JP5491873B2 - Gland packing - Google Patents

Description

  The present invention relates to a gland packing, and more particularly to a gland packing used for sealing a shaft portion of a rotary / reciprocating device such as a pump.

  Gland packing is used in locations that involve rotation or sliding movements such as valve stems, rotating shafts of fluid equipment or equipment, but in these locations energy loss due to operating resistance is accompanied, reducing operating resistance. It is indispensable to reduce the energy consumption of the power source and to extend the life of the packing.

  In recent years, the use of asbestos-based gland packing has been restricted in consideration of the impact on the natural environment. For example, gland packing for shaft sealing of agitator pumps in various chemical liquid lines in the paper industry that dislikes black As a substitute for asbestos (white asbestos), white non-asbestos gland packing is used.

  As described above, the white non-asbestos gland packing used in the paper industry etc. is based on organic fibers such as aramid fibers and PTFE fibers, or inorganic fibers such as glass fibers and ceramic fibers according to the required characteristics. In addition, metal particles, inorganic powder particles, PTFE dispersion, and the like are added to these base materials as auxiliary materials.

  By the way, in order to manufacture the gland packing, first, the above-described one or two or more kinds of organic fibers or inorganic fibers are knitted by lattice knitting, bag knitting, eight knitting, etc. By pressing, for example, a gland packing 10 having a square cross section as shown in FIGS. 4 and 5 is formed (Patent Document 1). The strand is formed from one fiber or a plurality of bundled fibers.

  Here, for example, the cross-sectional structure of the packing body 10A in the gland packing 10 manufactured industrially by a knitting machine that performs lattice knitting has a configuration as shown in FIG. That is, from the center core yarn 4 located at the center, the corner yarn 6 disposed on the outer square of the center core yarn 4, the center core yarn 4, the corner yarn 6, and the braided yarn 8 constituting the outer cover. It is configured.

JP 2001-192644 A

  By the way, in such a conventional white non-asbestos gland packing 10, all of the packing main body 10A is formed of the same fiber (yarn) -shaped yarn. That is, all of the core yarn 4, the square yarn 6, and the braided yarn 8 were either formed of filament yarn, or all of them were formed of spun yarn or blended yarn.

  However, if the entire packing body 10A is formed in a single fiber shape as described above, the overall hardness may be too high, or conversely, the hardness may be too low. It was difficult to provide suitable hardness.

If the hardness is too high, the handleability is poor and the mounting operation becomes difficult. For example, when mounting on a rotary device such as a pump, the peripheral surface of the sliding shaft may be damaged.
On the other hand, if the hardness is too low, additional tightening must be performed many times during use.

  In view of such a conventional situation, the present invention can adjust the hardness and flexibility as needed regardless of the gland packing used in any field. An object of the present invention is to provide a gland packing that can exhibit effective sealing performance for a long time without retightening.

The gland packing according to the present invention for achieving the above object is
A gland packing having a cross-sectional structure composed of an outer portion (A ₁ ) formed of braided filament yarn and a central portion (A ₂ ) surrounded by the outer portion (A ₁ ),
Entirety of the central portion (A ₂₎ is formed from spun yarns and / or a blended yarn that is not braided,
The braided filament yarn forming the outer portion (A ₁ ) and the unbraided spun yarn and / or blended yarn forming the central portion (A ₂ ) are made of PPS (polyphenylene sulfide resin) fibers,
Furthermore , the composition ratio of the outer portion (A ₁ ) and the central portion (A ₂ ) is a weight ratio (“weight of spun yarn and / or blended yarn forming the central portion (A ₂ )” / “outer portion (A ₁ ) The weight of the filament yarn forming ""), and is characterized by being in the range of 3/7 to 1/9 .

With the gland packing having such a configuration, the outer portion (A ₁ ) that contacts the rotating shaft or the like is formed of a braided filament yarn so as to give a predetermined hardness. The fibers are not damaged even by resistance, and a long-term stable sealing property can be realized. In addition, since a spun yarn or a mixed spun yarn having higher flexibility than the filament yarn is also used in the central portion (A ₂ ), desired flexibility can be obtained as a whole gland packing, and the rotation shaft and the like can be obtained. Familiarity and high sealing performance can be realized.

If the braided filament yarn forming the outer portion (A ₁ ) and the unbraided spun yarn and / or blended yarn forming the central portion (A ₂ ) are formed of PPS fibers, PPS fibers Is flame retardant, has excellent heat resistance and chemical resistance, and has wear resistance and dimensional stability at high temperatures, so it supplies chemicals as a sealing material to replace asbestos. It can be used effectively for lines and the like.

Furthermore, if the entire central portion (A ₂ ) is formed from spun yarn and / or blended yarn that is not braided, higher flexibility is obtained as the entire gland packing, and the familiarity with the rotating shaft and the like is good. High sealing performance can be realized. Moreover, since the spun yarn and the blended yarn are less expensive than the filament yarn, the material cost for manufacturing the gland packing can be reduced.
Further, by appropriately adjusting the composition ratio between the outer portion A ₁ formed of the braided filament yarn and the central portion A ₂ formed of the unknitted spun yarn and / or the blended yarn, an appropriate hardness can be obtained. And desired flexibility.

According to the gland packing according to the present invention, the outer portion (A ₁ ) of the cross section of the gland packing is formed of braided filament yarn, and the central portion (A ₂ ) surrounded by the outer portion (A ₁ ). Since spun yarns and blended yarns that are more flexible than filament yarns are also used, appropriate hardness and desired flexibility can be obtained as a whole gland packing, and it can be used with a rotating shaft for a long time. Highly stable sealing performance can be realized.

  Thereby, the handleability is good and the sliding surface of the fluid device is not damaged when the gland packing is attached. In addition, the number of retightenings can be reduced in order to obtain a stable sealing property, and an effective sealing property can be exhibited over a long period of time.

  Furthermore, if the packing body is formed of PPS fibers, it exhibits chemical resistance that is comparable to that of fluororesin, and has excellent physical properties such as heat resistance. It is possible to exhibit effective sealing performance over a wide range.

FIG. 1 is a cross-sectional view showing a staffin box to which a gland packing of the present invention is attached. FIG. 2A is a cross-sectional view illustrating a schematic configuration of the gland packing employed in FIG. 1. FIG. 2B is a cross-sectional view showing components of the gland packing of FIG. 2A. FIG. 3A is a perspective view showing a gland packing formed by eight stitches. FIG. 3B is a perspective view showing a gland packing formed by lattice knitting. FIG. 3C is a perspective view showing a gland packing formed by bag knitting. FIG. 4 is a perspective view showing a conventional gland packing formed by lattice knitting in a partially loosened state. FIG. 5 is a cross-sectional view showing components of the conventional gland packing shown in FIG. FIG. 6 is a schematic sectional view showing an experimental apparatus for examining the characteristics of the gland packing according to the present invention. FIG. 7A is experimental data showing the transition of the leakage amount of the gland packing manufactured according to the present invention. FIG. 7B is experimental data showing the temperature change in the staffin box equipped with the gland packing manufactured according to the present invention. FIG. 7C is experimental data showing the transition of the axial resistance of the gland packing manufactured according to the present invention. FIG. 7D shows experimental data obtained by examining the change in the mounting length when four gland packings manufactured according to the present invention are mounted side by side. FIG. 8A is experimental data showing the transition of the leakage amount of the gland packing of Comparative Example 1. FIG. 8B is experimental data showing a temperature change in the staffin box equipped with the gland packing of Comparative Example 1. FIG. 8C is experimental data showing transition of axial resistance of the gland packing of Comparative Example 1. FIG. 8D is experimental data obtained by examining a change in the mounting length when four gland packings of Comparative Example 1 are mounted side by side. FIG. 9A is experimental data showing the transition of the leakage amount of the gland packing of Comparative Example 2. FIG. 9B is experimental data showing a temperature change in the staffin box to which the gland packing of Comparative Example 2 is attached. FIG. 9C is experimental data showing changes in axial resistance of the gland packing of Comparative Example 2. FIG. 9D is experimental data obtained by examining a change in the mounting length when four gland packings of Comparative Example 2 are mounted side by side.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a stuffing box fitted with the gland packing of the present embodiment. On the peripheral surface of the stem 2 in the stuffing box 1, an annular gland packing 3a is disposed in contact with the bottom 4 of the staffin box 1, and the other three gland packings 3b, 3c, and 3d are also provided. It is installed in series. Since the gland packings 3a, 3b, 3c, and 3d all have the same structure, all of them may be referred to as the gland packing 3 in the following description.

  All the strands constituting the gland packing 3 of this embodiment are made of PPS (polyphenylene sulfide) fibers. PPS fibers are rich in flame retardancy, heat resistance, and chemical resistance, and further have wear resistance and excellent dimensional stability at high temperatures. The gland packing 3 is formed by braiding a part or the whole of the yarn composed of PPS fibers by an appropriate braiding method, in this embodiment, by lattice braiding, pressing, and cutting.

As shown in FIG. 2A, the cross-sectional structure of the gland packing 3 of this embodiment is composed of a central portion A ₂ and an outer portion A ₁ that surrounds the center portion A ₂ . Further, as shown in FIG. 2B, the outer portion A ₁ is formed from the jacket braided yarn 50, and the central portion A ₂ is formed from the core yarn 20, the square yarn 30, and the opposite side yarn 40. ing.

Moreover, in the gland packing 3 of the present embodiment, the outer portion A ₁ is formed of a braided filament yarn. That is, the jacket braided yarn 50 that forms the outer portion A ₁ is a filament yarn and is braided. Since the braided filament yarn has a high hardness, the hardness of the entire gland packing 3 can be increased by increasing the constituent ratio of the outer portion A _{1 in} the entire gland packing 3.

Further, in the gland packing 3 of the present embodiment, the entire central portion A ₂ is formed by spun yarns and / or a blended yarn that has not been braided. Such spun yarn and blended yarn have higher flexibility than filament yarn. Furthermore, since it is not braided, it is more flexible. Therefore, the flexibility of the whole gland packing 3 can be increased by increasing the proportion of the central portion A _{2 in} the whole gland packing 3.

That is, the gland packing 3 according to the present invention has a composition ratio between the outer portion A ₁ formed of the braided filament yarn and the central portion A ₂ formed of the unknitted spun yarn and / or the blended yarn. By adjusting as appropriate, appropriate hardness and desired flexibility can be provided. The preferred composition ratio of the outer portion A ₁ and the central portion A ₂ varies depending on the size of the gland packing, but the weight ratio (“weight of spun yarn and / or blended yarn forming the central portion A ₂ ” / “ in the outer part by weight of the filament yarn forming the a ₁ "), it is generally in the range of 3 / 7-1 / 9.

In the gland packing 3 of the present embodiment, as described above, the entire central portion A ₂ is formed by spun yarns and / or blended yarns, the present invention is not limited thereto. That is, in the gland packing 3 according to the present invention, it is only necessary that at least a part of the central portion A ₂ is formed of spun yarn and / or blended yarn. For example, referring to FIG. 2B, only the middle core yarn 20 of the middle core yarn 20, the square yarn 30 and the opposite side yarn 40 is formed of a spun yarn and / or a blended yarn, and the square yarn 30 and the opposite side yarn are formed. 40 may be formed of filament yarn. Further, for example, only a part of the core yarn 20 can be formed by spun yarn and / or blended yarn, and the other portions can be all formed by filament yarn.

Further, in the gland packing 3 of the present embodiment, as described above, the entire central portion A ₂ is not braided, but in the present invention, a part or the entire central portion A ₂ may be braided.

Thus, the gland packing 3 according to the present invention may be the filament yarn is used for a portion of the central portion A _2, a portion or all of the central portion A ₂ may be braided. However, in order to obtain a higher flexibility as a whole gland packing and to reduce the material cost for the production of the gland packing, the entire central part (A ₂ ) may be made of unwoven braided yarn and / or It is preferably formed from blended yarn.

  In this embodiment, all the yarns forming the gland packing 3 are formed of PPS fibers, but the yarns forming the gland packing 3 of the present invention are not limited to PPS fibers. Therefore, for example, any one of organic fibers such as aramid fibers, polyester fibers, and synthetic fibers, inorganic fibers such as carbon fibers, glass fibers, and rock wool, or a plurality of the above-described fibers can be employed.

However, it is preferable to use a filament yarn made of PPS fiber for at least the outer portion A ₁ in contact with an external fluid, and to suitably use the gland packing 3 according to the present invention in a line through which various chemicals such as acid and alkali flow. This is preferable.

Further, the gland packing 3 of the present embodiment, as shown in FIG. 2B, but the outer portion A ₁ is formed from a jacket braided yarns 50 of first layer, the outer portion A ₁ of the present invention to It is not limited and may be formed from a plurality of layers.

  Further, as described above, the gland packing 3 of this embodiment is braided by lattice knitting, but the gland packing 3 according to the present invention may be manufactured by any braiding method. For example, it may be braided by a braiding method such as eight knitting as shown in FIG. 3A, lattice knitting as shown in FIG. 3B, or bag knitting as shown in FIG. 3C.

  In the present invention, for example, as disclosed in Japanese Patent Application Laid-Open No. 2004-169823, if the surface or inside of the gland packing base material is impregnated with water-swellable mica, baking is prevented and an excellent seal is obtained. Sex can be maintained.

Although the gland packing of the present invention has been described above, the present invention is not limited to the above-described embodiment.
For example, a material added as an auxiliary material to a base material made of PPS fibers is not limited to water-swellable mica, and known materials such as lubricating oil and PTFE dispersion can be appropriately used according to required characteristics. Since the auxiliary material added to these base materials is not the gist of the present invention, the details are omitted.

Below, the comparative test performed in order to confirm the characteristic of the gland packing which concerns on this invention is demonstrated.
The gland packing used as a test sample was manufactured by lattice knitting both in the case of Example 1 which is a product of the present invention and in the case of Comparative Examples 1 and 2 which are conventional examples.

First, all the gland packings of Example 1 which are invention products are formed from PPS fibers. Then, as shown in FIGS. 2A and 2B, the envelope braided yarn 50 which constitute the outer portion A ₁ of the first embodiment is made filament yarns are formed braided filament yarn once. Also, the central core 20 and Kakuito 30 and opposite side yarn 40 constituting the central portion A ₂ of the first embodiment, is formed from all the spun yarn, not and braided.

On the other hand, in the gland packing of Comparative Example 1, all of the outer portion A ₁ and the central portion A ₂ shown in FIG. 2A are made of spun yarn of PPS. Only the jacket braided yarn 50 of the outer portion A ₁ is braided, and the center core 20, the square yarn 30, and the opposite side yarn 40 constituting the central portion A ₂ are not braided.

Further, in the gland packing of Comparative Example 2, the outer portion A ₁ and the central portion A ₂ are all made of filament yarns of PPS fibers. In Comparative Example 2, including the outer cover braided yarn 50, a central core 20 which constitutes the central portion A _2, and angle yarns 30, the opposite side yarn 40, not all of braiding.

Table 1 shows the gland packing used in the above-described Examples, Comparative Examples 1 and 2, and the types of fibers, the shape of the yarn, and the presence or absence of braiding in the outer portion A ₁ and the inner portion A ₂ . As shown in

In Table 1, the outer portion A ₁ and the central portion A ₂ are simply indicated as A ₁ and A ₂ , respectively. Further, when the outer portion A ₁ (or the central portion A ₂ ) is braided, it is indicated by “◯”, and when it is not braided, it is indicated by “x”.

Outline of Test Apparatus FIG. 6 shows a horizontal rotation test apparatus used for examining the characteristics of the gland packing. In this test apparatus, the main shaft is inserted through the packing box in the horizontal direction. And gland packing 3a, 3b, 3c, 3d is accommodated between the shaft sleeve mounted on the outer peripheral side of the main shaft and the outer packing box, and these gland packings 3a, 3b, 3c, 3d are It is pressed by the packing presser. As these gland packings 3a, 3b, 3c, and 3d, the gland packing of any one of Example 1 or Comparative Examples 1 and 2 was mounted and a test was performed.

The packing box is provided with temperature measuring means such as a thermometer, and the temperature measuring means detects the temperature of the fluid (tap water) and the temperature in the packing box.
In this test apparatus, the main shaft is rotated by a motor, and tap water which is a pressure fluid is introduced from above. Then, tap water leaked outward from the gap of the packing presser was received by a measuring cylinder, and the leaked capacity was measured. Further, the temperature in the packing box was particularly detected by the temperature measuring means.
Further, during continuous operation, changes in axial resistance against the rotation of the main shaft and the total length of the packing were measured.

(1) Test conditions (Example 1 and Comparative Examples 1 and 2 have the same conditions)
Arrangement: 4 rings on one side (see Fig. 4)
Dimensions: φ80 × φ105 × 12.5 ^H
Rotational speed: 1194 rpm (circumferential speed 5 m / s) to 2388 rpm (circumferential speed 10 m / s)
Pressure: 0.49 MPa
Fluid: Tap water (about 40 ° C)

(2) Test jig test sample size: φ80 × φ105 × 12.5 ^H (Up to 7 rings on one side can be mounted)
Peripheral speed (number of rotations): max 15 m / s (3582 rpm)
Indentation pressure: max 10kgf / cm

(3) Measurement items [1] Amount of leakage (cc / min)
[2] Packing box temperature (° C)
[3] Axial resistance (N · m)
[4] Packing installation length (measured to 0.01 mm)

(4) Test procedure [1] Install the packing in the packing box.
[2] Measure the packing mounting length before tightening.
[3] Tighten the packing retainer bolt and apply a water pressure of 0.49 MPa.
[4] When the amount of leakage is large (200 cc / min or more), the nut is tightened by 1/6 to 1/12 turn with a spanner to adjust the leakage amount (100 cc / min or less).
[5] -1. When rotating at 1194 rpm (circumferential speed 5 m / s) and the amount of leakage is large (200 cc / min or more), the nut is tightened by 1/6 to 1/12 turn with a spanner to adjust the amount of leakage.
[5] -2. Perform a continuous operation for 60 hours or more and perform a predetermined measurement.
[5] -3. After continuous operation for 60 hours or more at 1194 rpm (circumferential speed 5 m / s), if the rotation is continuously increased to 2388 rpm (circumferential speed 10 m / s) and the amount of leakage increases, 1/6 nuts with a spanner Tighten by 1/12 rotations to adjust the amount of leakage (100cc / min or less).
[6] Perform a continuous operation for 200 hours or more and perform a predetermined measurement.

(5) Test Results FIGS. 7A, 7B, 7C and 7D show the test results of the gland packing according to Example 1 which is a product of the present invention.
8A, 8B, 8C, and 8D show the test results of the gland packing according to Comparative Example 1. FIG.
9A, 9B, 9C, and 9D show the test results of the gland packing according to Comparative Example 2. FIG.

  7B, 8B, and 9B show the results of examining the temperature in the packing box with respect to the measurement time, and FIGS. 7C, 8C, and 9C show the results of examining the axial resistance with respect to the measurement time. 7D, FIG. 8D, and FIG. 9D have shown the result of having investigated the change of the 4 length (ring) gland packing mounting length with respect to measurement time.

The result of the leak :
As shown in FIG. 7A, the gland packing of Example 1 has no significant difference in the leakage amount between the motor side gland packing and the non-motor side gland packing. It was confirmed that the sealability was good.

  On the other hand, in Comparative Example 1, since the amount of leakage was large at the initial stage of operation, it was necessary to adjust the tightening pressure. Further, in Comparative Example 2, since the seizure occurred on the motor side immediately after the start of operation, it was necessary to reduce the rotational speed to 5 m / s or less and then increase it again to 5 m / s. After tightening one and a half hours after the start of operation, it was confirmed that seizure occurred on the non-motor side. Further, there was a seizure phenomenon on the non-motor side even 24 hours after the start of operation. The occurrence of baking was confirmed visually.

Result of temperature change :
In Example 1, as shown in FIG. 7B, the temperature inside the packing box has a substantially constant difference between the non-motor side and the motor side, and the temperature is substantially constant until the operation time is close to 120 hours. There was no significant increase or decrease. Thereby, it was confirmed that there was temperature safety. In the case of Comparative Example 1, the temperature was higher than that of Example 1 as a whole, and a temperature increase was particularly observed in the initial stage of operation.
In Comparative Example 2, the variation in temperature was large from the beginning of operation to around 80 hours. In particular, on the motor side, it was confirmed that the temperature rose to around 60 ° C.

Axial resistance results :
In the case of Example 1, a stable value was shown relatively quickly after the operation was started. When tightening was performed around 120 hours from the start of operation, although a slight increase was observed, there was no significant change thereafter. During the subsequent tightening, no temperature change was observed. In the case of Comparative Example 1, since there were many leaks after the start of operation, it was necessary to perform additional tightening, so the axial resistance at the beginning of the operation was high. In the case of Comparative Example 2, the axial resistance was high from the beginning of the operation, and then gradually decreased.

Installation length results :
In the case of Example 1, it was performed approximately every 100 hours of additional tightening from the start of operation, but the change in the mounting length after additional tightening was small. In Comparative Example 1, since there are many leaks immediately after the start of operation (200 cc / min or more), it is necessary to perform additional tightening within a short time from the start of operation, and the length of the mounting length decreases each time. . In the case of Comparative Example 2, since the seizure occurred on the motor side immediately after the start of operation, it was necessary to lower the rotational speed to 5 m / s or less and then increase it again to 5 m / s. At the same time, it was necessary to loosen the tightening. there were.

  As can be seen from the above test results, it was confirmed that the gland packing according to the present invention has a suitable hardness and a suitable flexibility as compared with Comparative Examples 1 and 2, and has little leakage.

1 Staffin box 3, 3a, 3b, 3c, 3d Gland packing 20 Center core 30 Square thread 40 Opposite thread 50 Outer braided thread A Packing body A ₁ Outer part A ₂ Central part

Claims (1)

A gland packing having a cross-sectional structure composed of an outer portion (A ₁ ) formed of braided filament yarn and a central portion (A ₂ ) surrounded by the outer portion (A ₁ ),
Entirety of the central portion (A ₂₎ is formed from spun yarns and / or a blended yarn that is not braided,
The braided filament yarn forming the outer portion (A ₁ ) and the unbraided spun yarn and / or blended yarn forming the central portion (A ₂ ) are made of PPS (polyphenylene sulfide resin) fibers,
Furthermore , the composition ratio of the outer portion (A ₁ ) and the central portion (A ₂ ) is a weight ratio (“weight of spun yarn and / or blended yarn forming the central portion (A ₂ )” / “outer portion (A ₁ ) Gland packing characterized in that it is in the range of 3/7 to 1/9 " .

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