JPH0353119Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a 90° elbow made of synthetic resin.

[Conventional technology]

Generally, when an elbow is formed, the dorsal side (tension side) of the curved part becomes thinner, while the ventral side (compression side) increases in thickness, and in particular, the radius of curvature that forms the curve becomes smaller. Wrinkles, irregularities, and shrinkage occur on the ventral side, and in particular, molded products made by general blow molding tend to wrinkle due to the temperature of the tube material, so this tendency Coupled with this, wrinkles are inevitably formed on the abdomen, and furthermore, the flow inside the elbow is not smooth due to the wrinkles.

In order to avoid such inconveniences, many countermeasures have been taken in the past. For example, Jikko 54-
Publication No. 21765 discloses that in an elbow made by insert molding, the inner circular tube wall, that is, the curved central part of the abdomen, is bulged outward to form a bulge, and the cross section of the center of the bulge is oval-shaped. A proposal has been introduced in which wrinkles and the like are suppressed as much as possible by forming the bulge into a gently curved shape without being subjected to severe compression at the bulge.

However, if the proposed elbow shape is applied to a synthetic resin elbow manufactured by blow molding, the cross section at the center of the bulge is formed into a gentle oval shape. The disadvantage of this mold is that it is expensive to produce, which in turn increases the cost of the product. Another disadvantage is that if various elbows are manufactured with different elbow diameters and straight pipe lengths, it is difficult to determine the dimensions of the bulge.

On the other hand, it is well known that plate stays are used inside mechanical elements that are orthogonally connected and receive external forces (for example, a cylindrical tank and its end plate) to compensate for the lack of strength (see, for example, Japanese Utility Model Application No. 148396/1983). )In Although,
In all conventional plate stays, plate stays are added as reinforcing materials to reinforce the mechanical elements of the main body, so adding plate stays is time-consuming.
Moreover, adding a plate stay to a blow-molded synthetic resin elbow requires the use of adhesive, and the selection of adhesives is limited, so adding a plate stay to the blow-molded synthetic resin elbow requires the use of adhesive. The problem was that it was extremely difficult to add.

[Means for solving problems]

Therefore, the present invention aims to easily design various types of elbows that eliminate the drawbacks of the conventional examples and to provide them at low cost. The gist is that in a synthetic resin 90° elbow formed by blow molding and consisting of a vertical straight pipe part, a curved part, and a horizontal straight pipe part, a vertical pipe is provided on the abdominal side of the curved part. A passage 7 made of the pipe wall itself that short-circuits the horizontal straight pipe part and the horizontal straight pipe part is provided at the same time during elbow blow molding, and the passage 7 is composed of an inclined surface 8 and both side surfaces 9 connected to the inclined surface 8. In addition to forming a triangular plate-shaped space, the width L of the inclined surface 8 is set to 0.4 to 0.5 d relative to the diameter d of the elbow, and the height H is set to be approximately the same as the width L or slightly smaller. The synthetic resin elbow is characterized by:

〔Example〕

The structure of the present invention will be explained in detail based on the embodiments shown in the accompanying drawings. FIG. 1 is a partially cutaway side view of an embodiment of the present invention, and FIG. 2 is a side view taken in the direction of arrow A in FIG.

The synthetic resin elbow 1 of this embodiment is used to catch water from a water storage tank (not shown).
A vertical straight pipe part 2, a curved part 3 curved at a right angle,
A hopper 5 is provided at the upper end of this vertical straight pipe part 2, and a vertical straight pipe part 2 and a horizontal straight pipe part 4 are provided in the abdomen 6 of this curved part 3. A short-circuiting passage 7 formed at the same time as blow molding is provided, and this passage 7 forms a space in the tube. Moreover, this passage 7 has an inclined surface 8,
It is comprised of both side surfaces 9, 9 connected to this inclined surface 8. Therefore, a triangular plate-like space can be formed on the ventral side.

The synthetic resin elbow is molded using a molding method similar to normal blow molding. That is, a heated straight synthetic resin material tube to be formed is pushed into a mold with an elbow shape, and
Pressurized air is blown into this material tube to form the elbow.

In this embodiment, the size of the passage 7 is as follows. The diameter d of the elbow 1 is 165 mmφ, the length l of the vertical straight pipe part 2 is 650 mm, the length m of the horizontal straight pipe part 4 is 270 mm, the radius R of the curved part 3 is 105 mm on the center line of the elbow 1, and the wall thickness t. is 4mm. In this elbow 1, the width L of the passage 7 is 80 mm, the height H is 78 mm, and the center point O of the radius R is located within the passage 7.

By the way, the inventors of the present invention have found, through trial and error, the size of the passageway 7 that can prevent wrinkles in the abdomen 6, etc., and that is easy to manufacture a mold as follows. That is, the width L of the passage 7 is set to 0.4 to 0.5 d relative to the diameter d of the elbow 1, and the height H is set to the width L.
approximately the same as or slightly smaller. Therefore, curved portion 3
It has been found that a passage 7 in which the center point O of the radius R (radius on the elbow center line) is located within the passage 7 is optimal. And the width L of the passage is 0.4d
Below, for example, if the value is 0.3d, wrinkles will occur on the outside of both sides 9, 9 of the passage 7, and the function of forming the passage 7 will not be fulfilled, and if it is 0.6d or more, the wall thickness at the curved portion 3 will be It becomes thinner and problems arise in terms of strength. Further, the height H of the passage 7 is set to be approximately the same as the width L or slightly smaller, but if it is smaller than this, wrinkles will occur in the abdomen 6 of the curved part 3, and if it is larger, the wall thickness will become thinner. was found to be optimal.

[Effect of idea]

According to the present invention, a passage is provided in the abdomen of the curved part of the 90° bend made of synthetic resin by blow molding, which short-circuits the vertical straight pipe part and the horizontal straight pipe part, thereby eliminating the wrinkles that tend to occur during blow molding. This passage not only prevents synergistic wrinkles with the wrinkles that occur on the abdomen, but also provides reinforcement at the curved part, making it ideal for elbows that are relatively thin compared to the diameter (for example,
Even if the wall thickness is 3 to 4 for 180 mmφ,
Its strength can be ensured.

Since the passage is composed of an inclined surface that short-circuits the vertical straight pipe section and the horizontal straight pipe section, and both side surfaces connected to this inclined surface, an enlarged triangular plate-shaped space is formed within the pipe. Originally, vortices are generated in the flow on the ventral side of the curved portion, and the fluid does not flow smoothly, but this expanded space eliminates the vortices and allows the fluid to flow smoothly in the curved portion.

Since the passage is composed of an inclined surface and both side surfaces formed by the tube wall itself, it can be formed at the same time as blow molding, and unlike adding conventional plate stays, it does not require much effort, and it also requires no blow molding metal to form the elbow. Molds can be easily made.

The width L of the inclined surface of the passage is relative to the diameter d of the elbow.
Since the height H is set to 0.4 to 0.5 d, and the height H is approximately the same as or slightly smaller than the width L, it is possible to prevent wrinkles in the curved portion and to provide strength to the thin elbow wall.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of an embodiment of the present invention, and FIG. 2 is a side view taken in the direction of arrow A in FIG. 1... Elbow, 2... Vertical straight pipe part, 3... Curved part, 4... Horizontal straight pipe part, 6... Abdomen, 7... Passage, 8... Inclined surface, 9, 9... Side surface, L...width,
H...Height.

Claims (1)

[Claims for Utility Model Registration] A 90° synthetic resin elbow formed by blow molding and consisting of a vertical straight pipe part, a curved part, and a horizontal straight pipe part, which is perpendicular to the abdominal side of the curved part. A passage 7 made of the tube wall itself that short-circuits the pipe part and the horizontal straight pipe part is provided at the same time during elbow blow molding, and the passage 7 is composed of an inclined surface 8 and both side surfaces 9 connected to the inclined surface 8. to form a triangular plate-shaped space, and the width L of the inclined surface 8 is set to 0.4 to 0.5 d relative to the diameter d of the elbow,
A synthetic resin elbow characterized in that the height H is approximately the same as the width L or slightly smaller.