JP6210499B2 - How to prevent bearing condensation on rotary joints - Google Patents

Description

  The present invention relates to a bearing condensation prevention method for a rotary joint.

  In Patent Document 1, in a rotary joint of a rotary filling device that fills a container with liquid or the like, an oil-free bearing that pivotally supports a rotating portion on a fixed portion of the rotary joint, to a rotation control panel that rotates together with the rotating portion. A bearing dew condensation prevention device for a rotary joint is disclosed in which a piping system is configured so that a part of the supplied dry air is branched and supplied from the piping system.

  According to this rotary joint bearing dew condensation prevention device, by supplying dry air to the oilless bearing that pivotally supports the rotating part to the fixed part of the rotary joint, the oilless bearing is brought into a positive pressure state with dry air. High humidity humidity prevents air from entering, prevents condensation and prevents rust from occurring in oil-free bearings. In addition, a part of the dry air supplied to the rotation control panel that rotates with the rotating part is connected to the piping. By configuring the piping system so as to be branched and supplied from the system, the cost of the dry air supply piping device to the oil-free bearing can be suppressed.

Japanese Patent No. 5208908

  In the case of Patent Document 1, if the supply of dry air to the oil-free bearing is stopped, high-humidity air enters the oil-free bearing, condensation may occur, and the oil-free bearing may be rusted. Therefore, it is necessary to always supply dry air to the oil-free bearing regardless of the operating state of the rotary filling device, which is not preferable from the viewpoint of energy saving. Further, since the rotary joint has a piping system, the internal structure becomes complicated and the apparatus cost increases.

  The present invention has been made in view of the above problems, and provides a method for preventing bearing condensation in a rotary joint that does not increase the cost of the apparatus and that can save energy because the internal structure of the rotary joint is not complicated. For the purpose.

Thus, according to the present invention, a fixed shaft and a rotary shaft that are coaxially arranged, a mechanical seal that allows the fixed shaft and the rotary shaft to slide in a rotation direction about an axis, and the rotary shaft A rotary having a bearing attached to an outer peripheral surface and a housing connected to the fixed shaft so as to form a bearing chamber for housing the bearing, the housing having a filling port and a discharge port communicating with the bearing chamber At the joint,
Provided is a method for preventing bearing dew condensation on a rotary joint, in which grease is filled in the bearing chamber by a pushing force of compressed dry air, and then the bearing chamber is sealed.

  According to the present invention, when the bearing chamber is filled with grease during manufacture or overhaul of the rotary joint, the grease is filled in the grease storage case of the grease gun, and compressed dry air is supplied to the grease gun to supply the grease. Extrude into the alling chamber and fill. At this time, the existing air in the bearing chamber is pushed out by the grease and dry air.

Therefore, compared to the case where grease is filled into the bearing chamber with compressed air from which moisture has not been sufficiently removed, the amount of moisture in the bearing chamber is significantly reduced in the present invention, and condensation in the bearing chamber is reduced. Generation of rust on the bearing due to generation and condensation can be prevented.
In addition, the viscosity of the grease in the bearing chamber is reduced due to condensation, and leakage of the reduced viscosity grease from the bearing chamber can be prevented. In particular, in a rotary joint that handles food and drink, since leakage of grease may be mixed into food and drink, the advantage of preventing such grease from being mixed into food and drink is great.

  Furthermore, according to the present invention, as in Patent Document 1, a piping system that circulates dry air inside the rotary joint is provided, and there is no increase in apparatus cost and energy cost such as constantly supplying dry air to the piping system, It can also save energy.

It is a partial cross section front view which shows the rotary joint with which the bearing condensation prevention method of this invention is performed. (A) is a plug, (B) is a grease nipple, (C) is a relief nipple, and (D) is a side view which shows a male coupler used in the bearing dew condensation prevention method of the rotary joint of the present invention. It is a side view which shows the female coupler which connects with the male coupler of FIG.2 (D) so that attachment or detachment is possible. It is a side view which shows the grease gun used with the bearing dew condensation prevention method of the rotary joint of this invention. It is a conceptual diagram explaining the bearing dew condensation prevention method of the rotary joint of this invention.

The bearing dew condensation prevention method of the rotary joint of the present invention includes a fixed shaft and a rotary shaft arranged coaxially, a mechanical seal that allows the fixed shaft and the rotary shaft to slide in a rotational direction centered on an axis, A bearing attached to an outer peripheral surface of the rotary shaft; and a housing connected to the fixed shaft so as to form a bearing chamber for housing the bearing, the filling port and the exhaust communicating with the bearing chamber. In rotary joints with outlets,
The bearing chamber is filled with grease by a compressed dry air pushing force, and then the bearing chamber is sealed.

  In the present invention, “dry air” refers to air produced by passing compressed air from which moisture has been removed to some extent by a compressor through a dryer and further removing moisture. Specifically, the humidity of the dry air of the present invention is preferably 15% or less, more preferably 11% or less, and particularly preferably 8% or less, at a temperature of 10 to 35 ° C. and atmospheric pressure. In addition, although it does not specifically limit as a dryer to be used, For example, the sterilization dryer (form: D22A-MG-1) by Fukuhara Co., Ltd. is mentioned.

The bearing condensation prevention method of the rotary joint of the present invention may be performed as follows.
(1) Before filling the bearing chamber with grease, the air in the bearing chamber may be replaced with dry air.
In this way, the inside of the bearing chamber can be pre-dried with dry air, so that the moisture content in the sealed bearing chamber filled with grease with dry air can be further reduced, and condensation occurs. It is possible to enhance the effect of preventing the occurrence of rust on the bearing due to condensation and the leakage of grease from the bearing chamber due to condensation.

(2) A grease nipple is attached to the filling port, and a relief nipple that is opened when a predetermined pressure is exceeded is attached to the discharge port, and then compressed dry air is applied to the filling port via the grease nipple using a grease gun. In addition, grease may be filled.
If it does in this way, the bearing dew condensation prevention work of a rotary joint can be performed quickly. In particular, after the air in the bearing chamber is replaced with dry air, it is possible to proceed to the work of immediately filling the grease with dry air, so that the outside of the bearing chamber filled with dry air contains a lot of moisture. Can be suppressed.

(3) You may provide a slipper seal in the contact part with the outer peripheral surface of the said rotary shaft in the said bearing chamber.
Normally, a seal material is provided at the contact portion of the bearing chamber with the outer peripheral surface of the rotary shaft, and the seal material prevents leakage of grease from the inside of the bearing chamber. However, the seal has excellent wear resistance and durability. By using a slipper seal which is a material, leakage to the outside can be prevented even if the grease in the bearing chamber is reduced in viscosity due to moisture.

(4) The dry air may be sterilized.
In this way, since the growth of bacteria in the bearing chamber can be effectively suppressed, it is particularly suitable for a rotary joint for food.

  Hereinafter, embodiments of a bearing condensation prevention method for a rotary joint according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a partially sectional front view showing a rotary joint in which the bearing dew condensation prevention method of the present invention is performed, and FIG. 2 is used in the bearing dew condensation prevention method of the rotary joint of the present invention. ) Is a grease nipple, (C) is a relief nipple, and (D) is a side view showing a male coupler. 3 is a side view showing a female coupler removably connected to the male coupler of FIG. 2D, and FIG. 4 is a side view showing a grease gun used in the bearing dew condensation prevention method of the rotary joint of the present invention. It is.

<About Rotary Joint>
First, an example of a rotary joint as an object on which the bearing condensation prevention method of the present invention is performed will be described.
As shown in FIG. 1, the rotary joint 1 according to the first embodiment includes a pipe-shaped fixed shaft 10 and a pipe-shaped rotary shaft 20 arranged on the same axis P, and the fixed shaft 10 and the rotary shaft 20 are centered on an axis P. And a housing 50 connected to the fixed shaft 10 so as to form a bearing chamber 50a for housing the bearing 40, and a mechanical seal 30 that is slidable in the rotational direction. With.

  The rotary joint 1 is configured, for example, as a connection portion that liquid-tightly connects a fixed path and a rotation path in the liquid filling system, and the fixed shaft 10 is liquid-tightly connected to a liquid supply source (not shown) via a supply pipe. Connected. The rotary shaft 20 is liquid-tightly connected to a liquid filling device (not shown).

  The liquid filling device includes, for example, a vertical rotation shaft that is rotatably supported by a support portion and is rotated by a motor, a hollow disc-shaped main body portion that is connected to an upper end on the axis of the vertical rotation shaft, A plurality of (for example, about 100) filling nozzles provided on the lower surface of the main body portion with the axis as the center are provided. A connection port connected to the rotary shaft 20 of the rotary joint 1 is formed on the upper surface of the main body.

In the rotary joint 1, one of the pair of seal rings 31 and 32 constituting the mechanical seal 30 is fixed to the fixed shaft 10, and the other is fixed to the rotary shaft 20, and they are pressed against each other by the biasing force of the spring. ing.
These seal rings 31 and 32 are made of ceramics that are generally used in the mechanical seal 30 of the rotary joint 1, and their opposing seal surfaces are smoothed to a predetermined surface roughness or less.

The fixed shaft 10 is made of a metal that is difficult to corrode (for example, stainless steel) and has an outer flange portion 10a.
A cylindrical mechanical case 11 is connected to the lower surface of the outer peripheral portion of the outer flange portion 10a of the fixed shaft 10 with a bolt. The mechanical case 11 covers the periphery of the mechanical seal 30.

  A fixed seal ring 31 is fixed to the lower end surface of the fixed shaft 10 between the mechanical case 11 and the mechanical seal 30 via a cylindrical bellows member 12 that can be elastically deformed in the axial direction. The holder 13 for fixing the rotary seal ring 32 and the rotary seal ring 32 to the upper end surface of the rotary shaft 20 are provided.

  The bearing 40 is an open-type radial ball bearing (deep groove ball bearing), an inner ring thereof is fixed to the outer peripheral surface of the rotary shaft 20, and an outer ring thereof is fixed to the inner peripheral surface of the housing 50. In the case of the first embodiment, a pair of upper and lower bearings 40 are provided in the bearing chamber 50 a between the rotary shaft 20 and the housing 50 with a predetermined interval. In the present invention, the type of the bearing is not limited to the deep groove ball bearing because the type of the bearing needs to be periodically supplied with grease.

  The housing 50 is connected to the lower end portion of the mechanical case 11 with a bolt. The housing 50 includes a cylindrical portion 51 that contacts each outer ring of the pair of upper and lower bearings 40, an annular first spacer 52 disposed on the upper bearing 40 so as to constitute an upper wall of the bearing chamber 50a, a bearing An annular second spacer 53 disposed under the lower bearing 40 so as to constitute a lower wall of the chamber 50 a and an annular third spacer 54 provided under the second spacer 53 are provided.

The inner circumferential surface and the outer circumferential surface of the first spacer 52 are formed with a concave circumferential groove for fitting a sealing material. The concave circumferential groove on the inner circumferential surface side is provided with a slipper seal 55, and the outer circumferential surface side. An O-ring 56 is provided in the concave circumferential groove.
In addition, concave grooves for fitting the seal material are formed on the inner peripheral surface and the outer peripheral surface of the second spacer 53, and a slipper seal 57 is provided in the concave peripheral groove on the inner peripheral surface side. An O-ring 58 is provided in the concave groove on the surface side.

With these sealing materials, the bearing chamber 50a in which the pair of upper and lower bearings 40 are accommodated is sealed liquid-tight from the outside. The slipper seals 55 and 57 that are in sliding contact with the outer peripheral surface of the rotating rotary shaft 20 are integrally provided with a fluororesin (PTFE) ring portion on the sliding contact side and an elastomer ring on the non-sliding contact side. Sealing material with excellent wear resistance and durability.
A concave circumferential groove for fitting a sealing material is also formed on the inner circumferential surface of the third spacer 54, and a slipper seal 59 is provided in the concave circumferential groove.

The rotary shaft 20 is made of a metal that is not easily corroded (for example, stainless steel), and a holder 21 that is connected to the upper end of the rotary shaft 20 by a bolt and holds the seal ring 32 on the rotating side is provided. A flange 22 is provided on the outer peripheral surface of the lower end of the first and second flanges so as to be integrally rotatable. The flange 22 is connected by an upper surface bolt of the main body portion of the liquid filling device, whereby the lower end opening of the rotary shaft 20 is liquid-tightly connected to the connection port of the main body portion.
Further, a sleeve member 60 is fixed in a liquid-tight manner to the outer peripheral surface of the rotary shaft 20, and the slipper seal 59 is in sliding contact with the outer peripheral surface of the sleeve member 60.

  The cylindrical portion 51 of the housing 50 is formed with a plurality of upper and lower screw holes 51a communicating with the bearing chamber 50a. Usually, each screw hole 51a has a plug 71 having a male screw portion (FIG. 2A). Are screwed and plugged. A hexagonal recess into which a hexagon wrench is fitted is provided on one end surface of the plug 71.

In the case of the first embodiment, four screws 51 a are provided in the upper, middle, and lower stages in the circumferential direction at intervals of central angles of 90 ° around the axis P of the cylindrical portion 51.
The upper four screw holes 51a communicate with the upper space of the upper bearing 40 in the bearing chamber 50a.
The four middle screw holes 51a communicate with an intermediate space between the upper and lower bearings 40 in the bearing chamber 50a.
The lower four screw holes 51 a communicate with the space between the second spacer 53 and the third spacer 54.
The number of screw holes 51a in each step is not limited to four, and may be two, three, five, six, etc. at equal intervals in the circumferential direction.

<How to prevent bearing condensation>
FIG. 5 is a conceptual diagram illustrating a bearing dew condensation prevention method for a rotary joint according to the present invention.
It is necessary to fill the bearing chamber 50a of the rotary joint 1 assembled at the time of manufacture or maintenance with grease.

When filling the grease, a grease gun G shown in FIG. 4, a compressor C and a dryer D shown in FIG. 5 are prepared.
Grease gun G includes a nozzle G _11, a body portion G1 having a handle G ₁₂ and trigger G _13, and a grease housing case G2 removably mounted between the nozzle G ₁₁ and the trigger G ₁₃ of the main body G1 In use, grease is stored in the grease storage case. In addition, when rotary joint 1 is used for filling and packaging of food and drink, it is preferable to use grease for food machinery as grease, for example, white bear grease manufactured by JX Nippon Mining & Energy Corporation can be used.

In grease gun G, the nozzle G ₁₁ has a discharge port for pressed against and fitted to the tip of the grease nipple 72 shown in FIG. 2 (B), the handle G ₁₂ is shown in FIG. 2 (4) at its lower end A male coupler 74 is attached.

  In the case of the first embodiment, first, among the four screw holes 51a of each stage of the rotary joint 1, one screw hole 51a is used as a grease filling port, and the remaining three screw holes 51a are used as discharge ports. use. Therefore, at each stage, the grease nipple 72 (FIG. 2B) is attached to one screw hole 51a, and the relief nipple 73 (FIG. 2C) is attached to the remaining three screw holes 51a. For each screw hole 51a in the lower stage, a grease nipple 72 with a check valve and a relief nipple 73 are mounted after a grease leakage test described later.

  The grease nipple 72 has a ball and a spring inside. The ball closes the tip opening 72a by the biasing force of the spring, and the ball is pushed by the external pressure exceeding the biasing force of the spring, so that the tip opening 72a. Is configured to open.

  The relief nipple 73 has a cylindrical main body portion 73a and a shaft portion 73b inserted into the center hole of the main body portion 73a. When a pressure higher than a predetermined pressure is applied to the shaft portion 73b, the shaft portion 73b is outward. It is comprised so that it may move to and a clearance gap may be formed between the main-body parts 73a.

  Next, in order to fill the grease nipple 72 of each stage with the grease, the compressor C and the dryer D are connected by the first pressure hose H1, and the dryer D and the grease gun G are indicated by a two-point chain plug. Connect with 2 hose H2. In addition, the male coupler 74 of the grease gun G and the female coupler 75 (FIG. 3) which can be attached or detached are attached to the front-end | tip part of the 2nd hose H2.

  Thereafter, the compressor C and the dryer D are driven, and compressed air is supplied from the compressor C to the dryer D. At this time, the air is compressed at a predetermined pressure by the compressor C, so that the amount of water vapor exceeding the amount of saturated water vapor corresponding to the pressure and temperature of the compressed air becomes water droplets and accumulates in the compressor C. The water accumulated in the compressor C is periodically drained.

  The compressed air supplied from the compressor C to the dryer D has some moisture removed as described above, but in the present invention, moisture is further removed by the dryer D to generate dry air. At this time, the humidity of the dry air is preferably 15% or less, more preferably 11% or less, and particularly preferably 8% or less when the humidity is 10 to 35 ° C. and atmospheric pressure.

  After the grease gun G supplied with compressed dry air from which moisture has been further removed as described above is blown several times to confirm that grease is discharged from the nozzle G11, the nozzle G11 is pressed against the upper grease nipple 72. Then, the trigger G13 is pulled to fill the upper space of the bearing chamber 50a with grease by the pushing force of the compressed dry air. Then, the grease is sequentially discharged from the three relief nipples 73, and the relief nipple 73 from which the grease has been discharged is removed and replaced with the plug 71.

When the grease is discharged from the last relief nipple 73 in the upper stage, the filling of the grease is stopped, the last relief nipple 73 is replaced with the plug 71, and the grease nipple 72 is replaced with the plug 71.
Next, the intermediate space in the bearing chamber 50a is filled with grease in the same manner as the grease filling operation in the upper space, and the plug 71 is replaced with each screw hole 51a in the middle stage to seal the bearing chamber 50a.

Thereafter, a fiberscope is inserted from each screw hole 51a in the lower stage, and an inspection is performed as to whether grease has leaked into the space between the second spacer 53 and the third spacer 54. Thereby, the soundness of the slipper seal 57 is confirmed.
After the inspection, the grease nipple 72 and the relief nipple 73 are attached to the lower screw holes 51a, and the space between the second spacer 53 and the third spacer 54 is filled with grease in the same manner as described above. A plug 71 is attached to the.

  According to the bearing dew condensation prevention method of the rotary joint of the first embodiment, the amount of moisture in the bearing chamber 50a is significantly larger than when the grease is filled in the bearing chamber 50a with compressed air from which moisture has not been sufficiently removed. It is possible to prevent the occurrence of condensation within the bearing chamber 50a and the occurrence of bearing rust due to condensation. In addition, the viscosity of the grease in the bearing chamber 50a is reduced due to condensation, and leakage of the reduced viscosity of grease from the bearing chamber 50a can be prevented.

(Embodiment 2)
In the method for preventing bearing dew condensation of the rotary joint according to the second embodiment, before the bearing chamber 50a is filled with grease, the air in the bearing chamber 50a is replaced with dry air to dry the bearing chamber 50a. This is the same as the first embodiment.
In this case, replacement of dry air is performed on the upper and lower spaces in the bearing chamber 50 a and the space between the second spacer 53 and the third spacer 54. An example will be described below.

  First, when replacing the dry air, the male coupler 74 (FIG. 2D) is attached to one screw hole 51a in each stage. Next, the female coupler 75 of the second hose H2 of the dryer D connected to the compressor C shown in FIG. 5 is combined with the upper male coupler 74, and compressed dry air is sent into the upper space in the bearing chamber 50a. Replace existing air in the upper space with dry air. At this time, by supplying the compressed dry air continuously for a predetermined time (for example, 30 seconds) or longer, it can be considered that the existing air in the upper space is almost completely replaced with the dry air.

  The existing air in the lower space of the bearing chamber 50a and the existing air in the space between the second spacer 53 and the third spacer 54 are also replaced with dry air in the same manner as described above.

  Before stopping the supply of compressed dry air at each stage, the relief nipple 73 is attached to the two screw holes 51a, and then the supply of the compressed dry air is stopped by removing the female coupler 75 from the male coupler 74. Good. In this way, after stopping the supply of compressed dry air, it is possible to suppress the outside air from being mixed into the dry air in the bearing chamber 50a, and to shorten the time until the start of the next grease filling process. it can.

  According to the bearing dew condensation prevention method of the rotary joint of the second embodiment, since the inside of the bearing chamber 50a can be dried in advance with dry air, the moisture content in the bearing chamber 50a that is filled with grease and then sealed with dry air after that. Can be further reduced. As a result, it is possible to enhance the effect of preventing the occurrence of condensation, the occurrence of bearing rust due to condensation, and the leakage of grease from the bearing chamber 50a due to condensation.

(Embodiment 3)
In the first and second embodiments, a sterilization function may be added to the dryer D, and the sterilized compressed dry air may be introduced into the bearing chamber 50a. At this time, for example, a sterilization dryer manufactured by Fukuhara Co., Ltd. (type: D22A-MG-1) having a sterilization performance of 99.99999% or higher (LRV value ≧ 7) is used.
In this way, since the growth of bacteria in the bearing chamber 50a can be effectively suppressed, the inside of the bearing chamber 50a can be kept hygienic. In particular, a bearing suitable for a rotary joint for foods can be used. Condensation prevention and sterilization can be performed.

(Other embodiments)
In the first to third embodiments, a function of removing bacteria, oil, dust, fine particles, and the like is added to the dryer D, and compressed dry air from which moisture, bacteria, oil, dust, fine particles, and the like are removed is introduced into the bearing chamber 50a. You may do it.
In this way, the quality of the grease filled in the bearing chamber 50a can be improved and deterioration can be suppressed, leading to improvement in the performance and durability of the bearing 40, and sanitization by sanitizing the inside of the bearing chamber. Can be kept in.

  The disclosed embodiments should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Rotary joint 10 Fixed shaft 20 Rotary shaft 30 Mechanical seal 40 Bearing 50 Housing 50a Bearing chamber 51a Screw hole (filling port, discharge port)
55, 57, 59 Slipper seal 72 Grease nipple 73 Relief nipple G Grease gun P-axis

Claims (6)

A fixed shaft and a rotary shaft arranged coaxially, a mechanical seal that allows the fixed shaft and the rotary shaft to slide in a rotation direction about an axis, and a bearing attached to an outer peripheral surface of the rotary shaft; A rotary joint having a housing connected to the fixed shaft to form a bearing chamber for housing the bearing, the housing having a filling port and a discharge port communicating with the bearing chamber;
A bearing dew condensation prevention method for a rotary joint, characterized in that grease is filled in the bearing chamber by pushing force of compressed dry air, and then the bearing chamber is sealed.   The bearing condensation prevention method of a rotary joint according to claim 1, wherein air in the bearing chamber is replaced with dry air before the bearing chamber is filled with grease.   A grease nipple is attached to the filling port, and a relief nipple that opens when a predetermined pressure is exceeded is attached to the discharge port, and then grease is added to the filling port through the grease nipple together with compressed dry air using a grease gun. The bearing condensation prevention method of the rotary joint of Claim 1 or 2 with which it fills.   The bearing dew condensation prevention method of the rotary joint as described in any one of Claims 1-3 which provides a slipper seal in the contact part with the outer peripheral surface of the said rotary shaft in the said bearing chamber.   5. The method for preventing bearing condensation in a rotary joint according to claim 1, wherein the dry air has a relative humidity of 15% or less at a temperature of 10 to 35 ° C. and an atmospheric pressure.   The method according to claim 1, wherein the dry air has been sterilized.