JPS6014242B2 - Steam generator tube support structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat exchangers, and more particularly to tube/shell type steam generators.

Tube/shell type steam generators used in nuclear power plants are
It comprises a container (shell) and a number of stainless steel tubes arranged inside the container with both ends fixed to tube sheets.

The tubes are usually arranged in an equilateral triangular array and are supported by support structures at several points along their length. The support structure of the steam generator is
Hold each tube firmly to suppress vibration and provide as little resistance to fluid flow around the tube as possible;
In addition, it is necessary to minimize the formation of gaps around the tube in which impurities and the like can easily accumulate. Conventional tube support structures lack one or more of the above conditions. For example, an orifice-type support plate has a high resistance to fluid flow and also creates a large number of gaps around the tube. If impurities are deposited between the tube and the support plate, the tube will be "eaten" by the support plate or the impurity. A tube support structure consisting of a plate with froached holes also suffers from the above-mentioned "digging" phenomenon, although to a lesser extent than the orifice plate.

This tube support structure also has very high manufacturing and transportation costs. Other tube support structures, such as those that hold bars between rows of tubes, tend to induce fluid flow vibrations and therefore damage the tubes. The present invention overcomes the drawbacks of the prior art discussed above and provides a unique "egg-holding frame" type tube support structure that provides low flow resistance, increased strength, and reduced manufacturing costs. In an equilateral triangular tube arrangement, such as in a steam generator, each tube is equidistant from the six tubes around it;
It is a member of three distinct rows of tubes extending in three directions at 60° angles to each other.

According to the invention, three groups of grid strips are provided, each group of grid strips extending between each tube along a corresponding one of the three extension directions. In one embodiment, the first group of grid strips are "full height width" and extend between the tubes in the first direction, and the second and third groups of grid strips are "r part height width"; The tubes extend in a second direction and a third direction, respectively, through the tubes.

Here, the term "full height and width" lattice strip refers to a lattice strip that is larger in height and width than the lattice strips in other groups, and the term "partial height and width 1 strip" refers to a lattice strip that is wider than the full height and width 1 strip. A narrow strip.The upper and lower edges of a full-height and width strip have a plurality of slots for receiving part-height and width strips. Each strip is provided with a dimple which contacts the tube wall of the steam generator.

The tube support structure of the present invention provides many advantages as described below. The 'i' structure is simple and reduces manufacturing time.

'. 'Reducing the pressure drop of the fluid through this tubing structure,
Therefore, the required pumping power can be reduced. Shiichi
Reduce transport weight.

0 Reduces vibrations in pipes and steam generators.

[vs.] The maneuverability of the lattice-like body is large, thus increasing the maneuverability of the tube, thereby suppressing the occurrence of the above-mentioned "digging" phenomenon. N Open grid configuration provides good steam flow conditions and good flow distribution in the upper part of the steam generator.

This tube support structure does not grip the tube tightly, allowing the tube to slip to absorb the hot air.

It is an object of the present invention to provide a steam generator tube support structure that provides flexible contact support to suppress vibration.

Another object of the present invention is to provide a support structure that has the above-mentioned advantages and is less prone to "digging". Another object of the invention is to provide a support structure that has the above advantages and is easy to manufacture and transport.

Yet another object of the invention is to provide a support structure having the above advantages and having low resistance to fluid flow.

Referring to FIG. 1, a steam generator tube support structure 10 is shown in accordance with a preferred embodiment of the present invention.

The structure 1 has two types of lattice strips 12, 22 arranged in three strip groups 12, 22a, 22b. Details of the two types of strips 12 and 22 will be described later.

Each strip group 12, 22a, 22b is oriented at an angle of 60 degrees with respect to the other two groups. Viewed from above, this arrangement forms an equilateral triangular array as shown in FIG. 7, defining a hexagonal tube-receiving compartment surrounding each tube. As seen in FIG. 1, the strip 12 is a full width strip having a plurality of longitudinally spaced strip receiving slots formed in both its upper and lower edges.

The strips 22a and 22b have the same structure and are both strips with a partial height and width, and slots are formed only at the upper green and lower edges, respectively.To explain with reference to FIG. Slots 14 and 16 are cut out alternately in the upper and lower greens 13 and 15 of the piece 12, respectively.

This staggered alignment is important in defining the hexagonal tube-receiving compartments described above. When the upper and lower slots are aligned vertically, rather than staggered, a triangular tube-receiving compartment is defined. Strip 12 also has a plurality of dimples 18 formed therein, with depressions 20 defined on the back side of the dimples. FIG. 3 is an elevational view of the partial height width strip 22. The strip 22 has a slot 24 cut in only one green side thereof. Dimples 18 are also formed on the strip 22. When strip 22 is aligned with strip 12 through slots 24 and 14, green 2
5 and 13 are located in approximately the same horizontal plane. When strip 22 is assembled with strip 12 through slots 24 and 16, edges 25 and 15 lie substantially in the same plane. Referring to FIG. 4, a modified embodiment of a partial height width strip is shown.

The strip 23 of this embodiment differs from the strip 22 of FIG. 3 in that a rectangular dimple 19 is formed. A depression 21 is defined behind the dimple 19. FIG. 5 shows the angle 600 of the slot 24 with respect to the plane of the strip 23.

Slots 16, 14 in strip 12 and slot 24 in strip 22 are also angled at 60 degrees. As can be seen in FIG. 5, the dimples 19 (as well as the dimples 18) project away from the 600 angle that the adjacent slots 24 (or 14, 16) make with the plane of the strip. In other words, the recess 21 (or 20) always faces within the corresponding 60o corner. Applying this to the strip 12 in FIG. 2, the slots 14 and 16 are not cut parallel to each other in the same direction, but are oriented at an angle of 60 degrees to each other (and to the strip). There is. This orientation is required to form a hexagonal tube receiving compartment. Another feature of the embodiment shown in FIGS. 2-5 is the special arrangement of dimples 18, 19.

That is, if the edges 13, 15 of the strip 12 shown in FIG. 2 lie on a horizontal plane, the dimples 18 are arranged to define four additional horizontal planes A, B, C, and 0. Similarly, the dimples 18 of the strip 22 in FIG.
be placed so as to define When strip 22 is combined with strip 12 to form the assembly of FIGS. 1 and 6, strip 22
The planes E and F of the strip 22b are coextensive with the planes B and A of the strip 12, respectively, and the planes E and F of the strip 22b are coextensive with the planes C and D of the strip 12, respectively.

Each hexagonal compartment 28 will therefore have eight dimples 18 projecting therein. If desired, the strips can be combined so that opposing dimples 18 within each compartment 28 lie in the same horizontal plane.

As shown in FIG. 6, the strip 22a is the green 1 of the strip 12.
3 by welding 26.

Similarly, strip 22b is secured to edge 15 of strip 12 by welding (not shown). Also, as seen in FIG. 6, triangular compartments 29 are defined between each hexagonal compartment 28. These compartments 29 are open to allow free flow of fluid. Referring to FIG. 11, a partial horizontal cross-sectional view of a tube/shell heat exchanger having a shell or enclosure 34 is shown.

Hexagonal support structure 1 mentioned above, ring 3 detailed below
It is surrounded by 6. The keyway iron fitting protrusion 38 and the wedge 44 are fitted into the shell body 34 and supported. FIG. 7 shows the relationship between the ring 36 and the shell 34.

The keyway 40 formed in the ring 36 is connected to the keyway iron fitting protrusion 3
8 and aligns and fixes the ring 36 to the shell 34 at a predetermined angular position in the circumferential direction. Lug 38 is secured to shell 34 by welding 42 or other suitable means. Tapered surface 46 of ring 36 is configured to cooperate with wedge 44 as described below.

As shown in FIG. 8, the support structure 10 includes a ring 3
6 and fixed by welding or other appropriate means. FIG. 9 shows a plan view of a portion of wedge 44. FIG.

Wedge 44 is secured to shell 34 by welding or other suitable means. FIG. 10 shows the relationship between the wedge 44 and the ring 36. The tapered surface 46 of the ring 36 is
It is joined to wedge 44 and secured thereto by welding or other suitable means. Wedge 44 tapers downwardly to restrain upward movement of ring 36. This arrangement is made in view of the fact that the net force exerted on ring 36 by upward fluid flow on the shell side (i.e., outside the tubes) of the heat exchanger (steam generator) is in an upward direction. Referring to FIG. 11, the heat exchanger is provided with a worker passageway 60 through which a worker passes during assembly work of the heat exchanger.

It is fixed to the lattice structure 10 with five-way bolts 54. Referring to FIG. 13, structure 10' has a nut 52 attached thereto, and passageway 50 has a bushing 56 aligned therewith. Bolts 54 and bushings 56 are threaded into suitable nuts 52, thereby securing passageway 50 to structure 10. FIG. 12 shows a tube support structure 70 according to another embodiment of the invention.

Full height and width strips 62 are located in a first direction, and partial height and width strips 72a and 72b are located in a second and third direction, respectively. Each direction is 60% from the other two directions.
o It is deflected. This arrangement is the same as that in FIG. The difference in this embodiment is that the strips 72a and 72b are cross-engaged in the slot 64. This overlapping configuration provides additional stiffness and strength laterally to the structure 70'. Such an overlap may extend over the entire width of the strips 72a, 72b. In that case, the height and width of the strips 72a and 72b are made the same as that of the strip 62. Although the present invention has been described above in connection with embodiments, the present invention is not limited to the structure and form of the embodiments illustrated herein, and may be modified in various ways without departing from the spirit and scope of the present invention. It will be apparent to those skilled in the art that many different embodiments are possible and that various changes and modifications can be made.

[Brief explanation of the drawing]

1 is a partial perspective view of a preferred embodiment of a tube support structure according to the invention; FIG. 2 is a partial elevation view of a full height width strip of the structure of FIG. 1; and FIG. 3 is a partial height width strip. Partial elevational view of the strip, FIG. 4 is a partial elevational view of the strip showing the deformation of the dimples, FIG.
1, FIG. 6 is a plan view of the tube support structure of the present invention, and FIG. 7 is a partial plan view of the structure shown in FIG. 6, showing angular position alignment means. , FIG. 8 is a partial elevational view taken along the line of FIG. 7, FIG. 9 is a partial plan view of the structure shown in FIG. FIG. 11 is a partial horizontal sectional view of a heat exchanger using a preferred embodiment of the invention; FIG. 12 is a partial perspective view of an alternative embodiment; FIG. , FIG. 13 is a partially exploded elevational view of the worker passageway. 12, 22a, 22b: strip, 13, 15, 25: edge of strip, 14, 16, 24: slot, 18, 19: dimple, 34: shell, 36: ring, 37: notch, 3
8: Key groove joint protrusion piece, 40: Key groove, 44: Wedge,
50: Worker passage, 52: Natsu, 54: Bolt, 56
:Butshu. -FIG. 8 FIG. l F! G2 [IG. 3 FIG. 4 [IG. 5 FIG. 6 Fig. 7 FIG. 9 FIG. 10 rIG. 11 FIG. 12 FIG13

Claims (1)

Claims: 1. A tube support structure for supporting an array of tubes arranged parallel to each other in the shape of an equilateral triangle, each in a first direction substantially perpendicular to said tubes; a plurality of mutually parallel first strips extending between a corresponding pair of tube rows of the body, each in a second direction substantially perpendicular to the tubes, and each extending between a corresponding pair of tube rows of the array; a plurality of mutually parallel second strips extending between the rows of tubes;
a plurality of mutually parallel third strips extending in a third direction substantially perpendicular to the tubes and each between a corresponding pair of tube rows of the array; The second direction and the third direction are each deflected by approximately 60° from the other two directions, each first strip has a plurality of slots formed on both edges thereof, and each second strip has a plurality of slots formed on both edges thereof. The first strip and the third strip have a plurality of slots formed on one edge thereof;
One edge of the plurality of first strips is engaged with and fixed to the plurality of second strips through the slot, and the other edge of the plurality of first strips is engaged with and fixed to the plurality of third strips through the slot. The first strip and the second strip are thereby engaged and fixed through the first strip and the second strip.
the strip and the third strip are arranged to define a plurality of hexagonal tube-receiving compartments each surrounding a tube, the first, second and third strips having: A tube support structure comprising a plurality of dimples contacting each corresponding tube within each tube receiving compartment. 2. The tube support structure of claim 1, wherein at least one of the dimples is circular. 3. The tube support structure of claim 1, wherein at least one of said dimples is rectangular. 4. A tube support structure as claimed in claim 1, wherein each one of said tubes is provided with at least eight dimples. 5. A tube support structure according to claim 1, wherein each of said slots is formed at an angle corresponding to a direction in which said strip engages a corresponding strip. 6 one edge of each said first strip is substantially coplanar with one edge of each second strip, and the other edge of each first strip is substantially coplanar with one edge of each third strip; 6. A tube support structure as claimed in claim 5 in the same plane. 7 The plurality of first strips are connected to the plurality of second strips and the third strip.
7. A tube support structure according to claim 6, wherein the tube support structure is secured to the strip at said respective coplanar edges by welding.