JPH09178525A - Flow rate measuring apparatus for sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the flow rate of sludge effectively through a simple structure by jetting a specified quantity of water into an enclosed pipe for feeding sludge, measuring the moisture of sludge, and then operating the flow rate, based on the difference between the water jetting time and moisture measuring time and the distance between the water jetting point and moisture measuring point. SOLUTION: The switching means 22 for a jetting means 2 is opened, based on a signal e0 received from an operating means 5 at an appropriate timing t0 to jet a specified quantity of water W through a nozzle 22 to sludge B flowing through an enclosed pipe 1. Consequently, the sludge B containing water W flows through the pipe 1 at a specified current velocity. A moisture measuring means 30 detects the moisture through a photoconductor 31 at a moisture measuring tine t1 and delivers a measurement signal e1 to an operating means 5 if the detected value exceeds a specific threshold value. The operating means 5 operates the flow rate F of sludge B, based on the difference T1 between the water jetting time t0 of water jetting means 2 and the moisture measuring time t1 and the distance L1 between the water jetting means 2 and the measuring point (photoconductor 31).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an apparatus for measuring the flow rate of sludge in a sewage treatment plant or the like.

[0002]

2. Description of the Related Art For example, in a sewage treatment plant, sewage is subjected to treatments such as precipitation, concentration, and dehydration to obtain dehydrated sludge cake, which is transported by a closed pipe, a screw conveyor, a belt conveyor, etc.
Perform processing such as drying and incineration.

Then, the flow rate of sludge is measured and dried,
It is desired to use it for control and management such as incineration.

[0004]

For example, although it has been attempted to measure the flow rate of sludge with an electromagnetic flow meter, stable and accurate measurement is not possible due to the influence of an oxide film inside the closed pipe, surface abrasion, etc. It was difficult.

In view of the above points, an object of the present invention is to provide a sludge moisture measuring device having a simple structure and capable of effectively measuring the sludge flow rate.

[0006]

According to the present invention, there is provided a jetting means for jetting a predetermined amount of water from the outside to the inside of a sealed pipe to which sludge is sent, and an outside to the inside of the sealed pipe provided at a predetermined distance from the jetting means. At least one moisture measuring means for projecting and receiving light through a light guide inserted into the sludge to measure the moisture content of the sludge, and the time difference between the moisture jetting time of the jetting means and the moisture measuring time of the moisture measuring means and the like. The sludge flow rate measuring device is provided with a calculating means for calculating the flow rate of sludge based on the distance.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 is a closed pipe through which the sludge B is sent, and a jetting means 2 capable of jetting water W into the inside is provided at a required position of the closed pipe 1. The jetting means 2 controls the jetting of the nozzle 21 that is inserted and installed from the outside of the closed pipe 1 to jet a predetermined amount of water W from the outside of the closed pipe 1 and the water W supplied from a water source from the nozzle 21. Opening / closing means 2 such as a solenoid valve for operating
2 and so on. Also, a first moisture measuring means 30 for measuring the moisture content of sludge by projecting and receiving light through an optical conductor 31 inserted from the outside to the inside of the closed pipe 1 at a position separated by a predetermined distance L1 from the jetting means 2. First moisture measuring means 3
There is provided a second water content measuring means 40 for measuring the water content of the sludge by projecting and receiving light through an optical conductor 41 which is inserted from the outside to the inside of the closed pipe 1 at a position separated by a predetermined distance L2 from 1. Then, while controlling the timing of water ejection of the water ejection means 2, the water ejection time and the water content measuring means 3 are controlled.
The time difference between the moisture measurement times of 0 and 40 and the distance L between them
PC that calculates the flow rate of sludge based on 1, L2, etc., C
A calculation means 5 such as a PU is provided. The light guides 31 and 41 are optical fibers or the like, through which light of a wavelength absorbed by water and light of a wavelength not absorbed by water are projected and received to measure the water content of the sludge based on the ratio. The measuring means 30, 40 such as a meter is used.
Further, the measurement surface of the end surface of the tip of the light guide 21 is formed to be inclined with respect to the light projection axis, and the measurement surface at the tip is polished because sludge B always passes in close proximity and is rubbed to maintain a good smooth surface. Moreover, it prevents the specular reflection on the measurement surface and enables stable measurement.

Next, the operation will be described with reference to FIG.
At time t0 of appropriate timing, the signal e0 of the calculation means 5
The opening / closing means 22 of the ejection means 2 is driven by the
From the nozzle 21 to the sludge B flowing through the closed pipe 1. Then, the sludge B containing a large amount of water flows at a predetermined speed, and at time t1, the water content measuring means 30 detects a water value higher than usual via the first light guide 31, and this is higher than a predetermined threshold value. At this time, a measurement signal e1 is generated, and this signal is output to the calculation means 5.

Here, the calculation means 5 calculates the flow rate F of the sludge B based on the time difference T1 between the water ejection time t0 of the ejection means 2 and the water measurement time t1 of the water measurement means 30 and the distance L1 between them.
Is roughly calculated by the following equation.

F = S · L1 / T1 (1) where S is the cross-sectional area of the closed pipe 1. Alternatively, the differential signal e3 obtained by differentiating the output signal e2 of the water content measuring means 30 may be used to compare with an appropriate threshold value, and the time may be detected more accurately to measure the flow rate. For example, the average of the generation times of the positive differential signal and the negative differential signal may be used to detect the time t1 and measure the flow rate.

Further, the sludge B containing a large amount of water flows at a predetermined speed, and at time t2, the water content measuring means 40 detects a higher water content than usual through the second light guide 41, and this is a predetermined threshold value. In the above case, the measurement signal e2 is generated, and this signal is output to the calculation means 5.

Here, the calculating means 5 roughly calculates the flow rate F of the sludge B based on the time difference T2 between the moisture measuring times t1 and t2 of the first and second moisture measuring means 30 and 40 and the distance L2 between them. You may make it calculate by a formula.

F = S · L2 / T2 (2) In this case, the calculation means 5 can perform the calculation without knowing the ejection time of the ejection means 1. Further, the differential signal e3 obtained by differentiating the output signal e2 of the water content measuring means 40 may be used and compared with an appropriate threshold value, and the time may be detected more accurately in the same manner. For example, the flow rate may be measured by detecting the times t1 and t2 by using the average of the generation times of the positive differential signal and the negative differential signal.

The jetting cycle of the water W of the jetting means 2,
The timing may be appropriately determined as necessary and the ejection operation may be performed.

By the way, the water content measuring means 30 and 40 may obtain the water content M and the organic matter content N of the sludge B based on the light of a plurality of wavelengths. For example, as proposed by the applicant in Japanese Unexamined Patent Publication No. 7-294426, the signal s of the light component of the first wavelength that absorbs water and the light of the second wavelength that is absorbed by the organic substance Based on the signal r1 of the component and the signal r2 of the component due to the light of the third wavelength which is not absorbed by moisture or organic matter, the moisture content M and the organic matter content rate N are calculated by the following equations by mutual correction.

M = F (x) · G (y) (3) N = H (y) · I (x) (4) Here, F, G, H, and I are predetermined values obtained by experiments in advance. In the function, x = s / r2 and y = r1 / r2. Then, the sludge amount Z is obtained from the flow rate F, and the water amount W is given by the following formula by multiplying the sludge amount Z = W + D (D is an absolute dry weight) by the water content M.

W = Z · M (5) Since the absolute dry weight D is the sum of the organic matter content V and the inorganic matter content d, the organic matter content rate N is as follows.

N = V / (V + d) = V / D (6) Then, the organic matter content rate V can be calculated by V = N · D (7). Note that D = Z−W = Z (1−
M). In this way, in addition to the flow rate, various physical quantities such as water content and organic matter content can be obtained,
It is possible to greatly automate the sludge treatment process.

[0019]

As described above, according to the present invention, the jetting means for jetting a predetermined amount of water from the outside to the inside of the closed pipe to which sludge is sent, and the outside of the closed pipe provided at a predetermined distance from the jetting means. From at least one moisture measuring means for measuring the moisture content of the sludge by projecting and receiving light through a light guide inserted inside, and a time difference between the moisture ejection time of the ejection means and the moisture measurement time of the moisture measurement means, and the like. The sludge flow rate measuring device is provided with a calculation means for calculating the flow rate of sludge based on the distance between the two. That is, it is possible to easily measure the sludge flow rate by ejecting water into the flowing sludge and measuring the water at a remote position. Physical quantity can be calculated,
The sludge treatment process can be fully automated and comprehensively managed. Further, by using the differential signal of the water content measurement signal when measuring the sludge, the time can be known with higher accuracy, and high-accuracy flow rate measurement becomes possible. Further, by providing the moisture measuring means at a plurality of locations, the flow rate can be measured without knowing the ejection time of the moisture ejecting means, and by providing a large number of moisture measuring means at the required locations, the flow rate distribution and the like can be known. Yes, comprehensive sludge treatment becomes even easier.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is an operation explanatory diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealed pipe 2, Jetting means 31, 41 Optical conductor 30, 40 Moisture measuring means 5 Computing means

Claims (4)

[Claims] 1. A spout means for spouting a predetermined amount of water from the outside to the inside of a sealed pipe to which sludge is sent, and a light conductor provided at a predetermined distance from the jet means and inserted from the outside to the inside of the sealed pipe. Moisture measuring means for projecting and receiving light to measure the moisture content of sludge, and computing means for computing the flow rate of sludge based on the time difference between the moisture ejection time of the ejection means and the moisture measurement time of the moisture measurement means and the distance between the two. And a sludge flow rate measuring device. 2. A jetting means for jetting a predetermined amount of water from the outside to the inside of a sealed pipe to which sludge is sent, and a light guide which is provided at a predetermined distance from the jetting means and is inserted from the outside to the inside of the sealed pipe. A plurality of moisture measuring means provided separately from each other for projecting and receiving light through to measure the moisture content of the sludge, and a computation for calculating the flow rate of the sludge based on the time difference between the moisture measurement times of these moisture measuring means and the distance between the two. And a means for measuring sludge flow rate. 3. The sludge flow rate measuring device according to claim 1, wherein the calculating means calculates the flow rate by using a differential signal obtained by differentiating the output signal of the moisture measuring means. 4. The sludge flow rate measuring device according to claim 1, wherein the water content measuring means obtains the water content and the organic matter content of the sludge based on light of a plurality of wavelengths.