JPH0747958B2 - Eyebrow type 2-axis multi-stage vacuum pump with internal cleaning - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-leaf two-axis multi-stage vacuum pump used as a volley type vacuum pump for vacuum packing foods and recovering vapor in chemical gas.

(Prior art and problems) Oil-lubricated vacuum pumps are often used for vacuum packing of food and recovery of vapor in chemical gas. Since this vacuum pump is a type that requires oil mixing, the scattering of oil mist is a pollution. Also, the viscous substance mixed in the gas becomes a mist that is liquefied due to the degree of vacuum, temperature, etc.
There is a serious defect that oil deterioration is caused by the circulating use of oil. For this reason, a dry type eyebrow type two-axis multi-stage vacuum pump is often used. However, since this vacuum pump is a dry type mist sucked from food, chemical gas, etc., it may adhere to the inner surface of the rotor or the casing to cause a problem that the pump shaft cannot rotate. There is a model that mixes and sucks to wash the liquid, and the washing liquid is impacted by the concave and convex corresponding surfaces of the pair of rotors to cause a binding phenomenon, the washing liquid becomes a high pressure liquid and plunges into the seal box on the housing side, There are even unexpected troubles such as exhaustion of seals, penetration of bearings and timing gears, and deterioration of bearing grease and timing gear oil by cloudiness.

In order to prevent this defect, a screen is provided at the suction port to collect the suction mist, but if a large amount of mist is mixed, it will be a great resistance, so the rough mist collection is currently done. Is.

However, there is no method other than cleaning to remove substances that are separated from minute sludge and chemical gas and adhered to the inner surface of the dry vacuum pump.

(Problems to be Solved by the Invention) In the present invention, when the pump liquid is transmitted through the pump shaft and oozes into the housings on both sides due to the pressure difference, all of the entrained liquid is rotated in the respective seal boxes of the final stage housing and the initial stage housing. It is an object of the present invention to solve the problem that the structure is shaken off together with it and that the compression loss is not generated.

(Means for Solving Problems) The eyebrow type two-axis multistage vacuum pump capable of cleaning the inside of the present invention meets the above-mentioned object, and the compressed gas moving path between each stage is an internal or external type. In a 3-leaf Mayu type two-shaft multi-stage vacuum pump, a discharge side cooling communication passage or an atmosphere communication passage is connected to the first seal box of the final stage housing (L), and the communication passage is compressed from the first seal box to the final stage. A first pressure liquid cut-off ring for preventing inclusion of cleaning liquid is provided on the pump shaft passing through the neck portion of the seal box while opening in the gas compression region of the chamber, and the second seal box of the housing (R) on the first stage side is provided. A pump passage that communicates with a communication passage that communicates with the suction side (cool air) of the second stage, opens the communication passage from the second seal box to the gas compression region of the first stage, and passes through the neck portion of the second seal box. Doo relates inner washable cocoon-screw multistage vacuum pump, characterized in that a ring shaking-off second pressure fluid cleaning solution bind-prevention.

It was experimentally confirmed that it is advantageous that the suction of the first stage is performed from above, the discharge of the final stage is downward, the amount of the binding liquid is reduced by gravity, and the falling speed of the cleaning liquid removal is accelerated. Incidentally, the high liquid pressure of the binding liquid of the cleaning liquid is estimated to be about ² to 3 kg / cm ² .

(Embodiment) FIG. 1 is a vertical sectional view of a vacuum pump of the present invention, FIG. 2 is an enlarged vertical side view of a housing L of FIG. 1, and FIG.
It is a flow sheet of the A line cutting state. (The number of stages can be changed depending on the gas quality, etc.) In the figure, 2 is the casing of the 3-leaf 3-stage eyebrows vacuum pump 1,
Reference numeral 3 denotes a final stage (third stage) housing (L), and 4 denotes a first stage housing (R). ) Three-stage eyebrow type vacuum pump 1 has first stage I, second stage II, third stage
A compression chamber of III is provided, and a pair of three-leaf type rotors 5 and 5 are fitted in each chamber, and the front chamber discharges into partition walls 7a and 8a between stages through which pump shafts 6 and 6 common to each rotor are passed. The compressed gas moving paths 7 and 8 are provided to connect the outlet and the suction port of the rear chamber.
Reference numeral 9 is a suction port of the compression chamber of the first stage I, and a cleaning liquid supply port is provided inside. Reference numeral 10 is a discharge port of the compression chamber of the third stage III, 11 is a heat exchange plate constituting an outer wall of a portion which communicates the discharge port of the compression chamber of the first stage I and the compressed gas moving path 7, and 12 is a second stage II. Is a heat exchange plate forming an outer wall of a portion that communicates the discharge port of the compression chamber with the compressed gas compression moving passage 8, and 13 is a portion of the portion that communicates the compressed gas moving passage 8 with the suction port of the compression chamber of the third stage III. The heat exchange plate constituting the outer wall, 14 is a cooler outside the heat exchange plate 11, 15 is the heat exchange plate 12
The outer cooler 16 is a cooler outside the heat exchange plate 13.

In the present embodiment, the compressed gas transfer passages 7 and 8 are integrally molded with the casing. However, the compression transfer passage pipes may be inserted from the outside of the casing 2.

An intercooler 23 is installed at the discharge port 10 of the third-stage compression chamber III.
The discharge side cooling communication passage 22 (or the atmosphere communication passage 22a that does not communicate with the discharge 10) is connected to the housing connection port 18 that communicates with the first seal box 17 provided in the housing (L) 3. The first seal box 17 is provided with the same number as the pump shafts 6, 6, and this is the neck portion N. The neck portion N is communicated with the connection port 18 and the cleaning liquid is mixed into the pump shaft 6 passing through the neck portion N. The first pressure liquid shake-off ring 19 for prevention is fitted and fixed, the seal ring 20 is provided subsequently thereto, the bearing 21 is attached to the outside of the neck portion N, and the short pipe portion opened to the outer periphery of the first seal box 17 is further provided.
24 is communicated with an opening 25 (see FIG. 3) formed in the side plate of the compression chamber of the third stage III. The cleaning liquid collected by the seal ring 20 is removed from the drain hole. The opening 25 is provided in the gas compression region IIIa of the compression chamber of the final stage (third stage) III. Two seal boxes 17 and 17 'are provided as shown in FIG. 3 and communicate with each other through a connection hole 17a.

The housing (R) 4 has a housing connection port 18 'and a second seal ring 20' having a neck portion N '.
8 ', 2nd pressure liquid shaker 1 fitted on pump shaft 6
9 ', a seal ring 20', and a bearing 21 'are provided in the same manner as the housing (L), and the housing connection port 18' has a second stage.
A short pipe that communicates with the suction port of the compression chamber of II or the compressed gas moving path 7 adjacent to the port and also connects with the cooling communication path 26 through which the intercooler 27 is inserted, and opens to the outer periphery of the second seal box 17 '. Portion 24 'communicates with opening 25' formed in the side plate of the first stage I compression chamber. The opening 25 'is provided on the side plate of the first-stage compression chamber, but is at the same position as the opening 25 in FIG.

The seal rings 20 and 20 'described above have the same sealing effect even if a known mechanical seal or an oil seal is used. 33 is a pulley fixed to one pump shaft, 35
Is a timing gear cover outside the first stage housing (R) 4.

In the present embodiment, since the three-leaf type three-stage eyebrows type vacuum pump 1 which is a multi-stage type has a vacuum degree of the suction port 9 of about 1 Torr,
The cleaning liquid supplied to the port 9 is immediately misted and sequentially compressed in the compression chambers of the third stage III, the second stage II, and the first stage I, and the coolers 14 to 16 or Is cooled by a cooling device in place of the above, and temperature rise due to compression is suppressed. Then, it is compressed in the compression chamber of the third stage III, and the discharge port 10
Although the compressed gas that is discharged from the outside to the outside air has the highest temperature, a part of the compressed gas is cooled by the intercooler 23 in the discharge side cooling communication passage 22 and supplied to the housing connection port 18, or the above-mentioned connection from the atmosphere communication passage 22a. The cooling air supplied to the port 18 cools the first seal box 17 of the housing (L) 3 forming the neck portion N, and even if there is a cleaning liquid mist ejected to the first seal box 17 along the pump shaft 6, (1) The liquid is shaken off by the pressure liquid shaking ring 19, and the shaking liquid is mixed to move the gas from the short pipe portion 24 to the third stage III.
Since it is sent to the opening 25 of the compression chamber of the (final stage) and discharged from the discharge port 10 again, the seal material for the shaft seal such as the seal ring 20 in the first seal box 17, the bearing 21, etc.
It is possible to prevent wear and deterioration due to the cleaning liquid mist. The first-stage housing (R) 4 is also operated in the same manner as the last-stage housing (L) 3, and in particular, the cold gas communication passage 26 allows the compressed gas moving path 7 of the second-stage chamber II to move. Since the gas is sampled, cooled by the intercooler 27 and connected to the housing connection port 18 ', the cleaning liquid mist ejected along the pump shaft 6 to the second seal box 17' is discharged by the second pressure liquid shaking ring 19 '. It is sent out from the short pipe portion 24 'to the opening 25' on the compression side of the compression chamber I in the same manner as the final stage housing (L) 4, and the outside air is collected and sent to the housing connection port 18 '. Since it is not a thing, there is no pressure loss.

(Operation and effect) When a multi-stage vacuum pump is operated at a vacuum degree of about 1 Torr and a cleaning liquid such as water is poured, it immediately becomes a mist (the vaporization vacuum degree is 50 Torr).
Therefore, it is ideal to carry out at the end of the work, but it may be poured during the work, in which case a large amount of mist of cleaning liquid will be in the compression chamber of each stage due to the stagnation of the injection pipe or the degree of vacuum. Since the liquid may flow in and the liquid is incompressible even in a small amount, it is possible to make a third gap between the concave and convex portions of the rotors 5, 5.
As shown in the figure, the cleaning liquid that has lost the escape area is confined and a so-called confinement phenomenon occurs with a continuous explosion sound. At that time, the high pressure liquid is transmitted along the pump shaft to the housing (L).
(R) is projected into the first and second seal boxes and repeated to damage the seal materials such as the seal rings 20 and 20 'and to cause the lubricating oil component of the bearings 21 and 21' to be clouded and deteriorated. According to the present invention, even if a binding phenomenon occurs and the first and second seal boxes 17 and 17 'are projected, the discharge side cooling communication passage 22 or the atmosphere communication passage 22a or the cool air communication passage is provided in the boxes 17 and 17'. Since the 26 are communicated with each other, the mist-like cleaning liquid protruding into the first and second seal boxes 17 and 17 'is quickly and sufficiently cooled due to the binding phenomenon, and the first and second pressure liquid shaking rings 19, It is shaken off by 19 'and sent from the short pipe part etc. to the openings 25, 25' and atomized to prevent damage to the sealing materials such as the seal rings 20 and 20 'and deterioration of the bearings 21 and 21', and to prevent the multistage eyebrows. This is effective in maintaining the performance of the mold vacuum pump 1.

[Brief description of drawings]

1 is a vertical sectional view of the vacuum pump of the present invention, FIG. 2 is an enlarged vertical side view of the housing L of FIG. 1, and FIG. 3 is FIG.
It is a flow sheet of the A line cutting state. I ... First stage, II ... Second stage III ... Third stage, IIIa ... Compression region 1 ... 3-leaf type 3-stage eyebrow vacuum pump 2 ... Casing, 3 ... Final stage housing (L) 4 ... 1st stage housing (R) 5 ... 3-leaf rotor, 6 ... Pump shaft 7, 8 ... Compressed gas moving path, 9 ... Suction port 10 ... Discharge port, 11, 12, 13 ...... Heat exchange plates 14, 15, 16 ...... Coolers 17, 17 '...... First and second seal boxes 18, 18' ...... Housing connection port N, N '...... Neck part 19, 19 '…… 1st and 2nd pressure liquid shaking ring 20, 20' …… Seal ring 21, 21 ′ …… Bearing 22 …… Discharge side cooling communication passage, 22a …… Atmosphere communication passage 23 …… Intercooler 24, 24 ′ …… Short pipe part 26 …… Cold air passage, 27 …… Intercooler

Claims (1)

[Claims] 1. In a three-leaf eyebrow type two-axis multi-stage vacuum pump in which a compressed gas moving path between each stage is built-in or an exterior type, a discharge side cooling communication passage or a first seal box of a final stage side housing (L) is provided. An atmosphere communication passage is connected, the communication passage is opened from the first seal box to the gas compression region of the final stage compression chamber, and the first pressure liquid vibration for preventing the inclusion of the cleaning liquid on the pump shaft passing through the neck portion of the seal box. A cut ring is provided, and a communication passage that communicates the suction side (cool air) of the second stage is communicated with the second seal bock of the housing (R) on the first stage side, and the communication passage is further extended from the second seal bock to the first side. A two-way eyebrow type with internal washing capable of opening to the gas compression region of the stage and having a second pressure liquid shaking ring for preventing the inclusion of the washing liquid on the pump shaft passing through the neck portion of the second seal box. Multi-stage true Empty pump.