BG4497U1 - Diagonally braided packing - Google Patents

Abstract

The diagonally braided packing is used in mechanical engineering, particularly for sealing the packing chambers of pumps and valves used in the chemical, pharmaceutical, petroleum and other industries. It provides a larger contact surface between the various rings and the face of the gland cover, which converts the axial force F into a radial force P evenly distributed over the outer surface of the sealed shaft and the inner surface of the gland box. The diagonally braided packing has a trapezoidal cross section of rectangular trapezoid shape. The packing comprises a first filling (1.1) having a maximum number of filaments, and a second filling (1.2), a third filling (1.3) and a fourth filling (1.4) having a decreasing number of filaments which are percentages of the number of filaments of the first filling (1.1). Around every second (1.2), third (1.3) and fourth (1.4) filling there is a braided yarn (2).

Description

The utility model relates to a diagonally braided packing which finds application in mechanical engineering, in particular, for sealing packing chambers of pumps and fittings which operate in installations in the chemical, pharmaceutical, petroleum and other industries.

Prior art

A number of diagonally braided packings are known, applied to the sealing of pumps and fittings, mounted on the sealing shaft, located in the stuffing box, which are made of different types of materials. The materials are technical yarns with small text that are inserted to the required text before being fed into the diagonal braiding machines. The packings produced by these machines have a square cross-section, fill the stuffing box, and have flexibility and ductility. Diagonal braiding machines provide such a movement of the shuttles that they follow a precisely defined trajectory and circle around the stuffing, thus ensuring the square structure of the stuffing and its flexibility when winding around the shaft in the stuffing box.

A disadvantage of the known packings is that when making the rings from the diagonally braided packing, the square section of the packings becomes trapezoidal, since the inner length of the circumference of the ring is less than the outer length of the circumference of the ring. The natural state of the rings when installed before the stuffing box is tightened into the stuffing box is a trapezoidal cross-section with the small base facing the inner surface of the stuffing box. By tightening the gland cover, the rings contact each other initially with the large base of the trapezoid that contacts the shaft and from this follows the greater force P, which acts on the outer surface of the shaft and leads to uneven and rapid wear of the packing and the shaft.

The closest in its technical nature to the diagonally braided stuffing, according to the useful model [1], is made up of multiple fillings with different numbers of threads inserted into a carrier yarn. The packing has a trapezoidal cross-section, the large outer upper base is intended for contact with the inner surface of the stuffing box and the small inner lower base is intended for contact with the shaft being sealed. The fillings with different numbers of threads are located asymmetrically along the cross-section of the packing, with the fillings with the highest number of threads located at the top of the trapezoidal cross-section and the fillings with the lowest number of threads located at the bottom of the trapezoidal section, before making rings from the stuffing it has a regular trapezoidal cross-section. Fillings with different numbers of threads are arranged symmetrically with respect to the vertical passed through the centers of the bases of the cross-section of the packing. The number of threads in the stuffing fillings decreases from the large trapezoidal base to the small trapezoidal base. The fillings with the highest number of threads are located at the top of the trapezoidal cross-section, and the fillings with the lowest number of threads are located at the bottom of the trapezoidal section.

A disadvantage of the known diagonally braided packing is that when the rings are prepared from it and before their installation in the stuffing box, the contact surface between the rings is limited only in the area of the large base of the trapezoid of their section. Thus, the transmission of the axial force F is difficult, and it is transmitted unevenly to the inner surface of the stuffing box and the outer surface of the shaft being sealed.

Another disadvantage of the known diagonally braided packing is that the face of the packing cover, which must transmit the axial force F, contacts the first ring produced by the packing only in a narrow contact strip, which is in the area of the large base of the trapezoid of the section.

Another disadvantage of the known diagonally braided packing is that when the stuffing box is tightened, the axial force F, transforming into a radial force P, creates a greater frictional force on the inner surface of the stuffing box and less force on the outer surface of the seals shaft which can cause shaft sealing problems. This is more pronounced when the selected packing size is used to seal shafts with diameters at the upper limit of the permissible shaft diameters for the given packing size.

Technical nature of the utility model

The task of the useful model is to create a diagonally braided packing, which, when making sealing rings from it, provides a shape of their cross-section that is as close as possible to the square one, as well as without changing the construction of the stuffing box, the method of installation or any other technical modification by the user of the packings, to provide a larger contact surface between the various rings and the stuffing box face, and which transforms the axial force F into a radial force P that is distributed uniformly to the outer surface to the shaft being sealed and to the inner surface of the stuffing box.

This task is solved by diagonally braided stuffing, made up of multiple fillings with different numbers of threads inserted into a carrier yarn. The packing has a trapezoidal cross-section, the large outer upper base is intended for contact with the inner surface of the stuffing box and the small inner lower base is intended for contact with the shaft being sealed. The fillings with different numbers of threads are located asymmetrically along the cross-section of the packing, with the fillings with the highest number of threads located at the top of the trapezoidal cross-section and the fillings with the lowest number of threads located at the bottom of the trapezoidal section. According to the utility model, the trapezoidal cross-section of the diagonally braided packing is in the shape of a right-angled trapezium having a large diagonal and a small diagonal. The large diagonal begins at the end of the upper outer base, where the acute angle between it and the inclined side of the trapezoid is formed, and ends at the end of the small lower inner base, where the lower right angle is formed between it and the vertical side. The small diagonal begins at the end of the large upper outer base, where the upper right angle formed between it and the vertical side is located, and ends at the end of the small lower inner base in the region of the obtuse angle. A section of a right trapezoid includes a right isosceles triangle whose right angle coincides with the upper right angle, its legs are parts of the large upper outer base and the vertical side, and its hypotenuse is the row of fills that is parallel to and precedes the large diagonal. All fillings in said isosceles right triangle are the same and are executed as the first fillings that have the maximum number of threads. At the intersection of the large diagonal of the rectangular trapezoid with its small diagonal, a third filling is located, which consists of 35% to 50% of the number of threads involved in the first filling. On both sides of the third filling, in the large diagonal, one second filling is located and after each of the second fillings, in the direction of the two ends of the large diagonal, at least one first filling is located. The second filling consists of 60% to 80% of the number of threads involved in the first filling. The fillings located next to the slanted side in the direction from the large upper outer base to the small lower inner base are fillings of decreasing thread count. In the region of the obtuse corner next to the small inner bottom base, a fourth filling is located, which has a minimum thread count and consists of 5% to 15% of the thread count of the first filling. Each of the next large diagonal rows of fillings located on the side of the obtuse angle, at its end next to the inclined side, contains a filling with a higher number of threads than the filling located at its end, located next to the lower inner base.

It is recommended that the number of threads of the first filling is 80.

It is recommended that the number of threads of the second filling is 70% to 75% of the number of threads of the first filling.

It is recommended that the thread count of the third filling be 40% to 50% of the thread count of the first filling.

It is recommended that the thread count of the fourth minimum fill be 7% to 10% of the thread count of the first fill.

The advantage of the diagonally braided packing, according to the useful model, is that when making sealing rings from it, it provides a shape of their cross-section that is as close as possible to the square one, as well as that without changing the construction of the stuffing box, nor the way of installation or any other technical change by the user of the packings, a larger contact surface is provided between the various rings and the stuffing box face, and that the axial force F is transformed into a radial force P, which is distributed evenly to the outer surface of the shaft being sealed and the inner surface of the stuffing box.

Explanation of the attached figures

The useful model is explained with the help of the attached figures, where:

Figure 1 shows a three-dimensional view of a diagonally braided packing;

figure 2 shows the cross-section of a first exemplary embodiment of the diagonally braided packing;

figure 3 shows the cross-section of a second exemplary embodiment of the diagonally braided packing;

Figure 4a shows a cross-section of a ring made of a diagonally braided packing before its installation in the stuffing box;

figure 4b shows a package of rings made of diagonally braided stuffing after being installed in the stuffing box;

figure 5 shows a stuffing box in which rings made of diagonally braided packing are installed.

Examples of implementing the utility model

Figure 1 shows the spatial image of the diagonally braided packing with a rectangular trapezoidal cross-section. The diagonal braided packing thus formed is cut to the required length, from which sealing rings 3 are made.

In fig. 2 shows a first exemplary embodiment of a diagonally braided filling with a cross-section in the shape of a rectangular trapezoid, which includes first 1.1, second 1.2, third 1.3 and fourth 1.4 fillings inserted into a carrier yarn 2. The rings 3, according to fig. 5, are placed in the stuffing box 4. The rings 3 have a cross-section in the shape of a rectangular trapezoid, formed between a large upper outer base 3a, which contacts the inner surface of the stuffing box 4, a small lower inner base 3c, which contacts the outer surface of the compaction shaft 5, a vertical side 3c making upper and lower right angles with the large upper outer base 3a and with the small lower inner base 3c, and an inclined side 3d making an acute angle with the large upper outer base 3a and an obtuse angle with the small lower inner base 3c. The stuffing box 4 is closed with a lid 6. The first fillings 1.1 of the inserted yarns 2 have 80 threads. The second 1.2, third 1.3 and fourth 1.4 fillings consist of a smaller number of inserted threads. The second filling 1.2 consists of 60% to 80%, preferably 70-75%, of the number of threads involved in the first filling 1.1. The third filling 1.3 consists of 35% to 50%, preferably 40-45%, of the number of threads involved in the first filling 1.1. The fourth filling 1.4 consists of 5% to 15%, preferably 7-10%, of the number of threads involved in the first filling 1.1.

From Figure 2, it can be seen that the cross-section of the diagonally braided packing is a rectangular trapezoid, which has a large diagonal and a small diagonal: The large diagonal starts from the end of the upper outer base 3a, where the acute angle is formed between it and the inclined side 3d of the rectangular trapezium and ends at the end of the small lower inner base 3c, where the lower right angle between it and the vertical side 3c is formed. The small diagonal begins at the end of the large upper outer base 3a, where the upper right angle formed between it and the vertical side 3c is located, and ends at the end of the small lower inner base 3c in the region of the obtuse angle. A part of a right trapezoid includes a right isosceles triangle whose right angle coincides with the upper right angle, its legs are parts of the large upper outer base 3a and of the vertical side 3c, and its hypotenuse is the row of fillings, which is parallel to the large diagonal and precedes it . All fillings in the mentioned right-angled isosceles triangle are the same and are first fillings 1.1, which have a maximum number of threads - 80 pieces. At the intersection of the large diagonal with the small diagonal of the rectangular trapezoid, a third filling 1.3 is located, on both sides of which, along the large diagonal, a second filling 1.2 is located, and after each of the second fillings 1.2 in the direction of both ends of the large diagonal, there are two first fillings each 1.1. In the next row of fillings, which is located on the side of the obtuse angle and is parallel to the large diagonal, there are three types of fillings. A second filling 1.2 is located close to the inclined side 3d, after which, towards its other end to the small lower inner base 3c, two thirds filling 1.3 and two fourth fillings 1.4 are successively arranged. In the next row of fillings, which is parallel to the large diagonal and precedes the obtuse corner of the rectangular trapezoid, in the direction from the inclined side 3d to the lower base 3c, one third filling 1.3 and two subsequent fourth fillings 1.4 are placed successively. In the corner where the obtuse corner of the rectangular trapezoid is, a fourth filling 1.4 is located.

In fig. 3 shows a second exemplary embodiment of a diagonally braided packing having a rectangular trapezoidal cross-section. Fillings are located along the large diagonal of the rectangular trapezoid as follows: third filling 1.3 is located at the intersection of the large diagonal of the rectangular trapezoid with its small diagonal. On both sides of the third filling 1.3 along the large diagonal, one second filling 1.2 is placed, and after the second filling 1.2 in the direction towards its ends, one first filling 1.1 is placed. In the next row of fillings, which is located on the side of the obtuse angle and is adjacent and parallel to the large diagonal, two types of fillings are placed, and a third filling 1.3 is located near the inclined side 3d, after which, in the direction of its other end to the small lower inner base 3c, two quarter fillings 1.4 are arranged successively. In the corner where the obtuse corner of the rectangular trapezoid is, a fourth filling 1.4 is located.

It is possible to increase or decrease the number of inserted threads in the second 1.2, third 1.3 and fourth 1.4 fillings located in the lower obtuse corner of the cross-section of the diagonally braided filling. In this way, the material is "retracted" to the center of the cross-section of the diagonally braided stuffing and the rectangular trapezoid is formed.

After the pad is braided, it goes through the usual calendering operation, the calender rolls being designed to copy the rectangular trapezoidal profile of the diagonally braided pad.

Using the utility model

The diagonally braided packing is used in the same way as all packings known before the creation of this utility model are used, by making rings 3 from the packing. Sealing with the rings 3 made from the diagonally braided packing according to the utility model is realized as follows .

The diagonally braided stuffing is cut into pieces of the required length. Rings 3 are made from the cut pieces, according to fig. 4a. The rings 3 are installed in the stuffing box 4, with the small inner base 3c of the rectangular trapezoid, in this case the narrow side of the packing, must face the surface of the shaft to be sealed 5. The number of rings 3 is determined in advance according to the structural depth of the stuffing box 4 .The size of the selected packing is determined by the differences in the inner diameter of the stuffing box 4 and the outer diameter of the shaft to be sealed 5, divided by two. It depends, to a large extent, on the speed of rotation of the sealing shaft 5 and on the pressure of the sealing fluid. Different packing sizes are used for shafts with a wide range of diameters. For example, a packing with a section of 10 x 10 mm is used to seal shafts with a diameter of Ф30 to Ф80.

By means of the gland cover 6 and the gland studs, the required compressive axial force F is provided. The axial force F is transformed into a radial force P acting on the inner surface of the stuffing box 4 and on the outer surface of the shaft to be sealed 5. Due to the fact that the packings are a braid with plastic properties, when its studs are tightened, by means of the packing cover 6, the applied axial force F is transformed into a radial force P, causing friction on the inner surface of the stuffing box 4 and the outer surface of the sealing shaft 5. As a result of the friction, the axial force F in the depth of the stuffing box 4 decreases. It has been found experimentally that when installing more than five rings 3, the rings located after the fifth ring 3 in the depth of the stuffing box do not carry any axial force.

Claims (1)

A diagonally braided packing made up of a plurality of fillings of varying thread count woven into a carrier yarn, wherein the packing has a trapezoidal cross-section whose large outer upper base is intended to contact the inner surface of the stuffing box and its small inner lower base is intended to for contact with the shaft being compacted, with the packings of different numbers of threads arranged asymmetrically along the packing cross-section, and the packings with the highest number of threads located at the top of the trapezoidal cross-section, while the packings with the lowest number of threads are located in the lower part of the trapezoidal section, characterized in that the trapezoidal cross-section of the diagonally braided pad is in the form of a right-angled trapezoid having a large diagonal and a small diagonal, the large diagonal starting from the end of the upper outer base (3a) where it is formed the acute angle between it and the inclined side (3d) of the rectangular trapezoid, and ends at the end of the small lower inner base (3c), where the lower right angle is formed between it and the vertical side (3c), and the small diagonal begins at the end of the large upper outer base (3a) where the upper right angle is located between it and the vertical side (3c) and ends at the end of the small lower inner base (3c) in the region of the obtuse angle, where part of the right trapezoid includes a right isosceles a triangle whose right angle coincides with the upper right angle, its hips are parts of the large upper outer base (3a) and of the vertical side (3c), and its hypotenuse is the row of fillings that is parallel to the large diagonal and precedes it, where all fillings in the mentioned isosceles right triangle are the same and are performed as first fillings (1.1) that have the maximum number of threads, where at the intersection of the large diagonal of the right-angled trapezoid with its small diagonal, a third filling (1.3) is located, which consists of 35% to 50% of the number of threads involved in the first filling (1.1), and on both sides of the third filling (1.3), in the large diagonal are located one second filling (1.2) and after each of the second fillings ( 1.2), in the direction of the two ends of the large diagonal, are located at least one first filling (1.1), and the second filling (1.2) consists of 60% to 80% of the number of threads participating in the first filling (1.1), at whereas the fillings located next to the inclined side (3d) in the direction from the large upper outer base (3a) to the small lower inner base (3c) are fillings with a decreasing number of threads, and in the region of the obtuse angle to the small inner lower base (3c), a fourth filling (1.4) is placed, which has a minimum number of threads and consists of 5% to 15% of the number of threads of the first filling (1.1), where each of the following large diagonal rows of fillings located on the side of the obtuse angle, at its end next to the inclined side (3d) contains a filling with a higher number of threads compared to the filling located at its end located next to the lower inner base (3c)