JPH0323454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge device that can cut and transport powder and granular materials with the same precision even when the transport amount changes widely when transporting powder or granular materials using one pressurized tank.

(Prior Art) A device for transporting powder and granules from one tank to multiple locations evenly or at a desired distribution ratio has already been provided by the present applicant and is well known (Japanese Patent Application Laid-Open No. 74426/1982).
However, in such a device, the load cells for measuring the weight of the tank are usually used as a set (a set of three load cells having the same measurement range).

Generally, the measurement range of a load cell is set to a predetermined range (rated capacity) at the time of design, so
Even if the sensitivity of the load cell is high, if the cutout amount is set small in this load cell, the accuracy will decrease.

For example, if the minimum unit of resistance voltage conversion output obtained from a load cell with a load cell range of 0 to 4000Kg is 20Kg, and the set cutting amount is 4000Kg/min, the accuracy is ±0.5%, but 400Kg/min In the case of , it becomes ±5%, and the cutting accuracy decreases to 1/10.

This means that various powders and granules with different apparent specific gravity (for example, iron-based powder has an apparent specific gravity of 2.
The same is true for transporting pulverized coal (~2.5 and 0.5 for pulverized coal).

Furthermore, since the cutting amount is limited by the nozzle diameter, it is necessary to select the optimal tube diameter for the desired cutting amount.

Therefore, in actual equipment, depending on the demand at the supply end, in some cases, the maximum blowing amount is required at the start of blowing, and the amount is gradually decreased as time passes, or vice versa. could be.

For this reason, the discharging device is required to maintain a constant cutting accuracy regardless of changes in the transport amount.

(Problems to be Solved) The present invention provides a discharge device that can transport from a single pressurized transport tank with constant cutting accuracy for each set transport amount or even if the transport amount changes over time. It is.

(Configuration) The device of the present invention includes a cutting nozzle that opens into one pressurized transport tank, a booster tube connected to the nozzle for cutting out powder and granules from the nozzle, and a load cell that measures the weight of the tank. In the powder transport device, the load cell is equipped with a differentiator that time-differentiates the tank weight loss signal from the load cell, and a mass flow controller that controls the booster gas flow rate based on the output of the differentiator. It is composed of a plurality of different load cells and is equipped with a converter that makes the voltage level the same corresponding to the maximum measurement value of each load cell, and the cutting nozzle is set to a pipe diameter corresponding to the maximum measurement value of each load cell. A plurality of switches are provided, including a switch for switching the output of each of the load cells, a valve opening/closing signal generator for operating the opening/closing valve of each of the cutting nozzles and each of the booster pipes, and a plurality of switches for controlling the adjustment output from the mass flow rate controller. and a selection switch for supplying the booster flow to the booster flow controller of the booster pipe, and sets a desired cutting amount to the mass flow controller, and switches the valve opening/closing signal generator in accordance with the set value. In this way, each load cell output, each cutting nozzle, and each booster tube are selected, and substantially the same cutting precision can be obtained at each set value.

In the present invention, each cutting nozzle is a general term that includes not only the tip of the nozzle but also the portion connected to the transport pipe, and may be connected to a common transport pipe.

(Example) The figure shows an example in which the present invention is applied to a batch type transportation device.

1 is a pressurized transport tank with a supply valve 2 at the top.
A fluidized bed 3 and a fluidized bed chamber 4 are provided at the bottom.

Pressurized gas from a pressurization source (not shown) is supplied to the fluidized bed chamber 4 via a pressure regulating valve 4a, which is connected to a pressure detector 5a and a pressure regulator 5 of the fluidized bed chamber.
The pressure in the tank is adjusted by the output of the tank to maintain a predetermined pressure and to fluidize the powder and granular material in the tank.

6a and 6b are a plurality of cutting nozzles with different diameters having open ends above the fluidized bed, which are selected as the optimum diameter based on the desired cutting setting value.For example, the pipe diameter of 6a is 50φ, and the pipe diameter of 6b is 50φ. It is said to be 25φ.

Reference numerals 7a and 7b are on-off valves provided for each cutting nozzle, and each cutting nozzle is connected to a common transport pipe 8 having a diameter of 60φ, for example. 9 is a connecting portion.

Reference numeral 10 denotes a load cell for measuring the weight of a tank, and includes a plurality of load cells 10a, 10b, and 10c (not shown) adjusted to each maximum value of a plurality of desired cut-out setting values as a measurement full range (rated capacity).
will be adopted.

For example, in the case of three-point support, the strength of each load cell 10 is designed in consideration of the maximum load of all three tanks. 11a, 11b, and 11c are converters for making the voltage level of the output of each load cell constant in the full scale range according to the set cutting amount, and 12 is a changeover switch.

13 is a differentiator for time-differentiating the measurement signal from any selected load cell, and 14 is a mass flow rate controller, which is switched in conjunction with the switch 12 by setting a desired cutting amount.

15a, 15b are respective cutting nozzles 6a, 6b.
A booster pipe connected to a pressurized tank and a common pressurized source.

18a, 18b are on-off valves for each booster pipe, 19
a, 19b are booster flow control valves, 20a, 20b
is a flow rate detector, and 21a and 21b are booster flow rate controllers.

22 is a valve opening/closing signal generator for selecting a cutting nozzle in accordance with the cutting amount setting, that is, the selection of the switch 12, and opening/closing the respective opening/closing valves 7a, 7b and booster opening/closing valves 18a, 18b; This is a selection switch for supplying the control output of the mass flow rate controller to the booster flow rate controllers 21a and 21b in response to the valve opening/closing signal from the valve opening/closing signal generator 22.

Note that the wiring 16 is a signal line for checking the load cell measurement signal at the time of switching each on-off valve.

(Operation method) In the device shown in the figure, the conditions for blowing into the supply end are the maximum blowing amount (transport amount) (L) of the tank at the initial stage.
Kg/min e.g. 4000Kg/min) is required, and in the intermediate period an intermediate amount (MKg/min e.g. 2000Kg/min) is required.
min) is required, and the minimum blowing amount (S
Kg/min (for example, 400 Kg/min), the total transport amount of the cutting nozzles 6a and 6b corresponds to L, the transport amount (optimal output amount) of the cutting nozzle 6a corresponds to M, The transportation amount of the nozzle 6b is S
Assume that it corresponds to In addition, in the load cell 10, the weighing range of 10a is 0 to 4000Kg/min and the minimum weighing unit is 20Kg, and the weighing range of 10b is 0 to 2000Kg/min.
The minimum weighing unit is 10Kg, 10C is 0 to 400Kg/
Assume that min is selected to be 2Kg.

In this case, the weighing accuracy of each load cell is ±
It will be 0.5%. In the figure, first, the setting value of the mass flow rate controller 14 is set to the maximum blowing amount L. Along with this, the switch 12 is switched to the load cell 10a and converter 11a having the maximum measurement range.

Furthermore, the valve opening/closing signal generator 22 is operated to set the opening/closing valves 7a, 7b of the cutting nozzle necessary for the set transport amount L.
and open each of the booster valves 18a and 18b.

The amount of granular material cut out is inversely proportional to the booster flow rate using the tank internal pressure, that is, the pressurized gas supply pressure as a parameter, so if the pressurized tank 1 is in a transportable state, the set value of the booster flow rate controllers 21a and 21b is By supplying the output of the mass flow controller 14, constant flow control is possible.

The amount of cutting from each cutting nozzle is compared by a weight-time differentiator 13 with a set value of a mass flow controller as a tank weight loss per hour, and the difference output is supplied to a booster flow controller.

Thereafter, when the transportation amount set value is changed to M, the switch 12 is switched to the load cell 10b and the converter 11b, and the valve opening/closing signal generator 22 is activated to switch the opening/closing valve 7b of the cutout nozzle 6b and the booster valve 1.
8b is closed, cutting and transportation is carried out exclusively by the nozzle 6a, and the cutting accuracy is ±0.5%.

Next, when the transportation amount set value is changed to S, the switch 12 is switched to the load cell 10c and the converter 11c, and the valve 7a is closed and the valve 7b is opened by the signal from the valve opening/closing signal generator 22, and the booster valve 18
a is closed and valve 18b is opened, and the minimum transport amount is carried out only by nozzle 6b, and the subsequent cutout amount is controlled with the measurement accuracy of load cell 10c, that is, ±0.5%.

(Effects) As described above, according to the present invention, by selecting and combining a plurality of load cells corresponding to a plurality of desired cut-out amounts and a cut-out nozzle that corresponds to the transport amount, each set cut-out amount can be achieved. It becomes possible to maintain approximately the same cutting precision for each amount.

[Brief explanation of the drawing]

The figures are system diagrams of respective embodiments of the device of the present invention. Explanation of drawing symbols 6a and 6b are cutting nozzles,
11a, 11b, 11c are converters that keep the maximum output voltage level of each load cell constant; 12 is a changeover switch; 13 is a weight-time differentiator; 14 is a mass flow controller; 22 is a valve opening/closing signal generator; 24 is a selection Switch.

Claims (1)

[Claims] 1. A cutting nozzle that opens into one pressurized transport tank, a booster pipe that is connected to the nozzle and that cuts out the powder or granular material from the nozzle, a load cell that measures the weight of the tank, and a tank from the load cell. In a powder transport device equipped with a differentiator that time-differentiates a weight loss signal and a mass flow controller that controls booster gas flow rate based on the output of the differentiator, a load cell is connected to a plurality of load cells with different measurement ranges. A plurality of cutout nozzles are provided with pipe diameters corresponding to the maximum measurement value of each load cell,
A switch for switching each of the load cell outputs, a valve opening/closing signal generator for operating the opening/closing valve of each of the cutting nozzles and each booster pipe, and a booster flow rate adjustment of each booster pipe corresponding to the adjustment output from the mass flow controller. and a selection switch for supplying the output to the mass flow rate controller, and by setting a desired output amount in the mass flow controller and switching the valve opening/closing signal generator in accordance with the set value, each of the above-mentioned A powder discharge device characterized in that a load cell output, each cutting nozzle, and each booster tube are selected.