JPS6123079B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a pressurizing belt for a belt press type sludge dewatering machine. Belt press type sludge dehydrators have become widely used for dewatering sewage sludge, human waste sludge, etc. because of their simple structure and easy operation management. To briefly explain the dewatering mechanism of a belt press type sludge dehydrator, two cloths are usually stretched between multiple rolls, and the cloth is driven by applying a tension of, for example, 5 kg/cm. Sludge is supplied onto the top of the sludge, and gravity dewatering is performed in the first stage, followed by low-pressure dewatering in the second stage by narrowing the gap between two cloths in a wedge shape. In the third stage, by running the cloth in an S shape, the shearing force acting on the sludge promotes dewatering. However, recently there has been a strong desire to reduce the moisture content of the cake as much as possible in order to save energy in transporting and incinerating the cake after dehydration treatment, and it has also begun to be applied to dewatering difficult-to-dewater sludge. Methods are being considered to achieve even higher dehydration. For example, in the final stage of dewatering, a large number of belts are passed in parallel at intervals, and the belts are placed so that they run while pressing the rolls with high pressure, thereby applying high pressure from the outside of the cloth with sludge sandwiched between them. There are methods such as applying water and then promoting dehydration.
According to this method, compared to the conventional method of dewatering only by applying tension to the cloth, the surface pressure applied to the sludge can be further increased, so that the cake dewatering rate can be lowered. The water squeezed out by this belt squeezing comes out from the gap between the belts while it is being pressurized, but in the case of sludge that is difficult to dewater, the amount of water squeezed out is relatively small. Because it takes time for the water in the sludge held down below to move, it is difficult to remove water during the pressurized time, which further lowers the water content. It was becoming a hindrance. In order to improve this point, conventional squeezing means such as rubber belts, which have a structure that does not allow water to pass through without voids, are insufficient to achieve the objective. The present invention takes this point into consideration and provides a pressure belt for further increasing the dehydration effect.The present invention provides a pressure belt in which spiral coils of wire rods are wound in a coil shape are sequentially connected using wire-shaped connecting members to form a sheet. The belt is attached to the final dewatering stage of the dehydrator, pressing against the high pressure roll, and the belt runs while applying high surface pressure using a hydraulic device, etc., and the belt is applied to the fabric between the high pressure roll and the compression spiral belt. The trapped sludge is squeezed out under high pressure. In addition to synthetic resin monofilament yarn, the spiral coil can also be made of yarn coated with a special resin, metal wire, or wire material made of twisted metal wire coated with resin. All coil materials can be used as the connecting member, but it is necessary to select a material with appropriate rigidity and wear resistance depending on the operating conditions of the machine and the properties of the sludge. Further, the dimensions of the spiral coil, the wire diameter of the thread, and the wire diameter of the connecting member can be selected from various values depending on the size of the pressing device, that is, the size of the spiral belt, the strength of the surface pressure to be applied, and the like. In some cases, it is possible to prevent the coil from collapsing due to high surface pressure and to strengthen the coil by inserting an insertion part in the middle of the coil outside the connecting member. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a sludge dewatering device using a pressure belt according to the present invention, which is comprised of two endless cloths 2 and 3, several guide rollers, and a high-pressure belt 1. A
The sludge is supplied onto the lower cloth 3 at a section, and is uniformly dispersed in the width direction and dewatered by gravity, leaving the solid content on the cloth 3 and allowing the water to flow downward, thereby concentrating the sludge.
Next, this sludge layer is sandwiched between the upper cloth 2 and the lower cloth 3 from part B, and as the gap between them decreases, it is pressurized and dehydrated. Further, the cloth is guided successively to groups of shearing and pressing rollers 4 to 6 having different diameters, and dewatering progresses between the cloths 2 and 3. Finally, the sludge moves between the high pressure roller 7 and the back surface of the pressure belt 1, is highly compressed, and is discharged from section E. The final process consists of a high pressure roller 7 and three rollers 11, 12, 13.
A high-pressure belt 1 is wound around three rollers 2 and 13, and by adjusting the roller 11 with a hydraulic cylinder or the like, a desired high tension can be applied to the pressure belt 1. The above-mentioned pressure belt is made by making a linear body into a coil shape 14 as shown in Fig. 2, inserting a connecting member 15 into a common hole created by meshing these, and repeating this process to make a long length. Get the belt. The manufactured spiral belt is heat treated at a temperature of 130°C to 180°C under constant tension to improve dimensional stability. In some cases, the shape of the coil may be adjusted by performing so-called calendering using a heated roller. Both ears of the belt are fixed with resin, or the connecting member is bent inward to secure the connecting member and the spiral coil. The spiral belt made in this way bends freely at the connecting member, so even when it is pressed against a high-pressure roll, it easily follows the curvature of the roll, and the surface pressure applied by the hydraulic device is applied uniformly to the entire width of the cloth. Can be dehydrated efficiently. Example: A spiral coil with a short axis of 4 mm and a long axis of 7.2 mm was made from polyester monofilament thread 0.7 mmφ.
A spiral belt was manufactured using polyester monofilament thread 0.9 mmφ as a connecting member. This spiral belt is placed under a tension of 5 kg/cm, 160
A high-pressure belt was fabricated by heat treatment at ℃, and a dehydration test was conducted on this belt as an example of the present invention together with a comparative example as shown in the table below.

【table】

[Table] As is clear from the results, when the high-pressure spiral belt of the present invention was used, the water content of the sludge was lower than that of the comparative example, and the desired purpose could be achieved. The spiral belt has no obstructed parts,
The pores are large and the water can flow freely, so the water pushed out during squeezing will flow right down without pooling in some areas. Therefore, a highly dehydrated cake with less unevenness in cake moisture content can be obtained. Furthermore, since this belt has a structure in which coils are connected in sequence, it is easy to attach it to a dewatering device to make it endless, and this can be done simply by meshing the loops at both ends and inserting the connecting member by hand. In the same way, remove the connecting member 1.
You can do it just by pulling out the book. Even if a part of the belt is damaged due to an accident or the like, it can be easily repaired by simply removing the connecting members at both ends of the damaged part, removing only the damaged part, and joining a belt of the same size. As described above, the pressure belt of the present invention has the advantage that it can be used in a high-pressure dehydrator without uneven dehydration, provides a high dehydration effect, and is easy to install, so its value is extremely high.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is an example showing a schematic longitudinal sectional view of the entire mechanism of a high-pressure belt press dewatering machine, FIG. 2 is a plan view of a spiral belt, and FIG. 3 is a side view thereof. It is a diagram. 1... Pressure belt, 2... Upper cloth, 3... Lower cloth, 4, 5, 6... Pressing roller 7... High pressure roller, 11, 12, 13... Roller for pressure belt, A-B ... Gravity dehydration process, B-E... Compression shear dehydration process, C-D... High compression process, 14... Spiral coil, 15... Connection member, 16... Insertion member.

Claims (1)

[Scope of Claims] 1. In a belt press type sludge dewatering machine that supplies sludge between two cloths and dewaters the sludge, a wire is inserted into a common hole in which a spiral coil made of wire is meshed. This is a spiral belt for squeezing made into a sheet by connecting connecting members in the order of insertion, and is used in a belt press type sludge dewatering machine that compresses and dewaters sludge by applying high surface pressure from the outside of a cloth with sludge sandwiched in between. pressure belt. 2 The spiral coil and connecting member of the pressure spiral belt are made of a synthetic resin linear body,
2. The pressure belt according to claim 1, wherein the spiral belt is heat-treated under constant tension. 3. The pressure belt according to claims 1 and 2, wherein the synthetic resin linear body is made of polyethylene terephthalate or polybutylene terephthalate resin.