JP3021848B2 - Method and apparatus for measuring flow rate of pumped mud - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pumping mud for measuring the flow rate of mud in a flowing state like "anko" while being pumped through a pipe by compressed air mainly in a plug flow in various modes. The present invention relates to a method and an apparatus for measuring a flow rate.

[0002]

2. Description of the Related Art In recent years, as a dredging method for seabeds, lake bottoms, rivers, and the like, a pumping method has been known in which dredged mud is pumped through a pumping pipe provided over a long distance using compressed air.

[0003] In this method, in order to efficiently perform pressure feeding of mud in a pipe, for example, the mud is stirred by a stirring means or the like in a pressure feeding tank to which compressed air for pressure feeding is supplied or before being supplied into the pressure feeding tank. It has been fluidized like "anko". Also, an injection pipe of a solidifying agent for solidifying the mud is installed in the middle of the pumping pipe, and the solidifying agent is mixed into the mud being pumped, so that the mud discharged from the pumping pipe is appropriately solidified, and water seepage at the dumping site is performed. There is no secondary contamination such as taking out.

[0004] Since the mud conveyed in the pressurized pipe exhibits various flow modes mainly by plug flow, the injected solidifying agent is uniformly mixed into the mud. The injection control of the solidifying agent is controlled such that a fixed amount of the solidifying agent is injected into the pumping pipe by measuring the flow rate of the mud.

[0005] By the way, the flow rate measurement of the pumped mud is performed in a batch-type measuring method, that is, at the inlet or outlet at the pipe end, since the mud is a complicated flow having various modes mainly composed of plug flow in the pumping pipe. At present, it relies on volumetric measurement such as measuring boxes.

As a method for measuring the flow rate of the mud in real time, a method using an ultrasonic or electromagnetic sensor has been proposed. However, a malfunction caused by mud particles floating in the pipe causes an inaccurate detection. Was.

[0007] Therefore, there is a problem that the solidifying agent cannot be injected at an optimum ratio into the continuously flowed mud having different flow rates.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to perform real-time accurate flow rate measurement of mud pumped through a pipe in various flow modes mainly by plug flow. There is something you can't do.

[0009]

A method for measuring the flow rate of a pumped mud to solve the problems of the present invention is to provide a method for measuring the flow of the mud pumped in a pipe at two different points and to detect the passage of the mud by a vibration detection method. It is characterized by detecting with a sensor, and detecting the flow rate of the pumped mud from the distance between the sensors, the pipe diameter, the mud passing time between both sensors, and the time until the mud passes.

In order to solve the problem of the present invention, a flow rate measuring device for pumping mud is provided in a contact type provided along a direction of pumping mud at a predetermined interval in a measuring pipe through which mud is pumped. Vibration sensors and the time difference between when these vibration sensors start detecting vibration due to contact with the mud and the sensor interval determine the pumping speed of the mud, the time from the start to the end of the vibration detection, the pumping speed and the measuring pipe. And a calculating means for calculating the flow rate of the mud pumped by the inner diameter.

[0011]

FIG. 1 is a block diagram showing an embodiment of an apparatus for measuring the flow rate of compressed mud which can effectively carry out the method of the present invention.

In the flow rate measuring apparatus according to the present embodiment, a first vibration sensor 1 and a second vibration sensor 2 are attached to a measuring pipe 3 having a diameter d to which mud is pumped at a predetermined interval L. The detection signals from the first vibration sensor 1 and the second vibration sensor 2 are output to a calculation display unit 4 including a microcomputer or the like.

First sensor 1 and second sensor 2
Is a vibrometer main body 10 which is an accelerometer as shown in FIG.
The sensor rod 11 is inserted into the measuring tube 3, and a disc-shaped flange portion 12 formed on the base side of the sensor rod 11 is provided on the front and back sides of an elastic member such as rubber. Rings 13 and 14 are provided, respectively, and the vibrometer main body 10 and the sensor rod 11 are elastically suspended and held by the hold rings 15 and 16 via the O-rings 13 and 14.

The hold rings 15 and 16 are fixed by bolts 17 and nuts 18 and
The mounting flange 19 fixed to the holding ring 1
6, the vibration sensor is fastened to the measuring pipe 3 by a bolt and a nut. In addition, sensor rod 1
The portion inserted into the pipe 1 is inclined along the flow direction, and has a surface coated with a ceramic coating to prevent abrasion due to contact with the pumping mud. The insertion depth of the sensor rod 11 is approximately the center of the pipe in order to achieve sufficient contact with the pumping mud and to enable high-sensitivity vibration detection.

In the vibration sensor thus configured, when the sensor rod 11 detects mud to be pumped through the inside of the measuring pipe 3,
Vibration is performed about the flange portion 12 as a fulcrum,
Detects the vibration and outputs a vibration detection signal.

In this case, the measuring pipe 3 is connected to the pressure feeding pipe. As shown in FIG. 3, in the present embodiment, the measuring pipe 3 is connected between the pressure feeding pipes 20 via a rubber flexible tube 21 so that the pressure feeding pipe is connected. Vibration from the tube 20 is not transmitted to the measurement tube 3.

Next, the flow rate detection operation of this embodiment will be described.

The interval L between the first vibration sensor 1 and the second vibration sensor 2 and the diameter (inner diameter) d of the measuring tube 3 are input to the calculation display section 4 in advance.

When the pumped mud first reaches the first vibration sensor 1 at time T ₁ , as shown in FIG.
The first vibration sensor vibrates and outputs a first detection signal to the calculation display unit. The operation display unit 4 waits for the input of the second detection signal from the second vibration sensor 2 next.
As shown in FIG. 1B, when the mud that has passed through the first vibration sensor 1 reaches the second vibration sensor 2, a second detection signal is similarly output from the second vibration sensor 2 for a time T. _Two
Is output to the calculation display section 4.

Here, the calculation display unit 4 calculates the flow velocity V of the mud according to the following equation (1) and displays this value.

V = L / (T ₂ −T ₁ ) (1) As shown in FIG. 1B, a mass of mud passes through the first vibration sensor 1, that is, When the first vibration of the vibration sensor 1 is stopped at time T _3, and the calculated flow rate of mud pumped during the (Q) according to the following equation (2), and displays this value on the display unit.

[0022] ^{Q = (π · d 2/} 4) × V × (T 3 -T 1) ··· Equation (2) therefore together that may be implanted solidifying agent to the flow (Q) of the mud become.

Then, the integrated flow rate Q 'is obtained from Q' = ΣQ.

[0024]

As described above, according to the present invention,
The vibration sensor vibrates in contact with the mud being pumped through the pipe and detects that the mud is being transferred. Even if it occurs, the vibration sensor continues to vibrate, so that the flow rate of the pumping mud flowing in a complicated manner can be accurately detected without malfunction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a pumping mud flow measuring device according to the present invention.

FIG. 2 is a sectional view showing one embodiment of a vibration sensor.

FIG. 3 is a side view showing an attached state of a measurement tube.

[Explanation of symbols]

 1, 2 Vibration sensor 3 Measurement pipe 4 Calculation display unit 10 Vibrometer main body 11 Sensor rod 13, 14 O-ring

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 1/00 G01F 1/708

Claims (2)

(57) [Claims] 1. The passage of the mud pumped through the pipe differs
At this point, the passage of the mud is detected by a vibration detection type sensor, and the flow rate of the pumped mud is detected from the distance between the sensors, the pipe diameter, the mud passing time between both sensors, and the time until the mud passes. A method for measuring the flow rate of pumped mud, characterized by the fact that: 2. A contact type vibration sensor provided in a measuring pipe to which mud is pumped at a predetermined interval along a mud pumping direction, and these vibration sensors detect vibration by contact with the mud. Calculating means for calculating the pumping speed of the mud based on the time difference between the start and the sensor interval, and calculating the time from the start to the end of the vibration detection, the pumping speed and the flow rate of the mud pumped by the inner diameter of the measuring pipe. A flow rate measuring device for pumping mud.