WO2007115508A1

WO2007115508A1 - A method and conduit for passing cable through smoothly

Info

Publication number: WO2007115508A1
Application number: PCT/CN2007/001172
Authority: WO
Inventors: Jun Xu
Original assignee: Jun Xu
Priority date: 2006-04-11
Filing date: 2007-04-11
Publication date: 2007-10-18
Also published as: CN101427433B; GB0820607D0; GB2450851B; CN1832282A; GB2450851A; CN101427433A

Abstract

A method and conduit for passing cable through smoothly, used for passing the cable through soomthly in different directions in one plane or two unparallel planes between two buildings, wherein the method including: choosing the curved path and conduits of the less accumulative bending angle when the equivalent bending radius of them meet the minimum requirement, and choosing the curved path and conduits of the longger equivalent bending radius when the accumulative bending angle is not affected.

Description

Method and pipe fitting for smoothing cable pipeline

The invention relates to a method and a pipe fitting which are applied in building electrical piping, building integrated wiring or decoration engineering, and making the cable pipeline unblocked. In particular, the method and the tubular member are curved pipe methods and tubular members for smoothly changing the direction of the cable conduit between the connected building bodies in the plane of a building body or in which the two surfaces are not parallel to each other. Background technique

The use of various cables in modern buildings is increasing, and cable changes and additions often occur during the life of the building. These growing demands place higher demands and expectations on the design and construction quality of cable runs, especially the patency and multiple reuse of pipes. With the adoption of new building materials and building technology, the thickness of the building body, especially the interior wall of the building, is significantly reduced, and the space for laying the pipeline in the building body is more and more restricted. The design and construction techniques present new challenges.

There are many factors that affect the smooth flow of the pipeline. The present invention focuses on the following problems.

When the pipeline changes direction between the two buildings, how to achieve a turning of not less than 10 times the bending radius of the pipe diameter when the deflection distance is limited; how to reduce the cumulative turning angle of the entire pipeline, and reduce unnecessary unnecessary Roundabout.

Regarding the bending radius problem, in the current Chinese national standard for building electrical piping and integrated wiring, the minimum bending radius of the dark piping is required to be not less than 6 times the piping diameter, preferably 10 times or more. From the point of view of wiring construction, the larger the bending radius, the easier it is to lay and replace the cable passing through the electrical piping, and the cable is less damaged when it is laid.

However, in practice, especially in renovation projects, walls and floors have many restrictions on the laying space of the pipes. When the pipe is turned between the floor and the wall, or between the two walls, the deflection of the pipe in the direction perpendicular to the surface of the building is limited by the thickness of the building, the structure of the building and the requirements of the construction process. Vertical plane bending method, it is very difficult to achieve a bending radius of 10 times or more, which is even impossible under many construction conditions.

Figure 1 shows a vertical plane elbow method in which the pipe is redirected between two mutually perpendicular building bodies, which is a cross-sectional view along the central axis of the pipe. a and b are the maximum deflection limit distances allowed by the tube in a direction perpendicular to the surface of the two building bodies, that is, the vertical deflection limit distance, and Π 1 and Π 2 are the inner two restriction faces, and their intersection is the term Introducing the limit line. In Fig. 1, the limit line c is shown as one point, and the intersection line h of the two outer limit faces is shown as another point, D is the pipe diameter, and r is the intermediate variable. Then, the maximum bending radius Rmax of this vertical plane elbow is determined by the following equation group -

Rmax = r+D/2; r ² = (ra) ² + (rb) ²

Where r^a, r^b Figure 2 shows a more general situation in which the surfaces of two building bodies are connected at an angle. D is the pipe diameter of the pipe, a and b are the vertical deflection limit distances, Φ is the angle between the surfaces of the two buildings, and Φ 1, Φ 2 and r are intermediate variables. The maximum bending radius Rmax of the vertical plane bend is determined by the following equations:

Rmax = r+D/2; Φ = Φ 1+ Φ 2; εϊη Φ 1 = (ra) /r _; εϊη Φ 2 = (rb) /r

Where r a, r^b, Φ 1 90° , Φ 2 90° , sin is a sine function

When Φ = 90°, the above equations are reduced to the previous set of equations.

For the common case of Φ = 90°, we look at the diameter D used in the actual project. Let us look at the required vertical deflection limit distances a and b in order to obtain a bend radius of 10 pipe diameters. The calculated values in the table are accurate to 0.1 cm, and all units are in centimeters ( _cm ).

From the data in the table, it is clear that for the actual construction or cable construction in the construction, in order to achieve a bending radius of 10 times, when one of the buildings, such as the floor, has a vertical of no more than 3 cm When the deflection is limited, the other building body needs to have a vertical deflection limit of 8. 8 cm or more. This requirement is difficult to meet. That is to say, according to the conventional vertical plane bending method, it is very unrealistic to realize a bending pipe with a bending radius of 10 times or more. For applications that require larger diameters or require larger bend radii, the difficulty is even greater.

Another issue that needs to be addressed is that there are still many different path schemes to achieve the same large bend radius, and their resistance to the cable, that is, the smooth passage of the cable, is different. For each elbow that has no significant difference in bending radius, what other factors are affecting the patency of the cable line?

Summary of the invention

The method and the pipe fitting provided by the invention can solve the problem that the bending radius of a large bending radius of 10 times or more is difficult to be realized due to the limitation of the thickness of the building body, the structure of the building and the requirements of the construction process, and the path can be saved as much as possible, thereby reducing unnecessary The resistance generated by the roundabout. These measures as a whole ensure the smooth flow of the pipeline. At the same time, in order to facilitate large-scale industrial production, the structure of the pipe fittings was also optimized. First, the related concepts such as virtual pipelines should be further explained.

In various building electrical national standards, there are certain requirements for the minimum bending radius of the cable elbow. For an ideal circular arc or a smooth curved elbow, the concept of the bending radius can accurately reflect the actual bending effect. However, there are various objective conditions in the actual pipeline in the project, such as the small diameter of the pipe joint. Misalignment butt joints, deformation of pipes, and non-smooth connections between pipe sections. A typical non-smooth connection is a line of angles at which the two pipe segments are connected at an angle. These objective existences will inevitably lead to some singularities in the pipeline. The bend radius at the singularity is very significantly smaller than the bend radius of other pipe segments, and in some cases even zero. The concept of singularity is defined in more detail in the terminology.

Figure 3 is a schematic diagram of a pipeline with singularities. The straight pipe sections on both sides of the singular point S1 are connected by the angle θ 1 , and the bending radius at the singular point S1 is zero; the singular point S2 is connected to the straight pipe section by a small arc segment with a very small bending radius. The bending radius at point S2 is smaller than the pipe diameter.

The existence of the singularity makes the value of the original bend bend radius no longer accurately reflect the true bending effect of the cable bend. In fact, the presence of certain singularities has little effect on the patency of cable runs, while the presence of other singularities has a fatal effect on the patency of cable runs. The right angle bend we often see in engineering is a singularity that seriously affects the smoothness of cable runs. Although the singular point S1 and the singular point S2 exist in the curved pipe shown in Fig. 3, the angle of the Θ 1 is small, and the turning angle of the curved pipe section having a very small bending radius at the singular point S2 is also small, and the circle in the figure is A partial enlarged view at the singular point S2. The impact of these two singularities on the patency of the cable runs is minimal.

The introduction of the virtual piping concept is to more accurately measure the bending effect of the actual bend.

Figure 4 is a cross-sectional view along the axis of the tube. A virtual pipe L is introduced into the elbow where the singularity exists, and the pipe diameter Dv is smaller than the inner diameter of the elbow. There are no more singular points on the virtual pipeline L, and the bending radii of each pipe segment are Rl, R2, R3 and R4.

In Fig. 5, after we introduce a virtual pipeline L in the elbow where the singularity S3 exists, the singularity still exists, but the singular point S3 with the original bending radius of zero is replaced with the singular point S4 whose bending radius is not zero. .

Can the virtual line after filtering out the singularities that have little effect on the patency of the cable line accurately reflect the bending effect of the actual bend pipe? In fact, there can be any virtual pipeline in the same elbow pipeline. They have different paths and therefore different bending radii. Therefore, it is necessary to find a virtual pipeline with the largest bending radius to represent the bending effect of the actual pipeline. This is the optimal virtual pipeline.

The introduction of the virtual piping concept, like a sieve, filters out those singularities that have little impact on the patency of the cable runs, while retaining those that have a greater impact on the patency of the cable runs. point. The choice of the diameter of the virtual pipe, or the choice of the virtual-to-real ratio, can be regarded as the size of the mesh of the sieve. The larger the virtual-to-real ratio, the smaller the sieve opening and the fewer singularities that are screened out. On the contrary, the more. 07 001172 With the optimal virtual pipeline, we can quantitatively evaluate the bending effect of the actual elbow pipeline with the concept of the optimal virtual pipeline bending radius, ie the equivalent bending radius.

There is also a need to further define the smooth connection between the two pipe segments.

The so-called smooth connection between the various pipe sections of the cable run is a vague statement. The ideal connection is a tangent connection. But in practice, it is not realistic to require absolute tangent connections. It is more economical and practical to allow the singularity of the connection between the pipe segments, as long as the influence of this singularity on the patency of the cable pipe can be neglected to some extent. A more precise meaning is that the presence of this singularity does not cause the equivalent bend radius of the two pipe sections being connected as one integral pipe to be less than the respective equivalent bend radii of the two pipe sections.

Further, for the purpose of the present invention, the pipe segments referred to herein are all elbows or straight pipes having an equivalent bending radius of not less than 10 times the pipe diameter. Our requirement for a smooth connection is that the equivalent bend radius of the two pipe sections connected as a whole pipe is still not less than 10 times the pipe diameter. In other words, whether the connection is tangent or singular, their effect is approximately the same. This is the concept of an equivalent smooth connection. Its introduction facilitates the clear expression of technical solutions.

First, pseudo three-dimensional elbow

The so-called pseudo-stereoscopic elbow is a three-dimensional elbow formed by the equivalent smooth connection of two plane elbows whose planes are not parallel. The plane elbow mentioned here has a broader meaning as defined in the terminology. The projection of the central axis of the three-dimensional elbow on a plane perpendicular to the plane of the two flat bends is a fold line connecting the two straight segments at an angle. Figure 6 is a perspective view of a pseudo-stereoscopic elbow.

In Fig. 6, the equivalent bending radii of the plane elbow 1 and the plane elbow 2 are not less than 10 times the diameter of the pipe, and they are equivalently smooth at 0 o'clock.

The connection between the two flat bends can be a fixed connection or a wider range of active connections.

Figure 7 is a three-view view of the pseudo-stereoscopic elbows in which the planes are fixedly connected and the planes are perpendicular to each other. R is the bending radius and D is the pipe diameter. In the side view thereof, the central axes of the two planar bends are perpendicular to each other.

Figure 8 is a three-view view of a pseudo-stereoscopic elbow in which two planar elbows are movably connected. R is the bending radius and D is the pipe diameter. The active connection allows the pseudo-stereoscopic bend to accommodate various angles between the surfaces of the building.

Figure 9 shows the state of the articulated pseudo-stereo elbow at different angles.

When the above angle is adjusted to 180°, the articulated pseudo-stereoscopic elbow becomes an S-shaped flat elbow. Figure 10 shows the situation after the flattened elbow connected by the straight-through activity is flattened. R is the bending radius.

The equivalent bending radius of the pseudo-stereoscopic elbow depends only on the equivalent bending radius of the two planar elbows forming the pseudo-stereoscopic elbow, and has no relationship with the vertical deflection limit distance of the building body. In order to achieve a three-dimensional turning of the equivalent bending radius of 10 times or more of the pipe diameter, it is required that the equivalent bending radii of the two plane bending pipes are more than 10 times the pipe diameter. The pseudo-stereoscopic elbow with simple structure is relatively easy to process and produce. In the application, the two plane elbows are parallel to the surfaces of the two building bodies, and the turning of the bending radius of 10 times or more can be easily realized.

However, there are some obvious weaknesses in the actual effect of this scheme.

First, it does not take advantage of the deflection space allowed by the building, which is the vertical deflection limit of the building. The desired equivalent bending radius is achieved by means of a meandering curve in a plane parallel to the surface of the building. It is less effective in saving the path than the one that will be described later.

Another problem is that when multiple pseudo-stereoscopic bends are required to be laid side by side, the spacing between the bends is too large.

Figure 11 shows the situation in which three pseudo-stereoscopic elbows are laid side by side, showing a front view and a top view. For a common conduit with a pipe diameter D of 2 cm, when the bending radius R of the pseudo-stereoscopic elbow reaches 10 times the pipe diameter, that is, 20 cm, the horizontal spacing E between the three pseudo-stereoscopic elbows laid side by side is approximately 9cm. Obviously, this spacing is too large for the case where a row of conduits is drawn from several outlets that are often encountered in the project.

Second, the three-dimensional bend

A major improvement over the weakness of the pseudo-stereoscopic bends described above is that we want to take full advantage of the roundabout space provided by the vertical deflection limit of the building.

In order to better understand the effect of this improvement, the following is another indicator that affects the patency of the cable line, that is, the cumulative turning angle, for analysis.

The introduction of the concept of cumulative turning angle is to more accurately evaluate the difference between different curved paths with the same bending radius, and this difference has a certain positive correlation with the degree of obstruction of the cable through the elbow.

The following explains the common L-bend and S-bend and their variants.

To simplify the diagram, each elbow is represented by a thick line, and all elbows are flat elbows.

Figures 12 and 13 show a right angle L-bend and its variants. For the same bend radius R, four different bend paths are given.

Bend B1 is the most common type of elbow with a cumulative turning angle of 90°.

The elbow B2 is composed of two sections of elbows and a section of straight tubes sandwiched between them. The cumulative turning angle is the sum of the turning angles Ψ 1 and Ψ2 of the two sections of elbows, in this case also 90°.

The elbows B3 and B4 use three-stage elbows to complete the required 90° turns. Their cumulative turning angles are the sum of the turning angles of the respective three-segment bends, in this case 150° and 210 respectively. ° .

We use AA1, AA2, AA3, M4 to indicate the cumulative turning angle of bends B1 to B4. From the above values we get the following relationship: AA1 = AA2 < AA3 < AA4.

Under the same conditions, there are similar relationships between the obstructions of the four different paths to the passage of the cable. If Z1, 12, Z3, Z4 are used to indicate the degree of obstruction of the bends by the bends B1 to B4, then Experience we get the following relationship: Z1 Z2 <Z3 < Z4.

It can be seen that the bends B1 and B2 are smaller and more excellent paths with respect to the bends B3 and B4.

Figure 14 shows the S-bend and its variants. In the figure, the tangential extension lines at both ends of the S-shaped elbow are parallel to each other. For the same bend radius R, two different bend paths are shown.

The elbow B5 consists of two 90° elbow connections with a cumulative turning angle of 180°.

The elbow B6 is composed of two sections of elbows and a section of straight tubes sandwiched between them. The cumulative turning angle is the sum of the turning angles of the two sections of elbows, that is, twice the Ψ6. When Ψ6=45°, the cumulative turning angle is 90. . Obviously, as the value of Ψ6 is further reduced, the cumulative turning angle is also reduced, and the entire S-bend becomes smoother and the patency is better. In theory,

The value of Ψ 6 can be close to zero.

A more in-depth mathematical analysis can provide the following conclusions:

The minimum limit of the cumulative turning angle of the elbow is the angle between the extension lines at both ends of the elbow.

For the flat elbows whose extension lines are not parallel to each other, the elbow method of B1 and Β2 in Fig. 12 above can be used to obtain the elbow with the smallest accumulated turning angle or the optimum cumulative turning angle. However, for a flat elbow in which the extension lines are parallel to each other and the extension line is not in a plane, the minimum cumulative turning angle is only a theoretical limit. In practical applications, the curved path should be reasonably selected according to different construction conditions to obtain a relatively small cumulative turning angle.

Before introducing the three-dimensional elbow, look back at the first introduction of the vertical plane elbow scheme. As shown in Figure 15, in order to obtain a larger bend radius, the vertical deflection limit can be used as much as possible to provide the bypass space. However, since the depth of the socket bottom box to be reached by the usual cable pipe is limited from the wall surface, it is inevitable to sacrifice the turning angle while increasing the bending radius. In Fig. 15, due to the positional limitation of the bottom case 24, Ψ01 and Ψ02 increase as R increases.

If the minimum requirements for the bend radius of the pipe are still not met after making full use of the vertical deflection limit, or if the cumulative turn angle becomes too large, then other options must be considered. In the case of Fig. 15, when Ψ 01+Ψ02 180°, even if the bending radius R reaches the desired value, this is not an ideal solution.

Then we expect the three-dimensional elbow to have a cumulative turning angle that is smaller than the cumulative turning angle of the pseudo-stereoscopic elbow. Of course, this comparison is based on the two port directions, ie the extension line direction is the same.

Figure 16 is a perspective view of a three-dimensional elbow.

On the surface, the pseudo-stereoscopic bends in Figures 16 and 6 are similar. What is the difference between the three-dimensional bending scheme compared to the pseudo-stereo elbow?

Figure 17 is a three-view view of a three-dimensional elbow. Where Rx, Ry and R _Z are the equivalent bending radii of the projection of the pipe section 5 on the three projection surfaces, respectively. By comparing Fig. 7, it can be seen that the side view in Fig. 17 is significantly different from the side view in Fig. 7. It should be added that, in order to facilitate the expression of the elbow structure, the viewing angles of FIGS. 17 and 7 are selected by using two mutually perpendicular building body surfaces as front and side projection views, and the side views are elbows. On the surface perpendicular to the two building bodies Projection on the plane.

In the side view in Fig. 17, the equivalent bending radius Rz of the projection of the pipe section 5 satisfies the following relationship: 0 < Rz^Rmax, where Rinax is a vertical plane elbow calculated from the vertical deflection limiting distances a and b The maximum bend radius. Assume that the equivalent bending radius of the three-dimensional elbow that we need to achieve is the target value of R, and R>Rmax, while the pipe section 3 and the pipe section 4 in Fig. 17 are plane elbows, and their equivalent bending radii are also R.

Since Rz>0, the equivalent bending radius of the pipe segment 5 is not less than ^ Rx and Ry can be less than ^

Further comparisons require flattening the three-dimensional bend. The pseudo-stereoscopic elbow described above is composed of two flat elbows, and its flattening is very easy. However, the flattening of the three-dimensional elbow introduced here requires the introduction of the concept of a curved surface.

The curved surface referred to herein is formed by the central axis of the three-dimensional elbow extending in a direction parallel to the line of intersection of the surfaces of the two building bodies. Figure 18 is a schematic view of the curved surface on which the three-dimensional elbow is located. For ease of understanding, reference lines are added to the surface that are parallel to the intersection of the two building surfaces, which respectively intersect the central axis of the three-dimensional elbow. The tangent at any point on the central axis is not parallel to the line of intersection of the two building surfaces, which is another feature of the desired three-dimensional bend.

After flattening the surface, the three-dimensional elbow becomes the plan view of Fig. 19. R is the bending radius. The dotted line in the middle represents the intersection of the surfaces of the two buildings.

Compare the pseudo-stereoscopic elbows and the three-dimensional elbows with the same port direction and compare them together, as shown in Figure 20. One end of the pseudo-stereoscopic bend B7 P7 and the P8 of the three-dimensional elbow B8 coincide, and the tangent lines thereof also coincide; the tangent lines of the other ends Q7 and Q8 are parallel to each other. As can be seen from the figure: The cumulative turning angle of the pseudo-stereoscopic bend B7 Ψ 7-Ψ71+ Ψ72, the cumulative turning angle of the flattened curved B8 Ψ8=Ψ81+Ψ82. Where Ψ 7 is a fixed value, which is determined by the angle between the extension lines of the two ports of the pseudo-stereoscopic bend Β7 and the intersection of the planes of the two plane bends. The value of the cumulative turning angle Ψ8 of the three-dimensional elbow Β8 is a variable value. Further analyzing with reference to Fig. 17, under the condition that the direction of the two ports of the three-dimensional elbow and the bending radius of the three-dimensional elbow are kept constant, when Rz is increased, Ψ8 is decreased. Although Ψ 7> Ψ8, the relationship between the actual cumulative turning angle of the three-dimensional bend Β8 and Ψ7 is not certain.

Related experiments show that there are countless three-dimensional elbows that can achieve the same bending radius turning. Their cumulative turning angle is smaller than the cumulative turning angle of the pseudo-stereoscopic elbow, the required detour space is smaller, and the smoothness of the pipeline is more high.

Although the three-dimensional bending scheme is better than the pseudo-three-dimensional bending scheme, new problems have emerged. Except for some of the features we have mastered, from the above description, we cannot clearly state the specific structure of the three-dimensional elbow that we expect to achieve a smaller cumulative turning angle, especially how to accurately measure and control during processing and production. The bending radius and bending direction of such a complicated curved pipe. Obviously, this type of structure is unclear, and there are too many variable three-dimensional bends that are difficult to industrially mass-produce.

From the point of view of industrial application, in order to make full use of the deflection space provided by the building body, it is unrealistic to specifically process a specific, ideal three-dimensional bend for different vertical deflection limit distances. We need a new solution, which has a simple structure of pseudo-stereoscopic bends to facilitate mass production and processing, and has the effect of being close to the ideal three-dimensional bend.

Third, rotating pseudo three-dimensional bending scheme

The basic scheme of the rotating pseudo-stereoscopic elbow scheme is: by adjusting the angle between the two plane elbows of the pseudo-stereoscopic elbow and the surface of the respective building body, the pseudo-stereoscopic elbow can fully utilize the vertical deflection limit distance of the building body, Achieve the effect of using the ideal three-dimensional elbow.

The following is explained by several figures.

Fig. 21 is a schematic view showing the flattening of a pseudo-stereoscopic bend having a bending radius of R in each of the typical portions. The pseudo-stereoscopic elbow is represented by a thick solid line, the straight line f is the intersection line of two planes, and the ray m and the ray n are perpendicular to the intersection line f in two planes, respectively, and respectively belong to the circle to which the two plane arc segments belong. Tangent, the two planes of the pseudo-stereoscopic elbow are perpendicular to each other. The rotation of the pseudo-stereoscopic elbow described below is carried out with the ray m and the ray η as the rotation axes, respectively. During the rotation of one of the axes, the other ray is translated in its own plane and remains perpendicular to the intersection f.

In order to clearly show the correspondence before and after the rotation, the joint point 0 and the two end points (P and Q) of the two plane bends of the pseudo-stereoscopic elbow are represented by eye-catching dots, and the circle to which the two plane bends belong Indicated by a dotted line.

The rotation of the pseudo-stereoscopic elbow is completed in two steps: with the ray m as the rotation axis, rotating in the direction of the ray n; and the ray n as the rotation axis, rotating in the direction of the ray m. These two rotations are not in order.

Figure 22 shows a more general case. Only one of the plane bends 0P of the pseudo-stereoscopic elbow is shown. The OP is not a simple arc shape, and its equivalent bending radius is R, but there is no OP. The tangent of a point is perpendicular to the intersection f. In order to complete the rotation, a circular arc PPe with a bending radius of R is added, which is connected to the elbow OP at point P, and the tangent of the Pe point is perpendicular to the intersection f, so that there is a rotation axis m passing through the Pe point. This arc PPe is the extended arc defined in the terminology. As described in the definition, the extended arc PPe and the elbow 0P are in one plane and on the same side of the tangent to point P.

Figure 23 is a front elevational view and a plan view of the pseudo-stereoscopic elbow of Figure 21 after rotation. For convenience, the intersections f in the two views are coincident. ω πι and ω _η are the rotation angles of the ray _m and the ray _n , respectively. The straight line c is parallel to the intersection line f, and the distances from the two planes before the rotation are a and b, respectively, which are the vertical deflection limit distances allowed by the building body.

As can be seen from the figure, after the rotation, the circle indicated by the dotted line of the two plane bends becomes an ellipse in the front view and the top view. Pipe segment 0P is a part of the elliptical arc in the front view and a straight line segment in the top view. Pipe segment 0Q is part of an elliptical arc in the elevation view and a straight line segment in the front view.

Figure 24 is a left side view of the pseudo-stereo-bend after rotation. The intersection f and the straight line c in Fig. 23 are shown as two points in the figure, and the pipe segment 0P and the pipe segment 0Q are still part of the two elliptical arcs in the left view, respectively, which are tangently connected at the 0 point.

It should be noted in Fig. 23 and Fig. 24 that the intersection of the two planes after the rotation is g, and the intersections P and Q of the ray m and the ray n before the rotation of the pseudo-stereoscopic bend become the intersection point Pm after the rotation, respectively. And Qn, pseudo-stereo bends after rotation in Pm and 7/001172

The tangential direction of the Qn point is the tangential direction of the P and Q points before the pseudo-stereoscopic elbow is rotated, that is, only a part of the pseudo-stereoscopic elbow after the rotation is required, that is, the part from the point Pm to the point Qn, also called As an effective part, the same turning purpose of the pseudo-stereoscopic bend before the rotation can be completed. Therefore, in the following Figs. 25 and 26, the excess pipe segments PPra and QQn are indicated by thick dashed lines, respectively.

Figure 25 is a plan view of the two plane bends 0P and 0Q in rotation after their rotation.

The two views are stitched together so that their intersections g coincide, and the endpoints 0 coincide, and Figure 26 is obtained. Figure 26 is actually a plan view of the pseudo-stereoscopic bend after the new intersection line g is flattened. It should be noted that there are two intersection lines f in Fig. 26, which respectively reflect the view position of the actual intersection line f in two different planes, and the intersection line f perpendicularly intersecting the ray m is located at the section 0P of the section In the plane, the intersection line f perpendicularly intersecting the ray n is in the plane of the tube segment 0Q.

In Fig. 25 and Fig. 26, vm and Ψη are the turning angles of the plane elbow pipe segments OPm and OQn after the pseudo-stereoscopic elbow rotation, respectively, and the cumulative turning angle of the effective portion after the pseudo-stereoscopic elbow is rotated 3⁄4^3⁄4^+ ¥1. The meanings of the other marks are the same as those of Fig. 23. 23, the solid geometry of FIG. 27 is obtained, where f and g are the intersection lines f and gm and n in FIG. 23, respectively, and the rays m and n am and ω _η in FIG. 23 are respectively in FIG. The rotation angles c _m and ω _η Ψ πι and Ψη are the turning angles Ψΐη and Ψη in Fig. 26, respectively. After a simple operation, we get the following equations:

Ctg ψη = tgcom · cos ω η;

Ctg ΨΙΉ = tg ω η · cos ωπι

Where 0 ωπι<90° , 0 ωη<90° , 0< vm 90° , 0<Ψη 90° cos is a cosine function, tg is a tangent function, and ctg is a cotangent function.

Look at the special case. When _m =0, the ray m is not rotated.

Ψη=90° vm=90° - ωη

Then, ψ = 180° - ωη, that is, the larger ω _η , the smaller the Ψ.

By further analysis, by increasing the values of ωπι and ω _η , the cumulative turning angle can be reduced.

To calculate the maximum values of cm and ω _η , some reasonable limits must be made:

0 a<R 0 b<R (Ra) ² + (Rb) ² > R ² 0 m<90° 0^ω _η <90°

When ωιη is 0, the maximum value of ω _η satisfies the following equation:

(Ra/sinon) ² + (Rb) ² = R ²

Similarly, when ω _η is 0, the maximum value of ωηι satisfies the following equation. - (Rb/sin m) ² + (Ra) ² = R ²

A special case is analyzed: The rotation of the pseudo-stereoscopic elbow causes the midpoint 0 of the pseudo-stereoscopic elbow, that is, the point at which the two planar elbows intersect, just falls on the limit line c in FIGS. 23 and 24. That is to say, the distance from the 0 point after the rotation to the two planes of the pseudo-stereoscopic elbow before the rotation is exactly the corresponding vertical deflection limit distances a and b, respectively. Figure 28 shows the schematic of the tube segment OQn. Fig., where _R is the bending radius, and the distance between the two planes of the pseudo-stereoscopic elbow before the rotation of 0 point is exactly the corresponding vertical deflection limit distances a and b, respectively, f is the intersection line f in Fig. 22, n is a diagram The ray η, ω _η in 23 is the rotation angle ωη in Fig. 23, and Ψη is the turning angle Ψη in Fig. 26. After calculation, the relationship is obtained: (R- R' coswn) sin n Similarly, there is (R- R, cosvm) sin om = b.

Combined with the two equations obtained from Fig. 27, the final turning angles 3⁄4rm and Ψη satisfy the following equations: (R-R · cos Ψ η) είηωη = a;

(R-R■ cos ΨΙΏ) sin ωπι = b;

Ctg ψη = tgcom · cos n;

Ctg m = tg ω n · cos m

Where 0 wm<90° , 0 ωη<90° , 0< vm 90° , 0< Ψη 90° , sin is a sine function, cos is a cosine function, tg is a tangent function, and ctg is a cotangent function.

In the above special case, the cumulative turning angle of the elbow can be calculated by the values of 1?, a, b.

Next, analyze the bending radius of the curve in Fig. 24. Since the curves 0P and 0Q are part of the arcs of the two ellipse, respectively, the point 0 where they are tangently connected is the smallest bending radius in the entire curve PQ. Using the point 0 with the smallest bending radius in the curve PQ to adapt to the most difficult part of the turning of the pseudo-stereoscopic elbow in the vertical deflection limit distance a and b of the building is the special case of the rotating pseudo-stereoscopic bending scheme. The most difficult part of this is the limit line c in Figures 23 and 24.

Fourth, the selection and optimization of the piping path

In the previous scenario, we introduced the problem of achieving a three-dimensional turning of a large bending radius, and introduced another important indicator that affects the smoothness of the pipeline, accumulating the turning angle. Then, how to comprehensively consider the two factors of bending radius and cumulative turning angle in the design and construction of the actual pipeline path to the patency of the pipeline?

When the bending radius is the same, the smaller the cumulative turning angle, the better the pipe patency; when the cumulative turning angle is the same, the larger the bending radius, the better the pipe patency

Figure 29 shows the qualitative relationship between pipe patency and bending radius R and turning angle Ψ. The curve tl represents a good patency of the pipeline, the curve 1:2 represents the patency of the pipeline, and the curve t3 represents the poor patency of the pipeline.

As can be seen from the graph, when the turning angle is large enough, even if the bending radius is large, it is difficult to improve the patency of the pipe; and when the turning angle is small, even if the bending radius is small, the pipe patency is still good. The point S in the figure represents a case where the bending radius is small but the turning angle is also small, which is actually one of the singularities introduced earlier, such as S2 in Fig. 3.

Then the path design and optimization method is: Under the premise of ensuring that the minimum equivalent bending radius of the elbow meets the requirements, the path with the smaller cumulative turning angle is preferentially selected; when the cumulative turning angle is constant, the bending radius is preferred. Big path of. DRAWINGS

All of the tubes in the figures of the present invention default to a circular cross section. The following is a brief introduction of the various figures.

Figures 1 and 2 are schematic views of a vertical plane bend process with a section along the axis of the tube.

Figure 3 is a schematic illustration of the presence of singularities in the pipeline.

Figure 4 is a cross-sectional view of the virtual pipe, the section of which is along the axis of the pipe.

Figure 5 is a schematic diagram of the existence of singularities in both physical and virtual pipelines.

Figure 6 is a perspective view of a pseudo-stereoscopic elbow.

Figures 7 through 9 are three views and active state diagrams of the pseudo-stereoscopic elbows of the fixed and movably connected, respectively.

Figure 10 is a plan view of the pseudo-stereoscopic elbow connected in a straight-through manner after flattening.

Figure 11 is a front view and a top view of three pseudo-stereoscopic elbows side by side.

Figures 12 through 14 are schematic views of six flat elbow paths with different cumulative turning angles.

Figure 15 is a cross-sectional view showing the cumulative turning angle affected by the position of the socket bottom case. The profile is along the axis of the tube. 16 and 17 are respectively a perspective view and a three view of a three-dimensional elbow.

Figure 18 is a schematic view of the curved surface on which the three-dimensional elbow is located.

Figure 19 is a schematic view showing the surface of the three-dimensional curved pipe flattened.

Figure 20 is a schematic view showing the comparison of the flattened three-dimensional elbow and the pseudo-stereoscopic elbow.

Figures 21 and 22 are schematic diagrams showing the relationship between the flattened pseudo-bend tube and the rotating shaft after flattening.

Figures 23 and 24 are front, top and side views of the rotated pseudo-stereoscopic elbow.

Figure 25 is a plan view of the two planar bends of the rotated pseudo-stereoscopic elbow on their respective planes.

Figure 26 is a plan view showing the intersection of the pseudo-stereoscopic elbows along the intersection of the two planes after the rotation.

Figure 27 is a schematic diagram of a three-dimensional model for calculating the relationship between the turning angle and the rotation angle.

Fig. 28 is a schematic perspective view showing a turning angle when the midpoint 0 of the pseudo-stereoscopic elbow is rotated to the limit line. Figure 29 is a schematic diagram showing the relationship between the degree of pipe patency and the bending radius and turning angle.

Figure 30 is an axial cross-sectional view of a 45° flat elbow and three joint fittings.

Figure 31 is a schematic diagram of a method of selecting a pipeline path. Implementation

Embodiments of the present invention encompass three aspects.

First, the production and processing of pipe fittings. 1. Mass production of large bends of not less than 10 pipe diameters of different specifications and models by using molds PT/CN2007/001172 Radius pseudo-three-dimensional elbows and flat elbow fittings, in the application, through the combination of pseudo-stereoscopic elbows, flat elbows and straight tubes to achieve the required turning; 2, using bending equipment Such as elbow spring, according to the needs of the site, the flexible pipe, such as PVC pipe, metal pipe, is processed into a three-dimensional elbow or pseudo-stereo elbow with the required bending radius and turning angle.

Second, the field installation method of three-dimensional elbow or pseudo-stereoscopic elbow. In particular, how to control the rotation of the elbow to achieve a smaller cumulative turning angle.

3. How to choose the right fittings and optimized paths in various feasible piping layout schemes.

Mass production of pseudo-stereoscopic elbows and flat elbow fittings of different specifications and types can significantly improve the efficiency of construction and avoid all kinds of hidden troubles caused by on-site processing of elbows, especially the problem that the bending radius of the elbows is not up to standard. control.

Two types of fittings suitable for mold production are described below.

Pipe fittings 1: 30° -45° and 75° -90° flat bends

There are various specifications depending on the pipe diameter and the bending radius. The specifications of the pipe diameter should adopt the current national or industry standards, and the specifications of the bending radius are recommended to be used in three grades of 10 times, 15 times and 20 times. Of course, other suitable gradient values can be selected between 6 and 20 times when determining the specification.

Figure 30 shows an axial cross-sectional view of a 45° flat elbow and several fittings used. The 75° -90° plane bends have the same structure, but the turning angle is 75° -90°. In actual design and production, you can choose flat bends of 30°, 35°, 40°, 45°, 75°, 80°, 85°, 90° and so on.

The bending radius R of the plane elbow has three specifications, which are 10 times, 15 times and 20 times the diameter of the tube. Of course, other specification gradient values can also be selected.

The three joints in the figure fit tightly to the fittings of the same pipe diameter and bend radius specifications. The inner diameter of the joint matches the outer diameter of the tube. The joint 110 is used for the connection between the concentric bends, the joint 100 is used for the connection between the elbow and the straight tube, and the joint 120 is used for the connection between the reverse bends. In order to prevent the threader from clogging at the joint, the annular partition 130 in the middle of the joint is rounded. It is of course also possible to have a three-dimensionally deformed elbow joint, that is to say for the connection of two elbows that are not in the same plane. In order to identify the bending direction of the elbow joint during construction, the joint may be marked, or a rib or groove may be added in the axial direction on the inner curved side or the outer curved side of the curved portion.

In order to facilitate the rotation of the elbow at the connection point, a small straight tube may be extended at one or both ends of the flat elbow. This allows you to connect the elbow with a traditional straight-through.

In order to reduce the obstruction of the threader or the cable at the joint, the inner side of the port at both ends of the flat elbow is a circular arc port or a diagonal port. As an example, one end 61 of the planar elbow 6 in Fig. 30 is a slanted port, and the other end 62 is a circular arc port.

Pipe fittings 2: double 45° and double 90° vertical pseudo-stereo elbow

The double 45° vertical pseudo-bend elbow is composed of two 45° plane elbow joints whose two planes are perpendicular to each other. The double 90° vertical pseudo-bend elbow is composed of two 90° plane elbow joints, and the two planes are perpendicular to each other. Pipe diameters and bend radii are also available in a variety of sizes, as described in Fittings 1. The connection between the two flat bends of the double 45° and double 90° pseudo-stereo bends can be a fixed connection, as shown in Figure 7, or an active connection, as shown in Figure 8.

There are more options for the turning angle of the two flat bends, as described in the pipe fittings.

A three-dimensional elbow or a pseudo-stereoscopic elbow can achieve a relatively smaller cumulative turning angle by suitable rotation during the installation. For a complex three-dimensional elbow, a small cumulative turning angle can only be obtained by field trials.

For the pseudo-stereoscopic elbow introduced by the present invention, there is a simple and effective rotation method: the midpoint of the pseudo-stereoscopic elbow, that is, the connection point of the two planar elbows, is as close as possible to the limit line of the two building bodies.

The optimization of the piping route requires a number of factors to be considered. In addition to the bending radius and cumulative turning angle of interest to the present invention, it also includes the influence of the building structure, other piping, and the type and number of cables being worn. To get the ideal path, you must consider all factors. The method provided by the invention is a method adopted when two factors of bending radius and cumulative turning angle are considered together, that is, under the premise that the minimum equivalent bending radius of the elbow is satisfied, the cumulative turning angle is preferentially selected. Path; When the cumulative turning angle is constant, the path with a larger bending radius is preferred.

Figure 31 shows a schematic representation of the three path designs between the tube 30 on the wall and the tubes 31, 32 and 33 on the ground. Two of the 45° plane bends 9 and 10 are perpendicular to each other to form a pseudo-stereoscopic elbow. The rotation of this pseudo-stereo elbow is not shown in the figure. In order to avoid the concrete column 20, the path of the pseudo-stereoscopic bend to the pipe 31 is selected by connecting another 45° plane bend. The cumulative turning angle from tube 30 to tube 31 is 135°.

For the special case of one of the two buildings, as long as the bending radius of the cylinder is not less than the required bending radius of the elbow, the cylinder of the cylinder can be flattened, applying the aforementioned technique. The solution achieves a turning of a large bending radius. the term

Cables and wires: Wires, cables, control cables, signal cables, and various communication cables, including but not limited to coaxial cables, computer network cables, audio and video signal cables, telephone lines, and during construction and inspection. Traction cable and threader used.

Conduit: A complete pipe passage that is connected by a number of straight pipes, elbows and necessary pipe joints. A pipe has two ports, or an inlet. A straight pipe or elbow can be the simplest pipe itself.

Flat bend: An absolute flat bend is a bend that bends in only one plane. That is, the central axis of the tube is in one plane. Since a single straight tube cannot determine a single plane, a simple straight tube does not belong to the plane bend mentioned in the present invention. In view of the actual situation, the planar elbow according to the present invention includes those portions in which a part of the central axis deviates slightly from the plane, as long as the deviation ensures that a virtual pipeline can still be found in the elbow, and the virtual pipeline is absolutely The meaning of the plane bend. The definition of virtual piping is explained in detail later. Vertical flat bend: A flat elbow that is perpendicular to the surface of both buildings.

Bending radius of the elbow: the bending radius of the central axis of the elbow. In the case where the bending radius of each pipe section of the elbow is inconsistent, the bending radius of the elbow refers to the minimum bending radius among them.

Vertical variation limits: The deflection distance of the pipe in the building or on the surface of the building due to the thickness limitation of the building, the structure of the building and the construction process, etc., in the direction perpendicular to the surface of the building body. , or the roundabout distance, is limited to some extent, and its maximum value is the vertical deflection limit distance. For existing civil buildings, the vertical deflection limit in the wall is generally about 2-8 _cm , and the vertical deflection limit in the floor is usually only l-3 cm. The vertical deflection limit of the pipe laid during the renovation phase is significantly smaller.

Limit line: The limitation of the deflection distance of the building body to the direction of the pipe perpendicular to the surface of the building body constitutes two inner and outer limiting faces, and the limiting faces of the two building bodies connected at an angle are from the surface of the two building bodies. The vertical cross-sections are two L-shaped fold lines inside and outside, and the intersection line of the two inner limiting faces is called a limit line. For pipes buried in building walls and floors, this limit line is what is commonly referred to as a corner line in the case of allowing the pipe to be placed close to the surface of the building.

Maximum bending radius of vertical flat bend: The maximum bending radius of a vertical plane elbow is the maximum bending radius that can be achieved with full use of the vertical deflection limit distance.

Three-dimensional bend: A simple definition is that there is no such plane in which the various parts of the central axis of the elbow are located. The characteristics of the three-dimensional elbow will be further described later.

Pseudo-three-dimensional bend: a three-dimensional elbow formed by two plane elbows whose planes are not parallel. The central axis of the three-dimensional elbow is projected on a plane perpendicular to both planes. It is a polyline formed by connecting two straight segments.

Odd-spot: The bending radius of the cable pipe during bending has an effect on the smoothness of the pipe. In practical engineering applications, the desired bending radius of the elbow is generally about six to ten times the diameter of the pipe. The elbow method provided by the present invention achieves a goal of more than ten times the diameter of the pipe. However, for a bend that uses a bend radius of six times or more the diameter of the pipe, there are inevitably some places where the local bend radius is small, and even the bend radius is zero. Less than the pipe diameter, even where the bending radius is zero, is called a singularity.

Virtual conduit: Due to the inevitable singularities in the actual pipeline, in some cases these singularities have little effect on the passage of the cable. When evaluating the patency of the elbow, the absolute bending radius of the elbow is used as an index to produce a large deviation. In order to get a near-real evaluation, it is necessary to ignore those singularities that have little effect. In order to conveniently measure the actual bending degree of the physical pipeline, a pipeline whose thickness is zero inside the solid pipeline is called a virtual pipeline, and its diameter is less than or equal to the inner diameter of the solid pipeline. Optimum virtual conduit: Within a given physical pipeline, there is one or any virtual pipeline with a maximum bend radius given a feasible virtual pipeline diameter. The virtual pipeline is called the optimal virtual pipeline. The so-called feasible virtual pipe diameter means that the diameter of the pipe should be selected so that at least one virtual pipe can be found inside the solid pipe. On the contrary, when the virtual pipe diameter is too large, it may not be possible to find such a virtual pipe.

Equivalent bending radius: The bending radius of the optimal virtual pipe. When using the equivalent bend radius concept, the minimum diameter of the virtual pipe is usually limited according to the needs of the application.

Virtual-real diameter rate: The ratio of the diameter of the optimal virtual pipe to the inner diameter of the solid pipe. The maximum value is 1, and the minimum is 0. In most engineering applications, the virtual-to-real ratio is preferably between 1/2 and 2/3, that is, the diameter of the optimal virtual pipeline is limited to 1/2 to 2/3 of the inner diameter of the solid pipeline. . In order to simplify the introduction of the technical solution, the virtual-to-real ratio of the optimal virtual pipeline is 1/2 by default unless otherwise specified in this paper.

Equivalent smooth-connecting: This connection is such that the equivalent bend radius of the two pipe segments connected as a single pipe is equal to the smaller of the equivalent bend radii of the two pipe segments.

Accumulative bending angle: For a continuous bend, the cumulative turning angle is the sum of the turning angles of the individual bends along the turning path. For a simple case with only one bend, the cumulative turn angle is the bend angle of that bend.

Extended arc of the plane elbow: The concept of introducing an extended arc is to clearly illustrate the rotation of the pseudo-stereoscopic elbow. For a flat elbow with a turning angle of less than 90°, a circular arc extending from the other end in the same plane is called an extended arc. The circular arc line is tangentially connected to one end of the central axis of the optimal virtual pipeline of the plane elbow, and the plane elbow and the circular arc line are on the same side of the tangent line, and the length of the circular arc line extends just so that the plane elbow and the plane The turning angle of the circular arc as a whole is 90°, and the curved radius of the circular arc is equal to the equivalent bending radius of the planar curved pipe.

Claims

Claim

1 . A method for unblocking a cable duct, characterized in that: laying of the cable duct in the same building surface and turning between different connected building bodies to meet the vertical deflection limit of each building body For the requirements of distance, under the premise of ensuring that the equivalent bending radius of each elbow meets the minimum requirements, select the path and tube combination with smaller cumulative turning angle; select the equivalent bending radius without affecting the cumulative turning angle. Turning path and elbow fittings.

2. The method according to claim 1, wherein: the elbow is used for turning in the same building surface, and the elbow is equivalent to a flat elbow, and the elbow is used for connecting two The steering between the buildings is a three-dimensional elbow or a pseudo-stereo elbow with an equivalent bending radius that satisfies the requirements. The path with a smaller cumulative turning angle for the connected different building bodies refers to the turning point. The three-dimensional elbow or pseudo-stereoscopic elbow applies an effective path after rotating and cutting off the excess pipe segment.

3. The method according to claim 2, wherein: the rotation of the pseudo-stereoscopic elbow refers to the central axis of the optimal virtual pipeline of the two planar elbows holding the pseudo-stereoscopic elbow or its extension arc Simultaneously with the respective planes before the rotation, the two tangent lines are respectively rotated by the rotation axis, and the rotation makes the connection point of the two plane elbows of the pseudo-stereoscopic elbow approach the restriction line of the two connected building bodies.

4. The method according to claim 1, 2, or 3, wherein: the minimum requirement of the equivalent bending radius of the plane elbow, the three-dimensional elbow or the pseudo-stereoscopic elbow refers to a national or industry standard to the bend For the requirement of the minimum bending radius of the tube, the larger equivalent bending radius means not less than 10 times the diameter of the tube.

5. The method according to claim 1, 2, or 3, wherein: the minimum requirement of the equivalent bending radius of the plane elbow, the three-dimensional elbow or the pseudo-stereoscopic elbow is not less than 6 of the diameter of the pipe. In addition, the larger equivalent bending radius means not less than 10 times the diameter of the pipe.

6. The method according to claim 4, wherein: the equivalent bending radius is a bending radius of an optimal virtual pipeline when the virtual-to-real ratio is 1/2.

7. The method according to claim 4, wherein: the equivalent bending radius is a bending radius of an optimal virtual pipeline when the ratio of the virtual to real is 2/3.

8. The method according to claim 5, wherein: the equivalent bending radius is a bending radius of an optimal virtual pipeline when the virtual-to-real ratio is 1/2.

9. The method according to claim 5, wherein: the equivalent bending radius is a bending radius of an optimal virtual pipeline when the ratio of the virtual to real is 2/3.

10. A set of elbow fittings that make the cable conduit clear, including pseudo-stereoscopic elbows, arc-shaped flat elbows and corresponding fittings. The utility model is characterized in that: the pseudo-stereoscopic elbow is composed of an equivalent smooth connection of a plane elbow whose equivalent bending radius is not less than 10 times of the pipe diameter, and the bending radius of the arc-shaped plane elbow and the corresponding pipe joint is not Less than 10 times the diameter of the pipe.

11. The elbow pipe fitting according to claim 10, wherein: the pseudo-stereoscopic elbow is composed of two arc-shaped planar elbows having a bending radius of not less than 10 times the diameter of the pipe, and the equidistant smooth connection is The connection can be a fixed connection or an active connection.

12. The pipe fitting according to claim 10, wherein: the pseudo-stereoscopic elbow and the arc-shaped planar elbow extend at one or both ends of the straight pipe with a small length of the same pipe diameter.

13. The pipe fitting according to claim 10, wherein: the two plane elbows and the arc-shaped plane elbow of the pseudo-stereoscopic elbow have a turning angle of 30° to 45° or 75° to 90 ° .

14. The pipe fitting according to claim 10, wherein: the equivalent bending radius of the pseudo-stereoscopic elbow refers to a bending radius of an optimal virtual pipe when the virtual-to-real ratio is 1/2.

15. The pipe fitting according to claim 10, wherein: the equivalent bending radius of the pseudo-stereoscopic elbow refers to a bending radius of an optimal virtual pipe when the virtual-to-real ratio is 2/3.

16. The pipe fitting according to claim 10, wherein: the pipe joints are respectively formed by tangential connection of an arc segment and a straight pipe, two concentric arc segments or two reverse arc segments.

The elbow pipe fitting according to claim 16, wherein the surface of the annular partition portion (130) in the middle portion of the inner cavity of the pipe joint is arc-shaped.

The elbow pipe fitting according to any one of claims 10 to 15, characterized in that: the inside of the two ends of the pseudo-stereoscopic elbow and the arc-shaped flat elbow are oblique (61) or arc-shaped ports (62).

19. A three-dimensional elbow for unobstructing a cable duct for turning in a direction between different connected building bodies, the turning of which meets the requirements of the vertical deflection limit distance of the building body, characterized by: The tangent to any point on the central axis of the optimal virtual conduit of the three-dimensional elbow is not parallel to the limit line of the two building bodies.

20. The three-dimensional elbow according to claim 19, wherein: the equivalent bending radius of the three-dimensional elbow is not less than 10 times the diameter of the tube.

21. The three-dimensional elbow according to claim 19 or 20, wherein: the three-dimensional elbow is composed of two or more plane elbow equivalent smooth connections.