JP3474733B2 - Storage and discharge device for dewatered sludge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage and discharge device for storing dehydrated sludge dehydrated by a dehydrator, continuously performing quantitative cut-out, and supplying it to the next step.

[0002]

2. Description of the Related Art Sewage sludge storage is extremely difficult due to variability of sludge properties and bridge phenomenon, and in such circumstances, it has been handled by a multi-screw or cut gate method. Recently, a storage tank (conical silo) provided with a sludge scraping section has become the mainstream as a device for a temporary sludge storage facility.

The conventional sludge scraping section is provided at the bottom of a truncated cone-shaped storage tank for storing dewatered sludge, and the rotor arm for discharging is rotated in a horizontal plane to stir the sludge. It is a device that discharges while. Such an apparatus is shown in FIGS. 8 and 9 (see Japanese Patent Publication No. 61-16701).

Referring to the drawings, the sludge scraping section
(29) has a hollow disk shape and is attached to each of the rotor (30) fixed to the reduction gear shaft (24) and rotatable and the two crankshafts (31) provided inside the rotor (30). And a spring arm (32) protruding to the lower surface.

The crankshaft (31) includes a hydraulic cylinder (34) and a shaft (3) which are axially supported in the rotor (30) inside the rotor (30).
The two crankshafts (31) are rotatable independently of each other. And crankshaft (3
Since the rotation center (31a) of 1) is eccentric from the center of the rotor (30), the distance between the tip of the spring arm (32) and the center of the rotor (30) is shown by the operation of the hydraulic cylinder (34). Can be changed like. That is, the spring arm (3
2) expands and contracts with respect to the rotor (30). The leaf spring portion (35) at the tip of the spring arm (32) is replaceably fixed by a pin (36).

The rotation speed of the rotor (30) is controlled by the hydraulic motor (21) self-controlling according to the load due to changes in the amount of dewatered sludge stored, water content, properties, etc. 4.2 rpm). Then, the expansion and contraction operation of the spring arm (32) is performed by measuring the sludge load received by the spring arm (32), for example, by measuring the number of rotations of the rotor (30) by the rotation speed detector (25) attached to the speed reducer shaft (24). If this is done (it can be done by measuring the amount of torque), and if the rotational speed falls below the set lower limit rotation speed, the hydraulic cylinder (34) is driven to completely retract the two spring arms (32) and reduce the rotor load. After that, when the rotation speed of the rotor (30) reaches or exceeds the set upper limit rotation speed, the spring arm (32) is pulled out again.

[0007]

Recently, there is a trend toward larger-sized sludge storage facilities due to the integration of sludge treatment over a wide area.
In addition, the technology of sludge dewatering machines has advanced to reduce the water content of dewatered sludge, and the load resistance acting on the rotor arm is increasing. However, in the conventional sludge scraping unit, a hydraulic cylinder and a pipe for moving the arm unit are installed in the rotor unit. Therefore, the rotor portion is very large, and the rotational load resistance acting on the rotor portion becomes large. Therefore, the hydraulic motor and the speed reducer used for rotationally driving must be necessarily large. Since the hydraulic motor and speed reducer capacity is also limited, the amount of dewaterable sludge that can be stored is limited. Further, since the internal mechanism of the rotor section is complicated, there are many problems such as oil leakage from hydraulic piping.

It is an object of the present invention to provide a storage and discharge device capable of maintaining a safe and reliable sludge discharge capacity in a large-capacity storage sludge facility that can cope with such problems.

[0009]

The invention according to claim 1 for solving the above-mentioned problems, is a truncated cone-shaped storage tank for storing dehydrated sludge, a scraping portion for scraping the dehydrated sludge, and the storage. A storage and discharge device for dehydrated sludge, comprising: a sludge discharge port provided at the bottom of a tank; and a cutout section for cutting out sludge from the sludge discharge port, wherein the scraping section is the center of the bottom of the storage tank. a drive shaft projecting from the, Ri Do and a rotary blade which is fixed to the upper end of the drive shaft scrape the dewatered sludge, and characterized that no such has a rotor portion. Here, it is preferable that the rotary blade is a flat plate having a thickness d arranged in parallel with the bottom portion and having a tapered shape in which the width 1 becomes smaller toward the tip of the blade (claim 2).

From the experience of the inventors and the results of experiments and the like, in the conventional machine, the load resistance due to the frictional force generated between the dehydrated sludge and the contact surface of the rotor portion affects the torque required for rotation and becomes large. It turned out. Moreover, the movable mechanism of the arm part at the time of rotation start adopted in the conventional machine is used to reduce the load resistance applied at the time of start, but the load resistance applied at the time of actual start is during rotation (during operation). It was also found to be smaller than this maximum load resistance. Therefore, it is considered that the arm does not need to have a telescopic movement function.

The present invention has been completed based on the knowledge that the rotor section can be eliminated and the arm section can be replaced by the rotary blade. If the thickness of the rotating blades is increased, the strength will be improved and the bridging phenomenon can be avoided, but the load resistance for rotation will increase and the driving force will be reduced. The same as the sludge scraping part with the rotor part of the conventional machine. In the sludge scraping section that has no rotor section and has rotating blades, the load on rotation is reduced,
It is possible to achieve downsizing of the driving device (reduction of driving force).

[0012]

[0013]

The scraping part is provided at the bottom of the storage tank.
The drive shaft protruding in the center and the dehydration fixed to the drive shaft
It is preferable that a rotary vane for scraping sludge is provided, and a circular guide rail that supports the lower side of the rotary vane is provided on the bottom portion (claim 3 ). In this case, the range of the radius r'from the center of the installation position of the guide rail is 0.
More preferably, 55 × r ≦ r ′ ≦ 0.85 × r (where r is the radius of the rotating blade, unit mm) (claim 4 ). Furthermore,
It is further preferable that a replaceable sliding member is attached to the rotary blade facing the guide rail (claim)
5 ).

When the arm passes through the upper part of the sludge discharge port provided in the bottom part, the vertical vibration / fluctuation of the arm is very large, and this phenomenon is particularly remarkable in the lime type sludge property. Unless the blades are externally restrained, the rotating blades fluctuate, which is a cause of fatigue failure. It is necessary to externally restrain the vertical movement of the rotary vanes above the sludge discharge port. Therefore, the guide rail is effective.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a dehydration sludge storage and discharge device of the present invention.

The storage / discharge device 1 functions as a dewatered sludge quantitative supply tank, and is mainly a storage tank 2 formed in a truncated cone shape.
And the scraping part 4 provided on the bottom part 3 and the bottom part 3
And a screw 5 as a sludge cut-out portion. Here, the sludge scraping section 4 is characterized in that it comprises a rotary blade 7 fixed to the upper end of the drive shaft 6.

The dehydrated sludge discharged from the dehydration equipment, etc.
It is received from the upper part of the storage tank 2 by a sludge transfer device (not shown). The stored dewatered sludge 8 is collected by the scraping section 4 into the screw 5 as a sludge cutting section provided in the lower portion through the sludge discharge port 3a, and is quantitatively conveyed to the next facility by the screw 5.

Rotating blades 7 constituting the sludge scraping section 4
The detailed shape of is shown in FIG. 2A is a sectional view, FIG.
2B is a top view, and FIG. 2C is a sectional view of the rotary blade 7. By linearly narrowing the width 1 of the blade from the center, which is the connecting portion with the drive shaft 6, to the tip, the maximum stress is made uniform, that is, equal strength is secured in any radial cross section. Also, by eliminating the central rotor as in conventional machines, the required driving force is reduced.

That is, the rotary blade 7 is driven by cutting a flat plate of thickness d into a rhombus, opening a mounting hole at the center O1, fitting the mounting hole portion to the upper end of the drive shaft 6, and fixing it with bolts. It has a simple shape provided integrally with the shaft 6. Further, the tip of the rotary blade 7 extends to the vicinity of the outer periphery of the bottom portion 3 of the storage tank 2, and the gap between the bottom and the bottom portion 3 is 40.
It is about mm. Further, a chamfer 15 of C = 5 to 20 mm is provided on the upper side of the front edge in the rotation direction of the rotary blade. In addition,
The drive shaft 6 is a speed reducer 1 attached to the center of the base of the bottom portion 3.
3 is an output shaft, and the speed reducer 13 is rotationally driven by a hydraulic motor 14.

A guide rail 11 concentrically arranged on the center O1 is attached to the bottom portion 3 of the storage tank 2, and an auxiliary plate 12 as a sliding member is attached by bolts or the like to a portion of the rotary blade 7 that abuts on the guide rail 11. It is replaceably attached.

[0022]

EXAMPLES The performance of the sludge scraping part according to the present invention was confirmed by experiments using lime-based sludge. FIG. 3 shows the measured values of the torque of the rotary blades. Since the torque generated in the sludge scraping unit according to the present invention has a structure in which the rotor unit is eliminated, it is about 2/3 of the torque generated by the conventional machine, and the drive device can be downsized. Further, since the pulse load generated at the time of start-up is less than the maximum torque during operation, there is no problem in the shape without the rotor.

FIG. 4 shows the relationship between the rotary blade thickness and the torque / discharge capacity. When the blade thickness d is smaller than 45 × D / H (D: hopper bottom diameter, H: hopper height), the discharge capacity sharply decreases. If the width of the blade is increased, the discharge capacity is increased, but the load due to the friction between the blade surface and the sludge is increased. Further, when the blade thickness d is larger than 100 × D / H, the rotational pushing load sharply increases. If the blade width is reduced, the frictional force will be eliminated, but the strength will become uncertain and the discharge capacity will decrease extremely. By determining the blade thickness and width within the design conditions, it is possible to obtain an optimally-shaped rotating blade that can suppress the torque and fully exhibit the discharge capacity.

FIG. 5 shows the relationship between the chamfering amount and the vertical load in the chamfered shape attached to the front edge of the blade as shown in FIG. When an upward vertical load is applied to the rotating blade, the blade is deformed such that it is banzai, and unless the load state changes, it causes breakage or the like unless the blade is externally controlled. Therefore, the vertical load applied to the rotary vanes needs to be 0 or less if the upward direction is positive. It can be seen that, when the blade is not chamfered, the load is applied vertically upwards on average, whereas the chamfering at the position shown in FIG. 2 causes the vertical load direction to change downward.

However, if the chamfering amount is less than 5 mm, the pressing force of the sludge against the rotary blades becomes insufficient, and the vertical load on the blades becomes upward. If the chamfering amount exceeds 20 mm, the pressing force will be unnecessarily large and the blades will be deformed downward, which may be unpredictable such as twisting depending on how the force is applied. In addition, the blade leading edge strength may be insufficient and scratches may occur, which may cause breakage or the like. From these results, and taking into consideration the difference in the amount of fluctuation due to the characteristics of sludge, etc., the vertical load applied to the rotary blades is selected to be 0 or slightly downward on average in the range of 5 to 20 mm.

FIG. 6 shows the relationship between the shape of the rotary blade and the torque. By chamfering, the torque can be reduced by about 10% compared with the blade-shaped torque without chamfering.

When there is a guide rail attached to the bottom and an auxiliary plate as a sliding member attached to the rotary blade as shown in FIG. 2, the gap between the rotary blades at the guide rail mounting position and the maximum stress applied to the rotary blade The relationship is shown in FIG.

(A) shows that the guide rail does not contact the bottom of the hopper even when the blade is deformed downward, and the guide rail is provided at the bottom with a length of about 0.3 times the blade radius from the blade tip so that the maximum stress is suppressed. It is the result when it was installed on the circumference that entered inside. The maximum stress that can be controlled increases as the clearance is increased, but by controlling the clearance between the rotary blade and the guide rail within 10 mm, the maximum stress can be increased.
It can be suppressed within 13kg / mm ² . For the material of the rotary blade
When SS400 is used, the yield point is 22 kg / mm ² , there is a considerable margin in static strength, and there is a margin in fatigue strength as well, so there is no fear of breakage.

(B) is about 0.15 of the blade radius from the blade tip.
It is the result when it is installed on the circumference that is inside by double the length (shifted to the outside of the installation position in (a)). The stress until the rotary vanes are supported by the rail can be reduced compared to the case of (a), but the stress increment due to the load after being supported by the rail is large, and as a result the maximum stress is at the position of (a). It will be bigger than when. There is a margin in static strength, but there is little margin considering fatigue strength. Further, when the rail is installed inside (a), the stress increment until the rail is supported is very large, and the tip of the rotary blade may rotate while contacting the bottom, which is not preferable.

Therefore, at a position (0.55r ≦ r ′ ≦ 0.85r) based on the analysis result in (a), a guide rail having a height such that the clearance between the rotary blade and the guide rail can be controlled to 10 mm or less is provided. Install.

Further, in consideration of damage caused by the contact between the rotary blade and the guide rail, an auxiliary plate is installed on the rotary blade side where the contact between the rotary blade and the guide rail is assumed. SS40
By using an auxiliary plate made of a material equivalent to 0, the rotary vanes and the guide rails will not be worn or damaged due to contact, and safe and complete discharge of sludge can be performed. The worn-down auxiliary plate can be easily replaced at the time of regular inspection.

[0032]

As described above, according to the first and second aspects of the present invention, the scraping portion has a rotary blade structure, the R portion of the rotary blade is minimized, and the blade gradually becomes closer to the tip of the blade. Since the shape is becoming thinner, the rotor eliminates the load resistance due to the frictional force with the sludge, which significantly reduces the driving force required for rotation by about 30%. Further, the stress distribution becomes uniform by narrowing the width of the rotary blade toward the tip. As a result, the strength of the blade is increased and the blade thickness can be reduced.

[0033]

According to the invention of claims 3 , 4 and 5 , wherein the bottom portion is provided with a circular guide rail that supports the lower side of the rotary blade, the downward variation of the rotary blade is 10 at the bottom of the silo.
It can be suppressed to mm or less. As a result, the amount of displacement of the rotary blade due to the load resistance can be controlled within a fixed range, so that breakage due to a sudden increase in load resistance can be prevented. At the same time, since the same orbit is advanced, the discharge capacity can be made uniform. Further, since it is not necessary to maintain the thickness of the rotary vane above the required strength, it is possible to reduce the rotational resistance due to the thickness of the vane. Further, the replaceable sliding member avoids friction between the bottom of the hopper and the tip of the rotary blade, and the installation of the sliding member has no influence of frictional force. In addition, there is no need to consider scratches that could be affected by breakage or repair, and periodical sliding member replacements are sufficient and maintainability and maintainability are very good.

[Brief description of drawings]

FIG. 1 is a schematic view of a dewatered sludge storage and discharge device of the present invention.

FIG. 2 is a diagram showing details of a rotary blade that is a main part of a scraping unit.

FIG. 3 is a graph showing measured values of torque of a rotary blade.

FIG. 4 is a graph showing the relationship between the rotary blade thickness and the torque / discharge capacity.

FIG. 5 is a graph showing a relationship between a chamfering amount of a rotary blade and a vertical load.

FIG. 6 is a graph showing the relationship between the clearance between rotating blades and the maximum stress applied to the rotating blades.

FIG. 7 is a graph showing the relationship between the clearance between the rotary blades at the guide rail mounting position and the maximum stress applied to the rotary blades.

FIG. 8 is a cross-sectional view of essential parts of a conventional dewatered sludge storage and discharge device.

FIG. 9 is a top view of a main part of a conventional dewatered sludge storage and discharge device.

[Explanation of symbols]

1 Storage discharge device 2 storage tanks 3 bottom 4 scraping part 5 Sludge cutting section (screw) 6 drive shaft 7 rotating blades 8 sludge 11 Guide rail 12 Auxiliary plate (sliding member) 15 chamfer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Norihisa Saito 1-3-18 Wakihama-cho, Chuo-ku, Kobe City Kobe Steel, Ltd. Kobe Head Office (56) Reference JP-A-57-151535 (JP, A) ) JP-A-8-337324 (JP, A) JP-A-53-98666 (JP, A) Sekikaihei 8--1011 (JP, U) JP-B 37-12164 (JP, B1) JP-B 33- 5921 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65G 65/48 C02F 11/00

Claims (5)

(57) [Claims] 1. A frustoconical storage tank for storing dehydrated sludge, a scraping unit for scraping the dehydrated sludge, a sludge discharge port provided at the bottom of the storage tank, and the sludge discharge port. a storage discharge apparatus dewatering sludge comprising a cutting unit, the cutting out the al sludge, the scraper unit comprises a drive shaft projecting from the center of the bottom portion of the reservoir, the solid to the upper end of the drive shaft An apparatus for storing and discharging dewatered sludge, comprising: a rotary vane that is installed to rake up the dewatered sludge and has no rotor portion. 2. The storage of dewatered sludge according to claim 1, wherein the rotary blade is a flat plate having a thickness d arranged in parallel with the bottom portion and having a tapered shape in which the width 1 becomes smaller toward the blade tip. Ejection device. 3. A truncated cone-shaped storage tank for storing dehydrated sludge, a scraping unit for scraping the dehydrated sludge, a sludge discharge port provided at the bottom of the storage tank, and the sludge discharge port. a storage discharge apparatus dewatering sludge comprising a cutting unit, the cutting out the al sludge, the scraper unit comprises a drive shaft projecting from the center of the bottom portion of the reservoir, it is fixed to the drive shaft A dewatered sludge storage and discharge device comprising: a rotary blade that scrapes up the dehydrated sludge, and a circular guide rail that supports the lower side of the rotary blade provided at the bottom portion. 4. The range of radius r ′ from the center of the installation position of the guide rail is 0.55 × r ≦ r ′ ≦ 0.85 ×
The dewatering sludge storage and discharge device according to claim 3, wherein the drainage sludge is r (however, r: radius of a rotary blade, unit: mm). 5. The dewatered sludge storage and discharge device according to claim 3, wherein a replaceable sliding member is attached to the rotary vane facing the guide rail.