JPS5813190A - Transfer of slurry by pump - Google Patents

Abstract

PURPOSE:To prevent coal particles from clogging by measuring a suction pressure and a discharge pressure of a slurry transfer pump and a current of a pump driving motor, computing a concentration or a density of slurry on the basis of the measurements, and supplying fresh water if the computed value exceeds a reference. CONSTITUTION:Pressure gauges 18, 19 and 20, 21 are disposed at suction sides and discharge sides of a suction pump 13 and a transfer pump 16 respectively, and ammeters 22, 23 are mounted to motors (not illustrated) for driving those pumps 13, 16 respectively. Those pressure gauges 18, 19, 20, 21 and ammeters 22, 23 are connected to an arithmetic controller 24 comprising a computer. Fresh water supply pipes 25, 26 open at the bottom of a hold 11 and at the upper part of a slurry storage tank 15, respectively. During transfer of slurry, output signals of the pressure gauges 20, 21 of the transfer pump 16 and the ammeter 23 are sent to the arithmetic controller 24, which computes a density of slurry from the measurements thereof. Based on the result, the controller controls opening or closing of a valve 28 of the fresh water supply pipe 26 of the tank 15 so that coal particles may be prevented from clogging.

Description

[Detailed description of the invention] The present invention relates to a method for transferring slurry using a pump.

For example, when pumping slurry such as coal or iron sand from a slurry transport ship and discharging it ashore, if the concentration of the slurry is high, particles in the slurry may clog the slurry or the transfer piping, or the pump motor may become overloaded. This may cause inconveniences such as an excessive amount of Therefore, during slurry transfer,
Although it is necessary to monitor the concentration, no method has been proposed that can easily measure the concentration of slurry during transport.

An object of the present invention is to provide a method for transporting slurry that can easily and reliably measure the concentration or density of slurry being transported, thereby suppressing the concentration or density of slurry below a certain value.

In order to achieve the above object, the slurry transfer method according to the present invention measures the suction pressure and discharge pressure of the slurry transfer pump and the current of the pump drive motor, and calculates the slurry concentration or slurry density from these measured values. The method is characterized in that fresh water is supplied to the slurry when the slurry concentration or slurry density exceeds a certain reference value.

The present invention will be described in detail below with reference to the drawings.

The drawing shows a part of the slurry landing equipment of a coal slurry transport ship, in which a high-pressure water injection nozzle a is provided at the bottom of each hold αD, and a slurry suction pipe A1 equipped with a slurry suction pump 13 is connected. The other end of the suction tube circle is placed above the slurry storage tank a9. A slurry transfer pump +16 is installed at the bottom of this tank a9.
1 is connected to one end of a slurry transfer pipe αη. Suction pump (
13 and a transfer pump (IQ), pressure gauges αtoss' (Company) are installed on the suction side and discharge side, respectively, and an ammeter @
are provided respectively, and these pressure gauges α mark α9
1□ (21) and the ammeter @ (to) are connected to an arithmetic and control unit equipped with a computer.

Fresh water supply pipes (251 (261) are installed at the bottom of the hold aD and the top of the slurry storage tank αS, respectively, and the operating valves connected to the arithmetic and control unit' (to) are connected to each fresh water supply pipe
attached to the mother.

The coal slurry loaded in the cargo hold α1) of the above transport ship is dehydrated to some extent during loading or during navigation, and when unloading at the unloading port, the nozzle Q2+
High-pressure water is sprayed at the tip. The slurry to which an appropriate amount of water has been added in this way is sucked into a suction pipe (by a suction polep 0:1) and collected in tank a9, and then sent to land via a transfer pipe αη by a transfer pump Q6. be transported. Note that it is also possible to transport the coal slurry without dehydrating it and unload it as is.

During slurry transfer, pressure of transfer pump Q61; it (2
The output signals of 01 (211 and ammeter @) are continuously used for calculation control, the slurry ρ is calculated from these measured values, and based on this result, the valve (branch) of the fresh water supply pipe of tank 05 is
control opening and closing. That is, the current value of the pump drive motor measured by the ammeter @5 is A, the pressure gauge (20 (2
The suction pressure of pump QB+ measured by 1) is P6,
The same discharge pressure is Pd, and the differential pressure between them is P=Pd-Ps
, the water head of pump Q61 is H=P/ρ, and the discharge amount of pump Oe is Q, then the current value A is the discharge amount Q and the differential pressure P.
The discharge amount Q is expressed as a function of the water head H as shown in equation (1), and the discharge amount Q is expressed as a function of the water head H as shown in equation (2).

A=f(Q,P) ・・・・・・・・・・・・(1)
Q)=f (H) =f (P/ρ)+111-(2)
In these equations +11 +21, the two unknowns are the slurry density ρ and the discharge amount Q, and the others can be found directly from the above measured values, so by solving the equation fil (21), the slurry density ρ and the discharge amount Q can be calculated. When the slurry density is greater than a certain reference value, the controller opens valve ① to supply fresh water to tank Q51, thereby reducing the slurry density.Also,
When the slurry density becomes considerably smaller than the above reference value while valve (2) is open, valve (2) is closed to stop the supply of fresh water. In this way, the slurry density is kept below a certain value, and since there is a certain relationship between the slurry density and the slurry concentration, the slurry concentration is also kept below a certain value,
If the transfer pipe aη is clogged with coal particles or the transfer pump (161
There is no risk of excessive load being applied to the motor. Note that, as described above, since the slurry density and the slurry concentration have a certain relationship, it is also possible to calculate the slurry concentration instead of the slurry density and control the opening and closing of the valve (2) in the same manner as above.

In addition, the arithmetic and control unit @ calculates the weight of coal flowing in the transfer pipe aη per unit time (instantaneous feeding amount) by multiplying the slurry density or slurry concentration by the discharge amount, and
The cumulative amount of coal transferred is calculated by summing up the amount of transferred coal, and these values are displayed as necessary.

In addition, during slurry transfer, the suction pump a sudden pressure gauge a seconds α
The output i of the main and ammeter (sub) is also continuously sent to the arithmetic and control unit (sub), and similarly to the above, the arithmetic and control unit (incorporated) is connected to the fresh water supply pipe (c) at the bottom of the hold 0υ. -Valve (a)
control. Furthermore, the bottom of the hold (11) or the suction (15)
) If the pipe is clogged with coal particles, the calculated value of slurry density may become abnormally small, or the measured value of pressure gauge α9 may become abnormal. ,
When such an abnormal phenomenon is detected, the valve cylinder is opened and the hold O1J is closed.
By supplying fresh water to the bottom, clogging of coal particles and coal particles is prevented.

Incidentally, a device similar to the above can be installed in a facility for loading coal slurry onto a transport ship, and similar control can be performed.

Slurry transfer method according to the present invention (applicable to transfers other than unloading and loading of coal slurry, and can even be applied to slurries other than coal.) As described above, according to the present invention, By suppressing the concentration or density of the slurry to a certain value or less, it is possible to prevent clogging of particulate matter in the slurry and overloading of the pump driving motor. Furthermore, the concentration or density of the slurry can be easily and reliably measured using a pressure gauge and an ammeter.

[Brief explanation of the drawing]

The drawing is a schematic pipe diagram showing one example of an apparatus for carrying out the method of the present invention. α5)・Fist・Slurry storage tank, ao...Slurry transfer pump, 07)...Slurry transfer pipe, (201(
211...Pressure gauge, voice/ammeter, (to)...arithmetic control unit, (26)...fresh water supply pipe, (c)...
Operation valve. ' or more 4 people

Claims (1)

[Claims] Measure the suction pressure and discharge pressure of the slurry transfer pump αe and the current of the pump drive motor, calculate the slurry concentration or slurry density from these measured values, and when the slurry concentration or slurry density exceeds a certain reference value A method for transferring slurry using a pump, characterized in that fresh water is supplied to the slurry.