JPH10141262A - Water lubricating-type screw compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with a timing gear by improving sealing performance in a water lubricant-type screw compressor for performing lubrication, cooling and sealing in a space by injecting water into a compression action space. SOLUTION: In a male screw rotor 2, rotor tooth parts 5 made of a thermosetting synthetic resin are integrally provided on the outer periphery of a metallic center shaft 12. A female screw rotor 3 is formed of stainless steel. The female screw rotor 3 is rotated and driven by drive force transmitted to the center shaft 12 of the male screw rotor 2 from a prime mover. Since the rotor tooth parts 5 of the male screw rotor 2 are formed of the synthetic resin having good fitting ability, sealing performance of the rotor tooth parts 5 on the male side, rotor tooth parts 6 on the female side and a cylinder 4 is improved, and sealing performance is not deteriorated even if water W having low density and inferior sealing performance is used as lubricating liquid. Since the female screw rotor 3 is directly rotated and driven by the male screw rotor 2, a timing gear can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-lubricated screw compressor which jets water into a compression working space to lubricate, cool and seal the space.

[0002]

A water-lubricated screw compressor jets water into a compression working space and lubricates, cools and seals the space to compress gas such as air. Compared to a screw compressor, that is, a screw compressor that injects oil into a compression working space, it is used in medical machines and food manufacturing machines because it does not contain oil in the discharged compressed gas.

In such a water-lubricated screw compressor, since water is injected into a compression working space, rotor teeth in the space are always in contact with water, and a casing (cylinder) in contact with the water is used. ), Each part of the male and female screw rotors must be rust-proofed. For this purpose, iron screw rotors are conventionally provided with rust prevention such as plating or other surface treatment for rust prevention, or both male and female screw rotors are formed of rust-resistant metal such as stainless steel, or phenol resin or synthetic resin. It was formed from a resin material such as resin.

However, in the case of an iron screw rotor having a plating or other surface treatment, it is necessary to provide a timing gear for synchronously rotating the male and female screw rotor shafts and to maintain the meshing gap between the two at an appropriate value for driving. There is a problem that the structure becomes complicated and expensive and large. That is, when the rotor teeth of the male-female-pair screw rotor made of iron are directly meshed with each other, since the cooling medium liquid is water, the viscosity is lower than that of oil and a proper liquid film cannot be formed. There is a fear that so-called galling may occur in the rotor teeth where the gears mesh. Therefore, the engagement between the male and female screw rotors must be in a non-contact state.
However, when the meshing of the screw rotor is set in the non-contact state as described above, a certain gap is generated between the meshing teeth of the rotor tooth portion, but the viscosity of water ejected into the working space is lower than that of oil. It is low and cannot provide a sufficient sealing action, and there is a problem that leakage of the compressed gas occurs to some extent. Furthermore, when surface treatment such as plating is applied to male and female screw rotors, it is difficult to form a surface treatment layer with a uniform thickness on the rotor teeth that have complicated shapes and require high precision. There is also the problem of poor sex.

When the male and female screw rotors are made of a rust-resistant metal such as stainless steel, the rust-resistant metal such as stainless steel is inferior in workability in addition to the above surface treatment problems. Furthermore, the male and female screw rotors made of synthetic resin have higher slipperiness than metal itself, so the male screw rotor is directly driven by a driving motor without a timing gear, and the female screw rotor is rotationally driven. be able to. However, when both the male and female screw rotors are formed of a synthetic resin, there is a concern that the strength of each rotor tooth is insufficient. In particular, the tooth thickness of the rotor tooth portion of the female screw rotor is thinner than the rotor tooth portion of the male screw rotor, so that the female screw rotor is easily deformed or abnormally worn during operation. For example, when the tooth thickness is increased as a countermeasure, there remains a problem that the volume of the compression action space is reduced and performance is reduced.

Further, as in a hydraulic screw compressor disclosed in Japanese Patent Publication No. 38-24279, a male screw rotor is made of metal, and the other female screw rotor is formed of a nonmetal-abrasive material such as phenolic resin. Some screw rotors are driven directly by meshing the female screw rotor with the main driving shaft.However, when water is used as the liquid medium to be supplied to the compression working space, such as a water-lubricated screw compressor, sufficient rust prevention is required. Measures are needed. In particular, it is expensive to use the rust-resistant metal material for the male screw rotor 2 which is heavier than the female screw rotor, and the workability is poor. At the same time, when the compressor is started, it is driven to rotate with the metal screw rotor side, which has a large specific weight, as the main drive shaft, so the moment of inertia at the time of start is also large, and the instantaneous load force There is a problem that becomes large.

Accordingly, an object of the present invention is to provide a water-lubricated screw compressor that solves the above-mentioned problems and improves the performance of the device, and also reduces the size and weight of the device and reduces the cost.

[0008]

According to a first aspect of the present invention, a male and female screw rotor meshing with each other is rotatably housed in a casing, and water is spouted into a compression working space. In a water-lubricated screw compressor that performs lubrication, cooling, and sealing in the space, at least the rotor tooth portion of any one of the pair of screw rotors is formed of a thermosetting synthetic resin, A water-lubricated screw compressor characterized in that at least the rotor teeth of the other screw rotor are formed of a rust-resistant metal, wherein the rotor teeth of the pair are formed of a thermosetting synthetic resin and a metal. Therefore, even if both are directly engaged, the familiarity between the two is good, and the sealing performance of the compression action space can be enhanced.

According to a second aspect of the present invention, a rotor tooth portion of the male screw rotor is formed of a thermosetting synthetic resin,
2. The water-lubricated screw compressor according to claim 1, wherein rotor teeth of said female screw rotor are formed of stainless steel, and a male screw rotor having a large volume is made of thermosetting synthetic resin. Since the weight of the entire water-lubricated screw compressor can be reduced, and the rotor teeth of the male screw rotor having a large surface area are made of thermosetting synthetic resin, the adaptability between the end face of the rotor and the casing can be improved.

According to a third aspect of the present invention, the male screw rotor is formed by integrally forming a rotor tooth portion made of the thermosetting synthetic resin on an outer periphery of a metal center shaft. This is a water-lubricated screw compressor, in which a predetermined strength can be ensured by a metal central shaft, and the weight of the male screw rotor can be reduced.

According to a fourth aspect of the present invention, male and female screw rotors meshing with each other are rotatably housed in a casing, and water is jetted into a compression working space to lubricate and cool the space. In a water-lubricated screw compressor adapted to perform sealing, the male screw rotor is integrally formed with a rotor tooth portion made of a thermosetting synthetic resin on the outer periphery of a metal center shaft, and the female screw rotor is made of stainless steel. Wherein the driving force of a driving motor is transmitted to a central axis of the male screw rotor, and the female screw rotor is rotationally driven by the male screw rotor. Thus, the moment of inertia of the male screw rotor can be reduced, and the instantaneous load power at the time of starting the male screw rotor by the prime mover can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a casing of the screw compressor,
A cylinder portion 4 for rotatably housing male and female screw rotors 2 and 3 is formed in the steel casing 1.
The rotor teeth 5 of the male screw rotor 2 and the rotor teeth 6 of the female screw rotor 3 are designed to mesh with each other and rotate. An unloader valve 9 for controlling the amount of intake air is provided in the upper part of the casing 1 in the middle of a suction passage 8 extending from the suction port 7 to the suction side opening 4A of the cylinder section 4. The unloader valve 9 rotates and closes when the internal pressure of a receiver tank (not shown) that stores compressed air rises to a predetermined pressure by a regulator device (not shown), and opens when the pressure drops below the predetermined pressure. I have. Further, a discharge path 11 is provided between the discharge side opening 4B of the cylinder part 4 and a discharge port 10 provided at the lower part on the other side of the casing 1.
The compressed air compressed by the compression action space S surrounded by the rotor teeth 5 and 6 and the cylinder section 4 from the discharge path 11 and the water W jetted into the compression action space S from the water ejection port 4C provided in the cylinder section 4. Are discharged in a gas-liquid mixed state.

The male screw rotor 2 has a rotor tooth 5 formed by integrally molding a thermosetting resin on the outer periphery of a central shaft 12 made of steel such as metal. That is, after the center shaft 12 is housed in a molding die (not shown), a thermosetting resin such as a phenol resin, an epoxy resin, a diallyl phthalate resin, an unsaturated polyester resin, a polyimide resin, a melamine resin, and a silicone resin is filled. And molding,
A crosslinked structure is formed by heating at a high temperature.
Further, the base ends 13A and 14A of the -side support shaft portion 13 and the other side support shaft portion 14 located on the suction side and the discharge side of the center shaft 12 are provided on the concave portions 15 and 16 side provided in the casing 1, respectively. Further, the water-side shaft sealing devices 17 and 17A are provided on the-side support shaft portion 13 and the other side support shaft portion 14, respectively.
And the tips 13B and 14B are respectively connected to the oil reservoir 1
It is rotatably supported by bearings 19, 19A provided on 8, 18A, and further, oil shaft sealing devices 20, 20A are provided between the water shaft sealing devices 17, 17A and the bearings 19, 19A. The gap between the recesses 15 and 16 and the base ends 13A and 14A is, for example, about 0.05 to 0.1 mm, which is used as a water shaft sealing portion. The other side support shaft portion 14 is subjected to rust prevention treatment. And the tip of the other-side support shaft portion 14
14B is connected via a joint (not shown) or the like so as to transmit the driving force of a prime mover 22 such as an engine or a motor.

On the other hand, the female screw rotor 3 is made of stainless steel, which is a rust-resistant metal, and has a rotor tooth 6 and a -side support shaft 24 and an other-side support shaft which project on both sides of the rotor tooth 6 (see FIG. 1). (Not shown) are integrally formed. And the support shaft part 24
Further, on the other side support shaft portion, a water shaft sealing device (not shown), a bearing (not shown), and the like are provided similarly to the above-mentioned-side support shaft portion 13. Accordingly, the rotational driving force of the rotary shaft 23 of the driving motor 22 is rotated by the rotation of the rotor tooth portion 5 of the male screw rotor 2 made of thermosetting resin from the central shaft 12 so that the rotor tooth portion 6 of the female screw rotor 3 made of stainless steel is rotated. Are directly engaged and driven.

In the drawing, reference numeral 27 denotes a jacket for cooling water 28 provided outside the cylinder portion 4. Next, the operation of the above configuration will be described. When the prime mover 22 is started, its rotating shaft 25
Is rotated, and the female screw rotor 3 is driven to rotate about the center shaft 12 by the rotation force of the rotation shaft 25. In the present embodiment, the male screw rotor 2 is started to rotate by the prime mover 22, but the female screw rotor shaft can be driven by the prime mover. As a result, the instantaneous load power applied at the time of starting the prime mover 22 can be reduced. That is, the male screw rotor 2 is made of a metal center shaft as described above.
Since the rotor tooth portion 5 made of a thermosetting synthetic resin is integrally formed on the outer periphery of 12, the specific gravity on the outer peripheral side of the male screw rotor 2 is extremely smaller than that of steel, so that the moment of inertia can be reduced. It is. Since the rotor teeth 5 and the rotor teeth 6 are directly meshed with each other, the rotational force is transmitted to the female screw rotor 3 through the rotor teeth 6, and the rotor shaft 3 and the other shaft 24 are connected. It is driven and rotated as the rotation center. At this time, since the rotor teeth 6 made of stainless steel mesh with the rotor teeth 5 made of the thermosetting synthetic resin, the two are well adapted to each other, so that galling occurs between the two. Never. In addition, the seal line formed by the contact between the rotor tooth portions 5, 6 can be reliably sealed. As a result, the air sucked from the suction port 7 through the suction passage 8 and the suction side opening 4A flows into the compression action space S surrounded by the rotor teeth 5, the rotor teeth 6, and the cylinder 4, and is compressed. Start. At this time, the water W is jetted from the water jet port 4C by the pressure difference between the receiver tank and the compression action space S, and the water W forms a water film on the rotor teeth 5, 6 and the cylinder 4 to form the compression action space S. Lubrication,
Cool and seal. After compressing the air to a predetermined pressure with the rotation of the screw rotors 2 and 3 in this way, when the compression action space S communicates with the discharge side opening 4B, the compressed air is discharged from the discharge side opening 4B together with the water W through the discharge side opening 4B. It is discharged from the discharge port 10 through 11. The compressed air and the water W discharged from the discharge path 11 are temporarily stored in a receiver tank, and the compressed air is supplied to various devices, and the water is circulated so as to be ejected from the water outlet 26 again. Further, when the internal pressure of the receiver tank rises to a predetermined pressure, the unloader valve 9 is closed and the driving motor 22 is stopped in response to the internal pressure of the receiver tank. On the other hand, when the internal pressure of the receiver tank decreases to a predetermined pressure, the unloader valve 9
, And the prime mover 22 is restarted.

As described above, the male screw rotor 2 is rotationally driven by the prime mover 22 and the female screw rotor 3 is rotated.
The female screw rotor 3 rotates and follows the rotation of the male screw rotor 2 to perform a compressing action, so that little drive torque is applied to the female screw rotor 3. Therefore, abnormal wear and seizure hardly occur at the contact portions of the rotor tooth portions 5 and 6. During operation of the compressor, the rotor teeth 5 and 6 become hot during the operation of the compressor. In particular, since the rotor teeth 5 are formed of synthetic resin, the heat received by the rotor itself is also better than the metal. In addition, the thickness of the rotor tooth portion 5 is large, and its strength can be sufficiently endured. On the other hand, the female rotor teeth 6 are made of stainless steel, and only rotate following the male screw rotor 2 as described above. Therefore, even if the rotor teeth 6 are thin, sufficient strength is obtained. Is secured.

As described above, in the above embodiment, the rotor tooth portion 5 of the male screw rotor 2 is formed of a thermosetting synthetic resin, and the female screw rotor 3 is formed of stainless steel which is a rust-resistant metal. Since the surface of the rotor tooth portion 5 of the male screw rotor 2 made of synthetic resin is softer than metal and has good conformability with metal, the rotor tooth portion 5 of the other female screw rotor 3 directly meshes with the rotor tooth portion 6 so as to rotate. However, since the female screw rotor 3 rotates following the male screw rotor 2, almost no driving torque is applied during operation, so that abnormal wear or seizure does not occur at the contact portion. Further, since the rotational force of the prime mover 22 is transmitted to the female screw rotor 3 (rotor tooth 6) via the male screw rotor 2 (rotor tooth 5) and is directly driven to rotate, the male and female screw rotors 2, 3 are synchronously rotated. There is no need for a timing gear for this purpose, so that the sealing line forming the compression action space S formed in the rotor teeth 5, 6 of the male and female screw rotors 2, 3 can be reliably sealed. In addition, the tooth portions of the rotor tooth portion 5 are thick, so that there is no danger of being thermally deformed.

On the other hand, the rotor tooth portion 6 of the female screw rotor 3
Is formed of stainless steel, so that seizure between the rotor teeth 5, 6 can be eliminated as described above, and the thickness of the rotor teeth 5 is larger than that of the male screw rotor 2. Even if the thickness is thin, the strength can be sufficiently maintained. Therefore, there is no deformation of the rotor teeth 6. As a result, there is no seizure of the rotor teeth 5, 6.

The male screw rotor 2 has a metal center shaft.
Since the rotor teeth 5 made of a thermosetting synthetic resin are integrally formed on the outer periphery of 12, the center shaft to which a rotational load is applied
12 has the mechanical strength, the thickness of the rotor tooth portion 5 is thick and has sufficient strength, and it is also manufactured at a lower cost compared to the case where it is formed by cutting out a thick metal material as in the past. it can. In addition, since the weight of the male screw rotor 2 can be reduced, the weight of the entire compressor can also be reduced.

The rotor tooth portion 5 of the male screw rotor 2
Is molded using a thermosetting synthetic resin to reduce the weight, the moment of inertia of the compressor can be reduced, and the instantaneous load power applied at the time of starting the driving motor 22 can be reduced.

The present invention is not limited to the above-described embodiment. For example, in the first embodiment, if the screw rotor tooth portion can secure a predetermined strength, either one of the male and female members is made of a thermosetting synthetic resin. Various modifications are possible, such as molding by a method. The female screw rotor is preferably a generally used alloy steel of nickel and chromium having a chromium content of 11% or more. However, the material is not limited thereto, and any material may be used as long as it is a rust-resistant material similar to the present material.

[0022]

According to the first aspect of the present invention, a male and female screw rotor meshing with each other is rotatably housed in a casing, and water is jetted into a compression working space to lubricate the space. In a water-lubricated screw compressor that performs cooling and sealing, at least the rotor teeth of one of the pair of screw rotors is formed of a thermosetting synthetic resin, and the other screw rotor is formed. Since at least the rotor teeth are formed of a rust-resistant metal, the rotor teeth of the pair rotate directly with the thermosetting synthetic resin and the metal, but the familiarity of both is good, and Since the sealing line of the rotor tooth portion can also be securely sealed, even a compressor using water having low viscosity and poor sealing performance as a lubricating liquid eliminates the need for a timing gear,
In addition, the sealability between the rotor teeth can be improved, and a high-performance water-lubricated screw compressor without gas leakage can be provided. In addition, since the rotor tooth portion of the male screw rotor is formed of a thermosetting synthetic resin, the rotor tooth portion has a large thickness and is not likely to be thermally deformed.

According to a second aspect of the present invention, the rotor teeth of the male screw rotor are formed of a thermosetting synthetic resin having excellent conformability, and the rotor teeth of the female screw rotor are formed of stainless steel. The rotor tooth portions of the male screw rotor and the rotor tooth portion of the male screw rotor and the casing (cylinder) have good conformability and the strength of the rotor tooth portion of the female screw rotor can be sufficiently maintained, so that there is no seizure between the rotor tooth portions. .

According to a third aspect of the present invention, in the male screw rotor, a rotor tooth portion made of the thermosetting synthetic resin is integrally formed on an outer periphery of a metal center shaft, so that a predetermined strength is provided by the metal center shaft. As a result, the male screw rotor itself can be manufactured at low cost. Furthermore, the weight of the male screw rotor having a thicker rotor tooth portion can be reduced, so that the weight of the entire compressor can be reduced.

According to a fourth aspect of the present invention, a male-female-paired screw rotor meshing with each other is rotatably housed in a casing, and water is jetted into a compression working space to lubricate, cool, and cool the space. In a water-lubricated screw compressor that performs sealing, the male screw rotor is integrally formed with a rotor tooth portion made of a thermosetting synthetic resin on the outer periphery of a metal center shaft, and the female screw rotor is made of stainless steel. The effect according to any one of claims 1 to 3, wherein the driving force of the driving motor is transmitted to a center axis of the male screw rotor, and the female screw rotor is driven to rotate by the male screw rotor. In addition, the weight of the male screw rotor can be reduced, so that the instantaneous load power applied at the time of starting the prime mover can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view around a female screw rotor showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Male screw rotor 3 Female screw rotor 4 5 Rotor tooth part 12 Center axis 22 Motor drive S Compression action space W Water

Claims (4)

[Claims] 1. A male-female pair of screw rotors meshing with each other are rotatably housed in a casing, and water is jetted into a compression working space to perform lubrication, cooling, and sealing in the space. Water-lubricated screw compressor
At least the rotor teeth of one of the pair of screw rotors are formed of a thermosetting synthetic resin, and at least the rotor teeth of the other screw rotor are formed of a rust-resistant metal. Water lubricated screw compressor. 2. The water-lubricated type according to claim 1, wherein rotor teeth of said male screw rotor are formed of a thermosetting synthetic resin, and rotor teeth of said female screw rotor are formed of stainless steel. Screw compressor. 3. The water-lubricated screw compressor according to claim 2, wherein said male screw rotor is integrally formed with a rotor tooth portion made of said thermosetting synthetic resin on an outer periphery of a metal center shaft. 4. A male and female screw rotor meshing with each other is rotatably accommodated in a casing, and water is jetted into a compression working space to lubricate, cool, and seal the space. Water-lubricated screw compressor
The male screw rotor is formed by integrally forming a rotor tooth portion made of a thermosetting synthetic resin on an outer periphery of a metal center shaft, the female screw rotor is formed of stainless steel, and a driving motor is mounted on a center shaft of the male screw rotor. To transmit the driving force of
A water-lubricated screw compressor, wherein the female screw rotor is driven to rotate by the male screw rotor.