JP5390478B2 - Screw steam machine - Google Patents

Description

  The present invention relates to a screw-type steam machine that compresses steam or converts the expansion force of steam into rotational force.

  In a screw-type steam machine using steam as a handling fluid, a shaft is sealed between a rotor chamber filled with steam and a lubricating oil chamber such as a bearing. Here, as a shaft seal structure used for a rotary machine such as a compressor, for example, those described in Patent Documents 1 and 2 are known.

  Patent Document 1 describes a shaft sealing technique in which a high-pressure liquid is pushed into a gap between a rotating shaft and a seal ring, and leak gas is pushed back by the pressure of the pushed-in liquid. Patent Document 2 describes a shaft sealing technique in which a seal gas is pushed into a gap between a rotating shaft and a seal ring, and a leak gas is pushed back by the pressure of the pushed seal gas.

JP-A-53-81868 JP-A-62-124364

  The shaft sealing techniques described in Patent Documents 1 and 2 both push back leak gas with a fluid. In the case of this shaft seal technology, attention must be paid to the relationship between the pressure of the fluid to be pushed in and the pressure of the handling fluid (compressed fluid or expanded fluid). The pressure of the fluid to be handled varies, and the pressure varies depending on the equipment specifications. If the pressure of the fluid to be pushed in is too higher than the pressure of the fluid to be handled, the flow rate of the pushing fluid passing through the gap between the rotating shaft and the seal ring becomes excessive, which may cause a problem. Conversely, when the pressure of the fluid to be pushed in is lower than the pressure of the handling fluid, the shaft seal becomes insufficient and the handling fluid leaks.

  On the other hand, in a screw-type steam machine using steam as a handling fluid, if leaked steam or its condensed water enters the lubricating oil chamber, there is a possibility of causing deterioration of the lubricating oil or poor lubrication of the bearing. For this reason, it is necessary to ensure that the leaked steam does not enter the lubricating oil chamber.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a screw provided with a shaft seal structure that can prevent leaked steam from entering the lubricating oil chamber irrespective of the pressure of the steam that is the handling fluid. Is to provide a steam machine.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have sequentially made a first annular seal member, a second annular seal member, and a third annular seal member from the rotor chamber (steam chamber) side toward the lubricating oil chamber side. The above problem could be solved by arranging the condenser in the first hole communicating with the first seal space between the first annular seal member and the second annular seal member. Based on this finding, the present invention has been completed.

That is, the present invention is housed in a rotor chamber formed in a housing and compresses steam or converts the expansion force of steam into rotational force, the rotor chamber, and a lubricating oil chamber formed in the housing. Between the rotor chamber side and the lubricating oil chamber side, the first annular seal member, the second annular seal member, and the third annular seal member, which are arranged in order, are formed on the housing, A first hole communicating with the first seal space between the annular seal member and the second annular seal member, and a second hole formed in the housing between the second annular seal member and the third annular seal member. and communicating the seal space, and a second hole open to the atmosphere, wherein attached to the first hole, screw steam comprising a condenser for condensing the steam leaked to the first seal space from the rotor chamber side, the It is 械.

  According to this configuration, the leak steam condenses in the condenser, whereby the pressure in the first seal space decreases, and the leak steam escapes from the first seal space via the first hole. This prevents leakage steam from entering the lubricating oil chamber. Furthermore, since the pressure in the first seal space is lower than the pressure in the second seal space due to condensation of leak vapor, air tends to enter the first seal space from the second seal space. As a result, the air plays the role of pushing back the leaked steam that tends to exceed the second annular seal member toward the lubricating oil chamber, and this also prevents the leaked steam from entering the lubricating oil chamber.

  If the capacity of the condenser is too large, only the amount of leaked steam is increased, and the other parts of the screw-type steam machine are not adversely affected. That is, if the condenser capacity (condensation capacity) is provided with a certain margin, it is possible to reliably prevent the leakage steam from entering the lubricating oil chamber regardless of the pressure of the steam that is the handled fluid.

  In the present invention, the condenser has a main body container to which steam is supplied and a refrigerant pipe installed in the main body container, and a drain trap is attached to an outlet of the main body container. preferable.

  According to this configuration, condensed water is accumulated in the main body container, and air can be prevented from flowing into the first hole from the outside due to the accumulated condensed water. As a result, the first seal space can be at a lower pressure. Moreover, since only the condensed water is discharged from the condenser, the treatment of the leaked steam becomes unnecessary.

  Further, in the present invention, the condenser has a main body container to which a refrigerant is supplied and a steam pipe installed in the main body container, and an ejector for sucking the steam and the condensed water is an outlet of the steam pipe. It is preferable that it is attached to.

  According to this configuration, the first seal space can be set to a lower pressure by forcibly sucking the steam and its condensed water with the ejector. Moreover, the liquid level management in the main body container of the condenser is not particularly required. Furthermore, since it is not necessary to be particularly concerned about the liquid level fluctuation in the main body container of the condenser, the capacity of the main body container can be reduced, that is, a compact condenser can be obtained.

  Furthermore, in this invention, it is preferable to provide the air supply means attached to the said 2nd hole, and supplying pressurized air to the said 2nd seal space.

  According to this configuration, the pressure in the second seal space can be increased. By increasing the pressure in the second seal space, the action of trying to push back the leaked steam that attempts to exceed the second annular seal member toward the lubricating oil chamber side is further improved.

  According to the present invention, in a screw-type steam machine using steam as a handling fluid, it is possible to prevent leakage steam from entering the lubricating oil chamber regardless of the pressure of the steam.

It is a sectional side view showing the screw type steam compressor concerning a 1st embodiment of the present invention. It is a detailed sectional side view which shows a part of screw-type steam compressor which concerns on 2nd Embodiment of this invention. It is a detailed sectional side view which shows a part of screw-type steam compressor which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, an example in which the shaft seal structure according to the present invention is applied to a screw-type steam compressor that compresses steam is shown. However, the shaft seal structure according to the present invention converts the expansion force of steam into rotational force. The present invention can also be applied to a screw type steam expander (screw expander).

(First embodiment)
As shown in FIG. 1, the screw-type steam compressor 1 includes a pair of male and female screw rotors 3, a rotor shaft 4 provided coaxially with one rotor (male rotor) of the screw rotor 3, and the rotor shaft 4 rotating. A motor (not shown). The screw rotor 3 is accommodated in a rotor chamber 5 formed in the housing 2. The housing 2 is provided with a suction passage 13 for supplying steam to be compressed to the rotor chamber 5 and a discharge passage 14 for discharging the steam compressed in the rotor chamber 5 by the screw rotor 3. The steam supplied from the suction channel 13 is compressed to 0.5 MPa, for example, by the screw rotor 3 and then discharged from the discharge channel 14.

  Note that a screw-type steam compressor having one screw rotor (single rotor) may be used instead of the pair of male and female screw rotors 3 (double rotor).

  The housing 2 is provided with a lubricating oil chamber 23. The lubricating oil chamber 23 accommodates the bearing 10 that supports the rotor shaft 4 and is filled with lubricating oil. Here, in the space formed between the lubricating oil chamber 23 and the rotor chamber 5, the first annular seal member 6, the second annular seal member 7, from the rotor chamber 5 side toward the lubricating oil chamber 23 side, And the 3rd annular seal member 8 is arranged at predetermined intervals in order.

  A seal space is formed by the first annular seal member 6, the second annular seal member 7, and the third annular seal member 8 that are disposed in the gap between the rotor shaft 4 and the housing 2. A space between the first annular seal member 6 and the second annular seal member 7 is referred to as a first seal space 11, and a space between the second annular seal member 7 and the third annular seal member 8 is a second seal space. Let's call it 12.

  Here, the first annular seal member 6 disposed at a position closest to the rotor chamber 5 is preferably a non-contact type seal member. This is because high-temperature leak steam from the rotor chamber 5 tends to enter the gap between the first annular seal member 6 and the rotor shaft 4 and high-temperature leak steam hits the first annular seal member 6 itself. When a contact-type seal member is used as the first annular seal member 6, the deterioration rate is large, and the seal function is reduced in a short period of time.

  The third annular seal member 8 disposed at a position farthest from the rotor chamber 5 (closest to the lubricating oil chamber 23) is a contact-type seal member or a non-contact-type seal member. The second annular seal member 7 installed between the first annular seal member 6 and the third annular seal member 8 is a non-contact type seal member.

  Examples of the non-contact seal member include a labyrinth seal and a visco seal. Examples of the contact seal member include a lip seal and an O-ring. The first annular seal member 6, the second annular seal member 7, and the third annular seal member 8 are, for example, a labyrinth seal, a visco seal, and a lip seal, respectively.

  The housing 2 has a first hole 15 for communicating the outside with the first seal space 11 and a second hole 16 for communicating the outside and the second seal space 12.

  FIG. 1B is a detailed view of part A in FIG. As shown in FIG. 1B, the condenser 9 is attached to the end of the first hole 15 on the side opposite to the first seal space 11 via a pipe 17. 1A and 1B are schematic views for explaining the present invention, and are not drawings of actual products. The pipe 17 is for showing that the first hole 15 and the condenser 9 are connected by a pipe, and does not show an actual pipe as it is. The second hole 16 is open to the atmosphere.

  The condenser 9 includes a main body container 9a to which steam is supplied and a refrigerant pipe 9b installed in the main body container 9a. A drain trap 18 is attached to the discharge port 9c of the main body container 9a. The drain trap 18 is for accumulating condensed water inside the main body container 9a and sealing between the outside (atmosphere space) and the first seal space 11 with the condensed water. For example, water flows through the refrigerant pipe 9b. The main body container 9a has a cylindrical shape, for example.

(Shaft seal principle)
A part of the high-temperature steam compressed in the rotor chamber 5 by the screw rotor 3 leaks into the first seal space 11 from the gap between the rotor shaft 4 and the first annular seal member 6. The leaked steam (leaked steam) leaked into the first seal space 11 flows into the main body container 9 a of the condenser 9 through the first hole 15 and the pipe 17. The leaked vapor is cooled and condensed by water flowing through the refrigerant pipe 9b. By condensing the leaked vapor, its volume is drastically reduced, and as a result, the pressure in the first seal space 11 is reduced to atmospheric pressure or lower. As a result, leaked steam leaking from the gap between the rotor shaft 4 and the first annular seal member 6 escapes from the first seal space 11 to the main body container 9a of the condenser 9 via the first hole. As a result, intrusion of leaked steam into the lubricating oil chamber 23 is prevented. Further, since the pressure in the first seal space 11 is reduced to the atmospheric pressure or lower, air enters the first seal space 11 from the second seal space 12 that is controlled to the atmospheric pressure. The air plays a role of pushing back the leaked steam that tries to leak from the gap between the rotor shaft 4 and the second annular seal member 7 toward the lubricating oil chamber 23, and this also causes the leaked steam to enter the lubricating oil chamber 23. Intrusion is prevented.

  A drain trap 18 is attached to the condenser 9. The drain trap 18 accumulates condensed water in the main body container 9a of the condenser 9, and it is possible to prevent air from flowing into the first hole 15 from the outside through the main body container 9a due to the accumulated condensed water. As a result, the first seal space 11 can be set to a lower pressure. Further, since only the condensed water is discharged from the condenser 9 by the drain trap 18 (not discharged as steam gas), it is not necessary to treat leaked steam.

  In the shaft sealing technology in which leak gas is pushed back with a shaft sealing fluid as described in Patent Documents 1 and 2, if the pressure of the shaft sealing fluid to be pushed in is too higher than the pressure of the handling fluid (for example, steam), the rotating shaft The flow rate of the shaft seal fluid that passes through the gap between the seal ring and the seal ring becomes excessive, which may cause a problem. Conversely, if the pressure of the shaft seal fluid is lower than the pressure of the handling fluid, the shaft seal becomes insufficient and the handling fluid leaks. However, in the case of the present invention, if the capacity (condensation capacity) of the condenser 9 is too large, only the amount of leaked steam is increased, which adversely affects other parts of the screw-type steam compressor. Will not be affected. That is, if the capacity of the condenser 9 (condensing capacity) is given a certain margin, it is possible to reliably prevent the leakage steam from entering the lubricating oil chamber 23 regardless of the pressure of the steam that is the handled fluid.

(Second Embodiment)
A screw-type steam compressor 201 according to the second embodiment will be described with reference to FIG. The difference between the screw-type steam compressor 201 of the second embodiment and the screw-type steam compressor 1 of the first embodiment is that the structure of the condenser and the ejector 22 instead of the drain trap 18 are used in the second embodiment. It is a point. In the second embodiment, leak steam and its condensed water are forcibly sucked by the ejector 22.

  As shown in FIG. 2, the condenser 20 attached to the first hole 15 via the pipe 17 includes a main body container 20a to which a refrigerant is supplied, and a steam pipe 20b installed in the main body container 20a. It becomes. The refrigerant supplied to the main body container 20a is, for example, water, and the main body container 20a has a cylindrical shape, for example. The steam pipe 20 b in the main body container 20 a communicates with the pipe 17, and the discharge port is attached to the ejector 22 through the pipe 21.

  Note that the pipe 17, the steam pipe 20b, and the pipe 21 are connected in this order from the upstream side, and the pipe 17 and the main body container 20a are not in communication. Similarly, the main body container 20a and the pipe 21 are in communication. Not done. The second hole 16 is open to the atmosphere as in the first embodiment.

  The ejector 22 includes a main body 22a and a nozzle 22b having a tip inserted into the main body 22a. The main body 22a has a cylindrical shape, for example. A fluid such as air or water is configured to be ejected from the tip of the nozzle 22b into the main body 22a. The inside of the main body 22a becomes negative pressure by the fluid ejected from the tip of the nozzle 22b, and the leaked steam and its condensed water are forcibly sucked.

  According to the present embodiment, the first seal space 11 can be set to a lower pressure by forcibly sucking the leaked steam and its condensed water with the ejector 22. Further, in the first embodiment, it is necessary to manage the liquid level in the main body container 9a of the condenser 9 for water sealing, but in the case of this embodiment, the method of forced suction by the ejector 22 is used. , No water seal required. That is, liquid level management in the condenser 20 is not necessary. Further, in the case of the present embodiment, unlike the first embodiment, since there is no need to be particularly concerned about the liquid level fluctuation in the main body container of the condenser, the capacity of the main body container 20a can be reduced, and the compact condenser 20 and can do.

(Third embodiment)
A screw-type steam compressor 301 according to a third embodiment will be described with reference to FIG. The screw-type steam compressor 301 of this embodiment has an air supply means 19 attached to the second hole 16 provided in the housing 2 of the screw-type steam compressor 1 of the first embodiment.

  The air supply means 19 includes an air pipe 18 and a regulator 19 attached to the air pipe 18. The regulator 19 includes a pressure reducing valve, a mist separator, a filter, and the like. Air from an air compressor (not shown) is supplied to the second seal space 12 by the air supply means 19 through the second hole 16. Leak that tries to leak from the gap between the rotor shaft 4 and the second annular seal member 7 to the lubricating oil chamber 23 side by slightly raising the pressure in the second seal space 12 by the air from the air supply means 19. Push steam back. According to the present embodiment, when the action of trying to push back the leaked steam that attempts to exceed the second annular seal member 7 toward the lubricating oil chamber 23 is returned to the rotor chamber 5 side (the second hole 16 is It is better than when the atmosphere is open.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. .

1: screw type steam compressor 2: housing 3: screw rotor 4: rotor shaft 5: rotor chamber 6: first annular seal member 7: second annular seal member 8: third annular seal member 9: condenser 11: first 1 seal space 12: second seal space 15: first hole 16: second hole 18: drainage trap 23: lubricating oil chamber

Claims (4)

A screw rotor housed in a rotor chamber formed in the housing and compressing the steam or converting the expansion force of the steam into a rotational force;
A first annular seal member, a second annular seal member, and Three annular seal members;
A first hole formed in the housing and communicating with a first seal space between the first annular seal member and the second annular seal member;
Formed in the housing, and communicates with the second seal a space between the third annular sealing member and the second annular sealing member, and a second hole that has been opened to the atmosphere,
A condenser attached to the first hole for condensing steam leaked from the rotor chamber side to the first seal space;
A screw-type steam machine. The screw-type steam machine according to claim 1,
The condenser has a main body container to which steam is supplied, and a refrigerant pipe installed in the main body container,
A screw-type steam machine, wherein a drain trap is attached to an outlet of the main body container. The screw-type steam machine according to claim 1,
The condenser has a main body container to which a refrigerant is supplied, and a steam pipe installed in the main body container,
A screw-type steam machine, wherein an ejector for sucking steam and its condensed water is attached to an outlet of the steam pipe. The screw-type steam machine according to any one of claims 1 to 3,
A screw-type steam machine comprising an air supply means attached to the second hole and configured to supply pressurized air to the second seal space.

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