JPS6039426B2 - centrifugal dehydrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a centrifugal dehydrator used for purposes such as dehydration of sewage in water treatment facilities.

A conventional horizontal centrifugal dewatering machine has a cylindrical casing with a tapered part formed in the front half with a narrow front end and a large diameter rear end, and a casing arranged concentrically with a slight gap inside this casing, which is almost the same shape. The casing and screw are rotated at high speed with a slight speed difference, and the sewage that flows in from the center of the rear of the screw is transferred to the large side of the tapered part of the screw. The solids flowed outside and separated by the far-D force are discharged from the solids outlet at the front end of the casing by the feeding action of the screw, and the separated desorbed liquid is discharged from the desorbed water outlet formed at the rear end of the casing. This is how it was done. However, upon careful consideration of this type of dehydrator, there are problems with the dehydration effect on solid materials. In order to make this problem easier to understand, we will remove the centrifugal action and replace it with a device that separates solids by gravity sedimentation, as shown in Figure 1. In FIG. 1, reference numeral 1 denotes a separation tank, and the first half of its bottom is a sloped part 2 with a high front part, and a flat part 3 in the second half. Also, a scraper 5 is attached to the endless chain 4.
A solid material scraper C, which is attached at regular intervals, is arranged along the inclined part 2 and the flat part 3, and the settled solid material 6 is discharged from the solid material outlet 8 at the front of the tank 1, and the desorbed water 7 is It is designed to be discharged from the desorbed water outlet 9 at the rear. In this case, the problem is that once the thickest solids have settled on the flat surface 3, they move in the direction of the arrow. This means that the rate will increase. As a solution to this problem, a solid matter drawing pipe 12 is provided at the bottom of the tank 11 as shown in FIG. If the solids are discharged from the tank, the moisture content of the solids will not increase. However, the centrifugal dehydrator mentioned above is the first
This corresponds to a system in which the separation tank 1 shown in the figure is a rotating body with the horizontal line in the longitudinal direction as an axis, and the scraper C is a screw. In view of these problems, the present invention applies the device shown in FIG. 2 to a centrifugal dehydrator, and the details thereof will be explained as follows. In the figure, 21 is the horizontal axis,
A is a casing of the same type D that is installed on the outside of the horizontal shaft 21 so as to be freely rotatable, and the rear end portion 22 has a diameter of 4 mm and is rotatably fitted on the outside of the shaft 21.

Further, the small-diameter front end portion 23 is rotatably fitted to the outside of the shaft 21, and the central portion 24 has a large diameter, and the front and rear portions thereof are substantially tapered. B is a screw that is placed in the front half of the casing A and whose front end is fixed to the shaft 21, and is a hollow screw with an approximately tapered shape and an open rear end that runs along the inner surface of the front half of the casing A with an appropriate gap. It consists of a main body 25 and a plurality of spiral blades 26 formed on the outside thereof. As shown in Fig. 4, this blade 26 is spirally formed from the front end toward the rear in the direction of arrow a indicating the rotation direction of screw B, and casing A rotates in the same direction as screw B with a slight delay. As a result, the solid matter 30 on the inner surface of the casing A is scraped toward the center, that is, toward the front of the screw B by a component force as indicated by the arrow in FIG. Further, a desorbed water outlet 27 is formed in a portion near the rear end portion 22 of the casing A, and a solid matter outlet 28 is formed in the front end portion 23. Further, the shaft 21 is hollow with a closed front end, and a sewage supply pipe (not shown) is connected to the rear end via a rotating pocket, and a sewage outlet 29 is formed inside the screw B at the front of the shaft 21. The present invention has the above-mentioned configuration, and while driving the casing A and the screw WB in the direction of the arrow in FIG. 4 with a slight speed difference using an appropriate drive mechanism, the shaft 21
Sewage is supplied into the screw B and discharged into the screw B through the outlet 29.

This waste water flows backward along the inner surface of the main body 25 of the screw B while swirling, and due to centrifugal force, the solids 3 flow along the inner surface of the central part 24 of the casing A, and the desorbed water 31 is discharged from the desorbed water outlet 27. be done. The solids 301 along the inner surface of the central portion 24 are moved along the front half surface of the casing A by the blades 26, and are discharged from the solids outlet. Note that the rotation of the casing A and the screw B is varied depending on the speed at which the solid material is pulled out by the screw B.

That is, as for the drawing speed of the solid material, the exit speed C2 is higher than the inlet speed C. In other words, the shape of the screw B is calculated so that C4-C2>0. Just when the volute pump is in reverse rotation, the inlet and outlet angles of the vanes 26 become the center side and the outer side of the pump, the incident angle and the outlet angle, and in this screw, the outer side and the center side are opposite. Therefore. Hth
Plate (U-tei-Hoju (C-tei-C room) Ju (Wu Kiichi V-kyo))
>○, that is, u≧-u wife>0, so a design curve such that C≧-C poison+W≧-V hawk>u-tei-u-room is required.

In the present invention, by making the casing A and the screw IJ B into special shapes as described above, solids separated by centrifugal force can be discharged without passing through water.

In other words, the sedimentation method shown in Figure 2 has been applied to the centrifugal method, and the wastewater passes through the hollow machine shaft and enters the main body from the wastewater outlet that opens at the smallest diameter part at the front inside of the main body. Therefore, the waste water is subjected to sufficient centrifugal separation over the entire length of the main body. Therefore, it has the feature of providing a much better dehydration effect than conventional centrifugal dehydrators.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional side views showing examples of sedimentation type separation tanks, FIG. 3 is a longitudinal sectional side view of the centrifugal dehydrator of the present invention, and FIG. 4 is a front view of the same. A...Casing, B...Screw, 21...Horizontal shaft, 22...
Rear end, 23...front end, 24...center, 25...main body, 26...blade, 27...separated water outlet, 28...
Solids outlet, 29...sewage outlet. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A casing that can be rotated at high speed around a horizontal axis,
It consists of a screw that is concentric with the casing and rotates in the same direction as the casing with a slight speed difference within the casing. The part has a large diameter,
In addition, a desorbed water outlet is provided at the rear end, and a solid matter outlet is provided at the front end, and the screw has an approximately tapered hollow main body with an open rear end that runs along the inner surface of the first half of the casing with an appropriate gap, and a hollow main body with an open rear end. , a plurality of spiral blades are formed from the front end toward the rear and are oriented to scrape out solid matter accumulated between the inner surface of the first half of the casing and the outer surface of the main body to the solid matter outlet of the casing, and the horizontal shaft is located at the front end. A centrifugal dehydrator characterized in that the rear end is closed and hollow, the rear end is connected to a waste water supply pipe via a rotary joint, and the front part is provided with a waste water outlet that opens at the front inside of the main body of the screw.