member (24) includes a second cylinder receiving groove (26); a first reinforcing wall (28) and a second reinforcing wall (30), each extending parallel to the longitudinal main axis (L1) and each having a first longitudinal edge (28a, 30a), a second longitudinal edge (28b, 30b) and two opposite end edges, wherein the first longitudinal edge (28a, 30a) of each reinforcing wall (28, 30) is connected to the cylinder support (24), and the second longitudinal edge (28b, 30b) is connected to the main body wall (14), wherein the opposite end edges are connected to the first end wall and the second end wall (18, 20), and the first reinforcing wall (28) and the second reinforcing wall (30) each include a gas passage opening (32); The inlet chamber (34) is defined by the upper portion of the main body wall (14), the two reinforcing walls and the upper portion of the cylinder support (24), and the inlet chamber (34) extends parallel to the longitudinal main axis (L1) from the first end wall (18) to the second end wall (20); The at least one suction chamber (36, 38) includes a first suction chamber (36) defined by a first portion of the cylinder support (24), the first reinforcement wall (28) and a first suction chamber defining a portion of the body wall (14), the first suction chamber (36) extending parallel to the longitudinal main axis (L1) from the first end wall (18) to the second end wall (20); The at least one suction chamber (36, 38) includes a second suction chamber (38) defined by a second portion of the cylinder support (24), the second reinforcement wall (30) and a second suction chamber defining a portion of the body wall (14), the second suction chamber (38) extending parallel to the longitudinal main axis (L1) from the first end wall (18) to the second end wall (20); The crank chamber (40) is defined by the cylinder support (24) and a crank chamber defining a portion of the body wall (14).

13. The piston compressor according to claim 12, wherein: The main body wall (14), the first end wall and the second end wall (18, 20), and the cylinder support (24) comprise bent steel plates, and the first reinforcement wall and the second reinforcement wall (28, 30) comprise flat steel plates or bent steel plates, the main body wall (14), the first end wall and the second end wall (18, 20), the cylinder support (24), and the first reinforcement wall and the second reinforcement wall (28, 30) are connected by welding, and the main body (12) has a substantially constant cross-section along any cross-section extending perpendicular to the main axis (L1).

14. The piston compressor (10) according to any one of claims 12 and 13, wherein: The first longitudinal edges (28a, 30a) of the first and second reinforcing walls (28, 30) are connected to the cylinder support (24) at intermittent connection sections (28d, 30d), wherein a liquid-transmissive gap (28e, 30e) is present between the intermittent connection sections, which separates the corresponding first longitudinal edges (28a, 30a) from the cylinder support (24), wherein the opposite end edges of the first and second reinforcing walls (28, 30) are connected to the first and second end walls (18, 20) in a fluid-tight manner, thereby providing the inlet chamber liquid buffer reservoir (72) at a lower portion of the inlet chamber (34), the inlet chamber liquid buffer reservoir (72) extending from the first end wall (18) to the second end wall (20).

15. The piston compressor (10) according to any one of claims 12 to 14, wherein: The gas passage opening (32) in the first reinforcing wall (28) and the gas passage opening (32) in the second reinforcing wall (30) are sized so that when the piston compressor (10) is operated at maximum capacity, the gas entering the first suction chamber and the second suction chamber (36, 38) from the inlet chamber (34) through these gas passage openings (32) has a flow rate lower than the entrainment speed, so that substantially no liquid droplets are dragged along with the gas flow through the gas passage openings (32).

16. A piston compressor (10) according to any one of claims 12 to 15, when dependent on claim 9, wherein each longitudinal edge (24a, 24b) of the cylinder support member (24) is connected to the main body wall (14) in a fluid-tight manner along its entire length, and the two opposite end edges (24c) of the cylinder support member (24) are respectively connected to two opposite end walls (18, 20) in a fluid-tight manner, thereby providing a first suction chamber liquid buffer reservoir (74) at the lower part of the first suction chamber (36) and a second suction chamber liquid buffer reservoir (76) at the lower part of the second suction chamber (38), the first suction chamber liquid buffer reservoir and the second suction chamber liquid buffer reservoir (74, 76) each extending from the first end wall (18) to the second end wall (20).

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