JPS60208525A - Control on operation of pump dredger - Google Patents

Abstract

PURPOSE:To easily perform optimum dredging operations by a method in which various data on pump-dredging operations are detected, and optimum operational conditions for dredging with an optimum mud water rate on the basis of various data are displayed with detected data. CONSTITUTION:A pump dredger is provided with detectors to detect water depth positions of a cutter 4, suction negative pressures in a suction tube 3, output and revolving number of a pump 2, discharge pressures of a sand discharge tube 5, and flow rate and mud content of mud water discharged. Optimum mud water rate is calculated on the basis of the output of the detectors, and optimum operational conditions based on the optimum mud water rate are displayed with detected data to give operators the operational information. The occurrence of cavitation can thus be prevented, and dredging operations can be performed with good efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for managing the operation of a pump dredger by instructing the operator of the optimum operating conditions at each point in time during dredging operation.

(Prior art) A pump dredger is generally equipped with a large pump 2 for suction inside the hull 1 as shown in Fig. 1, and a suction pipe 3 (indicated by a dashed line in the figure) extending from the pump 2 to the front of the hull 1. ) is equipped with a cutter 4 at its tip for scraping earth and sand on the bottom of the water, and a sand discharge pipe 5 extending from the pump 2 at a far rear end is provided. In FIG. 1, 6 is a ladder housing the suction pipe 3, and 7 is a spud.

During the dredging operation of such a pump dredger, the cutter 4 stirs up the earth and sand at the bottom of the water of a port or river, and the earth and sand together with water turns into gold slurry and is sucked up from the cutter 4 through the suction pipe 3 to the pump 2. The sand is then discharged from the pump 2 to a distant place through the sand discharge pipe 5.

Currently, dredging operations have traditionally relied on the experience and skills of individual drivers based on non-statistical information obtained from various measuring instruments. Therefore, there is a problem that drivers with less experience cannot be entrusted with the driving duties.

By the way, the gold mud ratio, which indicates the concentration of earth and sand in the muddy water that is discharged, is important because it accounts for a large portion of the cost of dredging operations, and it is important to keep this gold mud ratio optimal as the dredging work progresses. It is desirable to have the best work done. However, even for the above-mentioned skilled driver, this was difficult because there was no criterion for judgment.

(Purpose of the Invention) The present invention is intended to solve the above-mentioned problems. To provide a method for managing dredging operation in a pump ship, which allows even an unskilled operator to carry out optimal dredging operation by suggesting information necessary for dredging operation judgment based on the rate.

(Structure of the Invention) In order to achieve the above object, the method of the present invention provides a pump ship equipped with a suction pipe and a sand discharge pipe before and after a suction pump installed in the hull. the submerged position of the cutter during dredging work, the suction negative pressure in the suction pipe, the output and rotational speed of the pump, the discharge pressure in the sand discharge pipe, the water in the sand discharge pipe and the earth and sand flowing with it. Various measuring instruments are installed to detect the discharge flow rate of gold mud water consisting of Based on the detected data, at least the target suction negative pressure, target discharge pressure, and target pump output are calculated using the target value calculation/display device provided in The limits and discharge pressure limits are calculated, and the target suction negative pressure, target discharge pressure, and target pump output are set to any one of the calculated suction negative pressure limits and discharge pressure limits, and a preset pump output limit value. The present invention is characterized in that the rainbow dredging operation is managed by displaying the three types of target values to be reached as the optimum values together with the corresponding detection data.

In the method of the present invention, the suction negative pressure, discharge pressure, and pump output are displayed and displayed because: ■ If the suction negative pressure exceeds the limit, cavitation will occur; ■ If the discharge pressure exceeds the limit, the discharge will occur. If the pump output exceeds its limit, it may become inoperable due to leakage of gold mud from the joint of the pipe, rupture of the discharge pipe system, or overload of the prime mover. It goes without saying that other calculations and displays may also be performed and monitored by the driver.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

In implementing the present invention, corresponding measuring instruments will be installed in the sea urchin pump dredger shown in FIG. 1 to detect various data. That is, in order to obtain water depth data for the cutter 4, two water pressure gauges 8° 8' were attached to the rudder 6 on the same straight line passing through the tip of the cutter 4, and gold mud water was sucked into the suction pipe 3 just before the pump 2. A suction negative pressure needle 9 is attached to measure the suction negative pressure required to increase the suction negative pressure, and the pressure is used to measure the discharge pressure of the pump 2 required to discharge the gold slurry to the part of the sand discharge pipe 5 immediately after the pump 2. a tachometer 11 for measuring the rotation speed of the pump 20 and an output meter 12 for measuring the output of the pump 2 are attached to the drive system of the pump 2;
Further, an electromagnetic flowmeter 15 is used to measure the flow rate of the gold mud water in the sand discharge pipe 5 (discharge flow velocity), and a gold mud ratio is used to obtain the gold mud ratio that indicates the concentration of earth and sand contained in the gold mud water flowing through the sand discharge pipe 5. Install the mud content meter 14.

FIG. 2 shows the various measuring instruments 8.7', 9. 10. 1
Based on the detection data obtained from 1゜12.13.14,
A device (8 dredging value calculation/display device) 15 that calculates and displays the minimum operating requirements 1ii1i required for dredging operation is shown. In the figure, 16 is a scanner, 17 is an interface, 18 is a calculation section, and 19 is a part of a display. Further, 20 represents a printer, 21 an acoustic coupler, and 22 a floppy disk. It should be understood that the target value display/display device 15 is installed in the operator's cabin of the pump dredger.

With the above-mentioned measuring instrument and target value calculation/display device 15,
The implementation of the method of the present invention will be explained using chart 70 in FIG. Now, the water depth of the cutter 4 is hs, the suction negative pressure of the suction pipe 3 is k, the discharge pressure of the sand discharge pipe 5 is Hd, the rotation speed of the pump 2 is N1, the output of the pump 2 is P1, the discharge flow rate of muddy water is Vd.

X (4,5-'/rl white ・・・・・・・・・・・・
- The relationship (1) holds true. Here, formula (1) is derived from "Report on Survey of Construction Capacity of Pump Dredgers and Sludge Dredgers", June 1973, Japan Reclamation Dredging Association, page 49, (
Types 2+ and +31 are “Characteristics of dredging pumps and how to use them”
Derived from Ministry of Transport, Port Technology Research Institute, 1952, page 7.

Further, equation (4) represents an equation for calculating the output of a normal pump.

Note that il+, (21,131 and (4) in the formula, Ga
is the estimated specific gravity of the excavated ground at the bottom of the water (input the value obtained from the polling sample of the ground in advance), Gs is the true specific gravity of the excavated soil particles at the bottom of the water, Dd is the diameter of the sand discharge pipe 5, and ds is the excavated soil particles. β1 is the soil constant on the suction side, C is the inlet loss coefficient of the suction pipe 3, Gm is the specific gravity of the slurry (muddy water), and (xGa+(1)
-xi, Ds is the diameter of the suction pipe 6, g is the gravitational acceleration, λ is the Masatsu loss coefficient, Karasu is the soil constant on the discharge side, Ll is the onboard length of the sand discharge pipe 5, L is the sand discharge pipe L3 is the submerged pipe length and land pipe length of the sand removal pipe 5, hd is the height of the discharge port of the sand removal pipe 5 from the water surface, n is the number of curved pipes that make up the sand removal pipe 5, and cb is the The curved pipe loss coefficient, H is the value of (Hs+Hd), Q is the flow rate (=''/4Dd2XVd), and ηp is the pump efficiency.

In the +11 formula above, it is not possible to measure anything other than the gold mud ratio x1 discharge flow rate Vd, so if the other parts are set as + for the rate constant, (
Equation 1) can be transformed into Equation 01.

Vd = Kl
, (By transforming Equation 31, the constants β1 and β2 can be expressed as the following (6
1, it can be expressed by equation (7).

・・・・・・・・・・・・(6) ・・・・・・・・・, j +71 Furthermore, in the above equation (4), H (=Hs + Hd) and Q( =π/a Dd”
x Vd ), Gm (=x (Ga+(1-x)
) are constants, so if we now set it as the pump output constant 4 and rewrite equation (4), the relationship of equation (41) holds true.

P=KzX(Hd+Hs)XQXGm ・＋・−++・
(4i1 is &=P/(HxQxGm) −・・−
・<81 Therefore, the above relational expression is displayed on the target value display device 15.
As shown in Fig. 3, the measuring instruments a, a', q,
The various data detected from 1o, IL 12.1s and 14 are calculated by the calculation unit 18 of the device 15 to calculate +, Ks, β1. Calculate each constant of β2.

In other words, (the detected gold mud ratio XO and the discharge flow rate Vd are expressed in equation 51.
Substitute oQ to the rate constant at the time of detection + k II out\Similarly, the detected gold mud ratio XOs Suction negative pressure Hs6 and water depth h
Gmo t(6) calculated from s6 and gold mud rate XQ
2 to calculate the suction side soil constant βIk at the time of detection, and substitute the detected gold mud ratio do. Furthermore, the detected pump output Pa, suction negative pressure Hs6, discharge pressure Hdo, and discharge flow rate VdO are (
8) Substitute into the equation to calculate the pump output constant 4 at the time of detection.

Next, as shown in Figure 5, Δ! ? Added gold mud ratio x (=x6+Δx>t-variable, target discharge flow rate Vd at this gold mud ratio Xo+ΔX.

The target suction negative pressure Hs and target discharge pressure Htl are calculated.

In other words, (the rate constant calculated by equation 11 plus 1 variable x6 + ΔX
(2) The suction side soil constant β calculated in 2, the variable XO + ΔNS, Gm calculated from this variable, and V calculated from the discharge flow rate Vd.
Substitute s f to find the target suction negative pressure Is.

Furthermore, the discharge side soil constant β3 calculated using equation (3) and the variable x
Substitute 0+ΔX and discharge flow rate Vd Q to calculate target discharge pressure/force Hd.

Furthermore, (2 to the pump output constant calculated by formula 41, the above target suction negative pressure Hs and target discharge pressure Hd.

Then, the operating pump output P was determined by substituting Q calculated from the target discharge flow rate Vd and Gm calculated from the variable XO+ΔX.

Next, as shown in the chart in FIG. 3, the suction negative pressure limit and the discharge pressure limit kl at the corresponding variable N6+ΔX
put out

If we now assume that the suction negative pressure limit is Hsl, then [Design and Drawing of Centrifugal Pumps] pp. 96-96, written by Susumu Terada, Science and Engineering Tosho 1932
On March 10, 2009, the following four holes were derived from the "Planning Method for Dredging Pumps" (Ehara Jiho Vol. 20, No. 77, reprint, p. 6).

Hsl = 9.0- (NxV71ha350)"...
...O [This formula is stored in the target value calculation/display device 15 in advance, and the detected pump rotation speed N
1. Then, the suction negative pressure limit Hsl is calculated by substituting the flow rate Q determined from the target discharge flow rate Vd.

Also, if the discharge pressure limit is Hdl, this is the pump 2
Its characteristic formula is aυ formula Hdl = Hshut −aOx 10”−’Q”
-・-・・−・−・＠υ There is a relational expression, and this expression is stored in advance in the target value performance/display device type 15 (in this embodiment, the special K Hshut is set to 110), and the aυ expression is Hdl is calculated by substituting the Q value calculated from the target discharge flow velocity Vd determined above.

Note that the pump output limit is known in advance, so its value, especially in this example, 6000, is set to the target value calculation/display device 15.
be memorized in advance.

Next, as shown in the flowchart of FIG. 6, it is determined whether or not the target suction negative pressure Hs reaches the suction negative pressure limit Hsl in the variable x6+ΔX, that is, "YES".

The target value calculation/display device 15 makes a logical judgment as to whether it is "No", and if it is 1-No, the transition is made and a logical judgment is made as to whether the target discharge pressure Hd reaches the discharge pressure limit Hdl (Yes) or not (No). do. Then, "No", Orange and the others proceed further and logically determine whether the target pump output P reaches the pump output limit value 6000 (Yes) or not (No).

If the above judgment is 1 “yes” at any stage,
According to the flow shown in Figure 3, the sedimentation limit flow velocity Ve of the sand discharge pipe is calculated using the following relational expression. (9) In the formula, Ga, Gs
.

Dd and Ds are defined in Equation 11 above, and dog has the same meaning as defined in Equation 15. The claim method is the same as in Equation (1). This is a standard that indicates whether the flow in the sand discharge pipe is slow and there is a risk of clogging with sand or not.This limit value Ve is displayed on the display part 19.Next, the target suction negative pressure at that point is Hs
, the target discharge pressure Hd and the limit pump output P are displayed together with the corresponding detection data on the display part 19 of the target value inducement/display device 15 as indicating the instantaneous optimum values immediately after detection. Then, the process returns to the above-mentioned starting point again, detects various data, and calculates and displays the optimum target value based on this data.

On the other hand, in the above logical judgment, if the result is 1 NO at any stage, increase the Δχ value in the variable
The above logical judgment is repeated until "yes" is determined for any one of the relationships between d and the discharge pressure limit Hdl, and between the target pump output P and the pump output limit value 6000. If "Yes" is determined, the optimal target value will be displayed in part 1 along with the corresponding detection data in the same way as above as indicating the sedimentation limit flow velocity value and the instantaneous optimal value immediately after detection.
Displayed at 9.

In this way, the optimal target values immediately after each detection and the detected data calculated based on the various data continuously detected during dredging work are calculated as follows: This is shown in Figures 4 to 8. In each figure, the horizontal axis shows time (minutes), and the vertical axis shows the gold ratio (%) in Fig. 4 and the suction negative pressure (wnHg) k in Fig. 5.
, in Fig. 6, the discharge pressure (K9f/lri) k
, FIG. 7 shows the pump output (P, S)'r, and FIG. 8 shows the discharge flow rate (m/see l).

The driver then looks at information on the optimal target suction negative pressure, target discharge pressure, and target pump output that is displayed over time, and performs driving operations to meet these optimal operating conditions. This makes it easy to operate optimally even if you are not very experienced. - Moreover, since each operating condition is below the limit value, it is possible to prevent pump cavitation that would occur if the limit value were greatly exceeded, and sedimentation of sediment in the suction pipe and sand discharge pipe.

(Effects of the Invention) As explained above, according to the present invention, various data are continuously detected during dredging work, and the moment immediately after each detection is calculated based on the detected data and the optimum gold mud ratio immediately after the detection. The system displays the optimum operating conditions at the minimum along with the corresponding detection data and provides information that will suggest the operator's operational decisions, thereby completely preventing pump cavitation and preventing sediment from leaking from the suction pipe or sand discharge pipe. Even non-experts can easily perform optimal dredging operations without the need for dredging to become inoperable due to insufficient pump output.

Moreover, the gold mud ratio can always be kept at the optimum condition, and the efficiency of dredging operation can be greatly improved.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an outline of a pump ship used to implement the method of the present invention, and Fig. 2 is a schematic block diagram showing the relationship between various measuring instruments arranged in the one shown in Fig. 1 and a target value calculation/display device. 3 is a diagram showing a flowchart of the target value calculation/display device in FIG. It is a graph showing the relationship between discharge pressure, pump output, discharge flow rate, and time. 1... Hull of pump dredger 2... Pump 3...
Suction pipe 4... Cutter 5... Sand discharge pipe 6... Ladder 8.8'... Pore water pressure gauge 9... Suction negative pressure needle 10.
...Pressure gauge 11...Tachometer 12...Output meter 13...Electromagnetic flow meter 14...Gold rate meter 15...Target value calculation/display device 18...Calculation section 19... Display section (#Oka or 1 person)

Claims (1)

[Claims] (I) A pump dredger that is equipped with a suction pipe and a sand discharge pipe before and after a suction pump installed on the hull, and the underwater position of a cutter located at the tip of the suction pipe during dredging work, and the suction The suction negative pressure in the pipe, the output and rotation speed of the pump, the discharge pressure in the sand discharge pipe, the discharge flow rate of muddy water consisting of water in the sand discharge pipe and earth and sand flowing together with it, and the gold slurry water. Various measuring instruments are installed to detect the gold mud ratio, which indicates the concentration of soil in the dredging, and various data are detected during dredging work from the various measuring instruments. Based on the detection data, at least a target suction negative pressure, a target discharge pressure, and a target pump output are calculated using the gold mud ratio as a variable, and then the suction negative pressure limit and the discharge pressure limit tS at the gold mud ratio are calculated, and the target suction negative pressure is calculated. When the pressure, target discharge pressure, and target pump output reach any one of the calculated suction negative pressure limit, discharge pressure limit, and preset pump output limit value, the target value of the three poles is set as the optimal value. A dredging operation management method in a pump dredger, characterized in that dredging operation is managed by displaying the dredging operation together with corresponding detection data.