JPH03202319A - Centrifugal molding method of composition pipe having resin concrete layer - Google Patents

Abstract

PURPOSE:To make it possible to efficiently produce a composite pipe, which has resin concrete layer with smooth inner surface by a method wherein resin and aggregate are fed through separate feed routes to a mixing part, which is provided at an arm member, and discharge the mixed resin concrete material through a discharge port. CONSTITUTION:After being fed to a hopper, aggregate is fed by means of a screw blade 32 to a agitatingly mixing part, which is provided on the tip side of a mixing unit 30. Resin material is fed under pressure by means of a compressor through a resin material feed unit 40 and a resin material feed port 36 to the agitatingly mixing part. In the agitatingly mixing part, the aggregate and the resin material are mixed with each other by means of a plurality of pins 34, which are spirally and protrusively provided, and at the same time, fed to the tip position of a material feed arm 30 so as to be ejected by means of resin concrete discharge blade 35 through an exhaust nozzle 37 in the interior of an outer mold for forming pipe.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for centrifugal molding of composite pipes having a resin concrete layer, and in particular, a resin layer is formed on the inner and/or outer circumferential side of the resin concrete layer. This invention relates to a centrifugal molding method that enables efficient production of composite tubes.

[Prior Art] Resin concrete is a piping material that is made of aggregate and resin material and has high strength and excellent corrosion resistance.If a resin layer is formed on the inner and/or outer circumference of the resin concrete layer, Furthermore, corrosion resistance can be improved. When manufacturing a composite pipe having such a resin concrete layer, a centrifugal molding method is generally used. The centrifugal molding method involves rotating the outer mold for tube forming around its axis, pouring the material into the outer mold for tube forming, forming it into a tube shape using centrifugal force, solidifying it, and then releasing the material into the outer mold for tube forming. This method involves taking out the tube from the outer mold, but as described below, it has been pointed out that the productivity is low.

Conventionally, various material supply devices have been used to form the resin concrete layer in the above-mentioned outer mold for pipe forming. , (2) A method is known in which aggregate and resin material are mixed in advance to form a resin concrete material, and this is transported and supplied to the tip of the material supply device. Method (2) is disclosed, for example, in Japanese Patent Publication No. 61-45923, and by this technique, resin layers 2.4 of the same composition are formed on the inner and outer peripheral surfaces of the resin concrete layer 3 as shown in FIG. When manufacturing the formed composite pipe 1, the fifth
The material supply arm shown in the figure is used. That is, from the distal end side of the material supply arm section 50, the first resin material supply section 51. Chopped strand supply section 52. Second resin material supply section 53
．． Sand preparation department 54. A sand supply section 55 is provided.

Therefore, according to the present method, when the material supply arm 50 moves forward, the first resin material 61. The chopped strands 62 are discharged to form the resin layer 2 on the outer peripheral side, and then the second resin material 63. Sand is supplied in the order of sand 64, and when retreating, the sand leveling plate 56 of the sand leveling section 54 is extended as shown in FIG. Then, the first resin material 61 is supplied to form the resin layer 4 on the inner peripheral side.

The purpose of the centrifugal molding method is to form each layer to a uniform thickness using the centrifugal force generated by the rotation of the mold, but as mentioned above, when forming the resin concrete layer, sand and resin materials are separately supplied. In this case, the resin material and aggregate tend to separate due to the difference in specific gravity, making the combined effect of both materials insufficient, and as a result, the aggregate appears on the inner surface of the tube.
As shown in FIG. 5, the inner surface of the tube is not flat but has uneven parts. In order to solve this problem, it is necessary to level the inner surface of the tube using a sand-leveling plate or the like as shown in Fig. 5.6, which greatly reduces productivity.

Furthermore, even if the inner surface of the pipe is smoothed using the sand leveling plate 56, etc., it is difficult to make it a uniform smooth surface, and uneven parts will remain. Therefore, when laminating a resin layer over the entire surface of the concrete layer, The problem is that the amount of expensive resin used is greater than necessary.

JP-A-62-24670 also discloses the method (■).
No. 4 discloses a method of first supplying aggregate and then supplying resin liquid, but this method requires a large centrifugal force of about 50 G to impregnate the resin between the aggregates. At the same time, there are restrictions on the thickness and particle size of the aggregate layer that can be impregnated with resin, and depending on the thickness of the resin concrete layer of the composite pipe to be produced, it is necessary to repeat the steps of supplying aggregate and impregnating with resin several times.

On the other hand, the method (■) is disclosed in Japanese Patent Application Laid-Open No. 64-42207, and in the previous conventional method, resin concrete containing room-temperature curing agent adhered to the mixer or material input device and hardened, so centrifugal molding was required. Focusing on the fact that cleaning work was taking more time, a thermosetting agent was used in place of the room temperature curing agent to prevent the resin concrete material from solidifying at room temperature and to make cleaning easier. However, although this method can prevent the solidification of the resin, it is necessary to solidify the tube inner layer on a centrifugal device and then transfer it to a heating chamber to harden the tube body, which significantly impairs productivity. be.

[Problem B to be solved by the invention] The present invention has been made in view of the above-mentioned circumstances, and it is possible to form a smooth inner surface of a resin concrete layer without using any special sand preparation method, and to improve productivity. The aim is to provide a high quality centrifugal molding method.

[Means for Solving the Problems] The present invention which achieves the above object is to move an arm member of a tube material supply device back and forth in the longitudinal direction of the tube forming outer mold that rotates around the axis, and to achieve the above object. In a method of manufacturing a composite pipe having a resin concrete layer by discharging pipe material from a discharge port provided at the tip of an arm member, resin and aggregate are routed through separate feeding routes to form the resin concrete layer. and feeding the resin concrete material to a mixing section provided at the tip of the arm member, mixing the resin and aggregate in the mixing section, and discharging the mixed resin concrete material from the discharge port to form a resin concrete layer. The main points are as follows.

[Function] The present invention separately feeds aggregate and resin material to the tip of the tube material supply device, and mixes them immediately before feeding them to the outer mold for tube forming to form a fluid resin concrete material. Therefore, the centrifugal force C after discharge can easily spread the material and smooth the inner surface of the tube, so there is no need to use means such as a sand plate to flatten the inner surface of the tube. Moreover, without applying a particularly large centrifugal force, a resin concrete layer in which resin is sufficiently impregnated between aggregates can be formed at once, and production efficiency can be improved. Furthermore, since the structure is such that the mixture is mixed just before the discharge port, most of the material that adheres to various parts of the molding equipment is unmixed material and can be easily removed, so even if room temperature curing agents are used, there is no problem. There isn't. In the end, production time can be shortened without the need for a heating process, and workability during cleaning can be greatly improved since there is no need to clean the material mixer, material feeder, etc. without using a thermosetting agent. becomes.

[Example 1] FIG. 1 is a schematic explanatory diagram showing the state of centrifugal forming of a composite pipe having a resin concrete layer according to the method of the present invention. The rotation mechanism of the tube forming outer mold 14 is the same as the conventional one, and as shown in FIG.
A tube forming outer mold 14 equipped with a forming jig 13 is rotatably placed on the tube forming mold 12 . Also, the trolley 20 is indicated by the arrow XI
The material supply arm 21 is configured to move in the MX2 direction so that it can be inserted into and extracted from the hollow portion of the tube forming outer mold 14.

Although the method of the present invention is not limited by the device used, a typical material supply arm 21 includes a resin material supply section 22, a chopped strand supply section 23, and a chopped strand supply section 23 from the tip side. Some are equipped with a resin concrete supply section 24. Therefore, when supplying material into the outer mold for pipe forming, when the material supply arm 21 moves forward, the chopped strands of resin material and resin concrete are supplied in this order to form an outer peripheral side resin layer and an intermediate layer of resin concrete. However, when retracting, chopped strands and resin material may be supplied to form the inner peripheral side resin layer.

The method of the present invention is characterized in that resin material and aggregate, which were conventionally supplied separately, are mixed and supplied as resin concrete immediately before being supplied to the outer mold for pipe forming. As a specific means for this purpose, a structure in which a mixing unit as described below is installed inside the material supply arm 21 can be exemplified.

FIG. 4 is a schematic explanatory diagram showing a representative example of a mixing unit. A rotating shaft 31 is disposed at the axial center of the cylindrical mixing unit 30 over almost the entire length of the mixing unit 30, and screw blades 32 are formed on the outer peripheral surface of the rotating shaft 31, leaving a portion on the tip side. A hollow rotating shaft 33 is surrounded by a bearing and a sealing material, and the aggregate is fed forward by the rotation of the hollow rotating shaft 33. On the outer peripheral surface of the rotating shaft 31, which is the part where the hollow rotating shaft 33 is not ring-mounted,
A plurality of bins 34 are provided spirally protruding toward the outer circumference,
Furthermore, resin concrete discharge wings 35 made up of a plurality of flat plates are arranged radially on the outer peripheral surface of the tip of the rotary shaft 31.

On the other hand, the resin supply unit 1-4 is located above the mixing unit 30.
0 are arranged side by side, and both units communicate with each other through a resin material supply port 36 bored in the upper part of the outer cylinder, which is located at the boundary between the stirring section of the material supply arm and the aggregate supply section. Furthermore, a resin concrete discharge nozzle 37 is provided at the lower part of the tip side of the mixing unit 30.

Therefore, material supply is carried out as follows. First, the aggregate is supplied to a hopper (not shown), and then is fed by a screw blade 32 to an agitation mixing section disposed at the tip side of the mixing unit 30. The resin material is fed under pressure by a compressor through the resin material supply unit 40 and from the resin material supply port 36 to the stirring and mixing section. In the stirring and mixing section, aggregate and resin material are mixed by a plurality of spirally protruding bottles 34, and at the same time, they are sent to the tip of the material supply arm 30, and are discharged from a discharge nozzle 37 into a pipe by a resin concrete discharge blade 35. It is discharged into the outer mold.

Although the method of the present invention is not limited by the material of the resin concrete layer, for example, a mixture of crushed stone and/or silica sand and an inorganic fine powder filler (silica stone powder, calcium carbonate, etc.) can be used as the aggregate. An example of the resin is an unsaturated polyester resin, and a room temperature curing agent or the like may be added thereto.

Furthermore, in this embodiment, since the rotating shaft 31 and the hollow rotating shaft 33 are controlled by separate variable speed motors, the rotating speed can be changed depending on the particle size and composition of the aggregate, the type of resin material, etc. The materials can be mixed.

Furthermore, normally, the resin material to which a curing agent is added is fed to the resin feeding unit 40, but if a resin feeding unit is used that can feed the resin and the curing agent separately and mix them immediately before stirring, It is possible to further improve productivity, such as by shortening curing time.

[Effects of the Invention] Since the present invention is configured as described above, a centrifugal forming method is provided that can efficiently produce a composite pipe having a resin concrete layer with a smooth inner surface.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram showing a centrifugal molding production device for composite pipes having a resin concrete layer, Fig. 2 is an explanatory diagram in the I direction showing the operating state of Fig. 1, and Fig. 3 has a resin concrete layer. FIG. 4 is a schematic diagram showing a representative example of a resin concrete supply section in the method of the present invention, and FIGS. 5 and 6 are schematic diagrams showing conventional material supply arms. be. 10... Centrifugal molding device 13... Molding jig 14
... Outer mold for tube forming 20 ... Cart 30 ... Material supply arm 40 ... Resin supply unit

Claims (1)

[Claims] The arm member of the tubular material supply device is moved back and forth in the longitudinal direction of the tube forming outer mold that rotates around the axis, and the tubular material is discharged from the discharge port provided at the tip of the arm member to form resin concrete. In a method for manufacturing a composite pipe having layers, when forming a resin concrete layer, resin and aggregate are fed via separate feeding routes to a mixing section provided at the tip of the arm member, and the resin and aggregate in the mixing section, and the mixed resin concrete material is discharged from a discharge port to form a resin concrete layer.