JPH0146165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for automatically detecting the occurrence of uneven pressure on a filter plate in a filter press.

Conventional technology Conventionally, in the squeeze filtration process in a filter press, a large amount of cake accumulates near the entrance of the filter chamber due to the properties of the raw solution, and the pressure inside the filter chamber becomes lower than the pressure inside other filter chambers. It was hot.
In this case, when there is a difference in pressure between adjacent filter chambers and so-called uneven pressure occurs, the filtration surface of the filter plate between the two filter chambers is pushed by the higher pressure, and the pressure of the lower pressure chamber is pushed. There was a problem in that the filter bulged toward the filter chamber side, and in severe cases, cracks appeared on the filter surface, impeding the filtering operation.

Purpose of the Invention As a result of intensive research to solve the above problem, the inventors have found that when the above-mentioned uneven pressure occurs during press filtration, the filtration surface is deformed due to this. It was discovered that the hanging arms on both the left and right sides of the filter plate are also deformed so that they are no longer parallel to the hanging arms of other filter plates, leading to the completion of this invention.

The purpose of this invention is to
A filter that can easily and reliably detect the occurrence of uneven pressure from the outside of the filter plate, prevent deformation of the filter plate due to uneven pressure, and ensure smooth filtration work using a filter press. The object of the present invention is to provide a method for automatically detecting the occurrence of uneven pressure on a filter plate in a press.

Composition of the Invention In order to achieve the above object, the present invention provides a required number of filter plates provided in a filter press with detection bars protruding outward from each other, and in a closed state of the filter plates, all the detection bars At the same time, a movable body equipped with sensors that can be moved back and forth is placed near the filter plate, and the movable body with the sensor is moved at a constant speed during compression filtration using the filter plate in the closed state. The gist of this paper is a method for automatically detecting the occurrence of uneven pressure on a filter plate in a filter press, which is characterized by detecting the occurrence of uneven pressure on the filter plate by detecting an abnormality in the arrangement interval of detection bars using a sensor.

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

In this specification, the term "front" refers to the first head side, and the term "rear" refers to the rear head side. In addition, left and right mean toward the rear.

In Figures 1 to 6, the filter press 2
1 is fast head 22, loose head 2
3. It mainly consists of a rear head 24, a pair of left and right side plates 26, and a large number of filter plates 25 arranged between the first head 22 and the loose head 23. Hanging hands 2 are provided on the left and right sides of the filter plate 25, respectively.
7 are provided, and these hanging hands 27 are attached to the side plate 2.
By being placed on the upper edge of the filter plate 25
is slidably supported.

The stock solution supply port 3 is located in the center of the filter surface 28 of each filter plate 25.
0 is provided, and a filtrate outlet 31 is provided at the lower left corner, which communicates with the filtrate passage. Further, a detection bar 33 is attached to the upper center of each filter plate 25 in an upwardly protruding manner.
In the closed state, all the detection bars 33 are arranged at equal intervals. The lower half of the detection bar 33 is inserted into the insertion hole 34 at the center of the upper part of the filter plate 25, and the portion 34a of the insertion hole 34 corresponding to the frame 29 of the filter plate 25 is smaller than the outer shape of the detection bar 33. Also, the detection bar 33 is designed to be large so that the detection bar 33 is easily tilted as the filter surface 28 expands and deforms due to uneven pressure.

A guide frame 36 having a U-shaped cross section is horizontally arranged above the filter press 21, and both front and rear ends of this frame 36 are connected to the first head 22.
The rear head 24 is supported by pillars 37 and 38 provided in an upright manner. Chain guide rails 39 are attached to the upper surfaces of the upper and lower horizontal parts 36a and 36b of the guide frame 36, respectively, and are guided by the upper and lower straight parts of an endless roller chain 42 that is wound around a pair of front and rear sprockets 40 and 41. - Each is guided by the rail 39. The chain 42 is rotated forward or reverse by a reversible motor 48 provided on the rear support column 38. Lower horizontal portion 36b of chain 42
A moving body 43 is attached on the way. The moving body 43 is composed of a mounting plate 44, a horizontal bracket 45 extending to the left side of the mounting plate 44, and a pair of left and right vertical brackets 46 provided at a predetermined distance from each other on the lower surface of the horizontal bracket 45. . The mounting plate 44 of the movable body 43 is slidable on a slide rail 47 longitudinally attached to the inner surface of the vertical portion 36c of the guide frame 36 via a holding member 59 containing a number of rolling balls. are guided by. A pair of left and right vertical brackets 46 of the movable body 43 are equipped with optical fiber photoelectric switches 50 as sensors, each of which includes a light projector 51 and a light receiver 52 facing each other. A photoelectric switch body 53 is attached to the upper surface of the horizontal bracket 45 via an L-shaped bracket 49. The photoelectric switch main body 53, the light projector 51, and the light receiver 52 are each connected by an optical fiber cable. Further, a front light shielding plate 54 is attached to the upper end of the first head 22 so as to be lined up with the first detection bar 33 at a distance l, and a rear light shielding plate 55 is attached to the upper end of the loose head 23 so as to connect the last detection bar 33. They are attached so that they are lined up with an interval l between them. In this embodiment, the length of the rear light shielding plate 55 in the front-rear direction is longer than the length of the front light shielding plate 54 in the front-rear direction. A signal indicating a change in the amount of received light from the photoelectric switch 50 is sent to a control panel 56. A stock solution supply pipe 57 is connected to the first head 22, and a stock solution supply pump P and a valve 58 are interposed in the middle of the stock solution supply pipe 57. The stock solution supply pump P and the photoelectric switch moving motor 48 operate based on signals from the control panel 56.

In the filter press 21 described above, the method for automatically detecting the generation of partial pressure in the filter plate 25 according to the present invention is applied in the seventh embodiment.
This will be explained based on the diagram.

First, during compression filtration with the filter plate 25 in the closed state (see FIG. 1), the stock solution is supplied into each filter chamber 32 through the supply pipe 57 and the first head 22 by the operation of the stock solution supply pump P (step 1). on the other hand,
The endless roller chain 42 is rotated by the operation of the photoelectric switch moving motor 48, and the movable body 43 and the photoelectric switch 50 integrated therewith are moved to the slide rail while the compression filtration is being performed or at any time during that period. 47 and between the fast head 22 and loose head 23 (step 2). Then, the photoelectric switch 50 detects the occurrence of biased pressure on the filter plate 25 in the following manner.

That is, in the compression filtration process, when the photoelectric switch 50 is first located above the loose head 23 and the photoelectric switch 50 is turned on (step 3), a light beam is emitted from the emitter 51 of the photoelectric switch 50 and reaches the receiver 52. is first blocked by the rear light shielding plate 55, and the amount of light received by the light receiver 52 becomes zero. After passing through the rear light shielding plate 55, the minimum reference time T1 provided in the control panel 56
The timer turns on (step 4). The actual measurement value T of the transit time from the rear light shielding plate 55 to the detection bar 33 of the next filter plate 25 due to the movement of the photoelectric switch 50 is calculated in advance from the distance l between the two and the moving speed of the photoelectric switch 50. It is checked whether the set passing time exceeds the minimum reference value T1 (step 5). When the minimum reference value T1 is exceeded, the timer for the passing time allowable reference value T2 is turned on at the same time as the minimum reference value T1 is exceeded (step 6), and then a check is made to see if the actual measured value T of the passing time further exceeds the allowable reference value T2. Look (Step 7). If the allowable reference value T2 is not exceeded, the light beam is blocked by the tip of the detection bar 33 within this time range, the amount of received light becomes zero, and the photoelectric switch 50 is turned off (step 8). In this state, a normal operation indicator lamp (not shown) lights up (step 9). When the light beam passes through this detection bar 33, the amount of light received increases and the photoelectric switch 50 is turned on again, and in the same manner, the light beam passes through the detection bar 3 of the next filter plate 25.
3 and the above operation is automatically repeated.

For example, as shown by the two-dot chain line in FIG. 2, if the measured value T of the transit time of the light beam between the detection bars 33 of the adjacent filter plates 25 in step 5 is less than the minimum reference value T1. (T<
At T1), the light beam is blocked by the tip of the detection bar 33, the amount of received light becomes zero, and the photoelectric switch 50 is turned off (step 10 in FIG. 7). This signal immediately sounds an alarm (step 11).
The stock solution supply pump P is stopped (step 12), and the photoelectric switch moving motor 48 is also stopped (step 13). Furthermore, as shown by the solid line in FIG. 2, in step 7, the actual measured value T of the transit time of the light beam between the detection bars 33 exceeds the sum (T1+T2) of the minimum reference value T1 and the allowable reference value T2. (T>T1+T2), the alarm will sound immediately (7th
Figure step 11), stock solution supply pump P and motor 48
and stops (steps 12 and 13). Due to these, uneven pressure is generated on the filtration surface 28 of the filter plate 25, and it is certain that the filtration surface 28 is deformed so as to bulge into the filtration chamber 32 at either the front or the rear. .

Note that the passage time of the light beam when the compression filtration is performed normally is the detection bar 3.
It is determined by the distance l between the three comrades and the moving speed of the moving body 43, that is, the photoelectric switch 50. For example, if this is 2.7±0.3 seconds, the minimum reference value T1 of the light beam passage time is 2.4 seconds. , and the allowable reference value T2 after this is 0.6 seconds.

In addition, in the compression filtration process of the filter press 1, the light beam of the photoelectric switch 50 hits the detection bar 33 of the filter plate 25 due to the advance of the moving body 43 as described above.
The light passes from behind to cross the front light shielding plate 54, and finally reaches the front light shielding plate 54. Since the length of this front light shielding plate 54 in the front-rear direction is longer than that of the detection bar 33,
The state in which the amount of received light remains zero continues for that long, and upon sensing this, the photoelectric switch moving motor 48 is reversed, and this time the photoelectric switch 50 is moved backward.
In the same manner as described above, the generation of biased pressure on the filter plate 25 is detected while moving backward. Furthermore, when the photoelectric switch 50 returns to the rear light shielding plate 55, its length in the front and back direction is longer than the front light shielding plate 54, so this is sensed and the photoelectric switch moving motor 48 is reversed, and the photoelectric switch 50 moves forward, and the above detection operation is automatically repeated. Note that switching between the forward and reverse directions of the motor 48 at the starting end and the ending end of the movement process of the photoelectric switch 50 may be performed by a limit switch.

In the above embodiment, the detection bar 33 is attached to the top of the filter plate 25, but it may be attached to the left or right side of the filter plate 25. Further, the means for attaching the detection bar 33 is not limited to the one shown in the drawings, and may be attached to the filter plate 25 by other means.

Further, the photoelectric switch 50 is not limited to the transmission type shown in the drawings, but may also be a coaxial reflection type or a direct reflection type photoelectric switch.

Furthermore, in addition to photoelectric switches, other sensors such as infrared sensors, ultrasonic sensors, etc. can also be used.

Effects of the Invention As described above, the method for automatically detecting the occurrence of partial pressure on a filter plate in a filter press according to the present invention is as follows: Board 25
In the closed state, all the detection bars 33 are installed so as to be arranged at equal intervals, and a movable body 43 equipped with a sensor 50 and movable back and forth is arranged near the filter plate 25. 25, the moving body 43 with the sensor 50 is moved at a constant speed, and the sensor 50 detects the detection bar 3.
This system is characterized by detecting the occurrence of uneven pressure on the filter plate 25 by detecting an abnormality in the arrangement interval l of No. 3. It can be detected easily and reliably from the outside, deformation of the filter plate 25 due to uneven pressure can be prevented, and the filtration work by the filter press can always be carried out smoothly.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially omitted side view of a filter press, and FIG. 2 is an enlarged sectional view of a filter plate, showing a case where partial pressure is generated in the filtration process. FIG. 3 is an enlarged front view of the filter plate, FIG. 4 is an enlarged sectional view taken along the - line in FIG. 3, and FIG. Figure-corresponds to line. FIG. 6 is an enlarged side view of the same portion, and FIG. 7 is a block diagram showing an example of a control circuit of the partial pressure generation detection device. 21... Filter press, 25... Filter plate, 3
2... Filter chamber, 33... Detection bar, 42... Roller chain, 43... Moving body, 48... Photoelectric switch movement motor, 50... Photoelectric switch (sensor), P... Stock solution supply pump.

Claims (1)

[Claims] 1. Detection bars 33 are provided on each of the required number of filter plates 25 provided in the filter press in an outwardly projecting shape, and all detection bars 3 are provided in the closed state of the filter plates 25.
3 are arranged at equal intervals, and a movable body 43 equipped with a sensor 50 and movable back and forth is arranged near the filter plate 25, and the filter plate 2 in a closed state is
At the time of compression filtration by 5, the moving body 4 with sensor 50
3 is moved at a constant speed and the sensor 50 detects an abnormality in the arrangement interval 1 of the detection bars 33, thereby detecting the occurrence of uneven pressure on the filter plate 25. Automatic occurrence detection method.