JPS61206715A - Screw feeder for feeding powder with pressure - Google Patents

Abstract

PURPOSE:To mix powder in a stable state in a pressurized fluid by fixed quantity by introducing a pressurized fluid increasing in pressure sequentially from each gas introduction port into a cylindrical casing, and from a powder supply port to a discharge port. CONSTITUTION:A screw feeder comprises a cylindrical casing 1 having a power supply port 2 at one end thereof and a discharge port 4 connected to a transfer path 3 for a pressurized fluid at the other end portion thereof, a screw blade 6 rotatably disposed in the casing 1, and a rotation driving device for rotating the blade 6. The outside diameter of the blade 6 is gradually reduced from one end side to the other end side, and the casing 1 is provided with a plurality of gas introduction ports 7A-7E disposed along the axis thereof. Gas introduction paths 10A-10E for introducing a part of the above pressurized gas are provided at the respective gas introduction ports. Further, pressure reducing valves 11A-11E are respectively interposed in the gas introduction paths, and the set pressure of these pressure reducing valves is gradually decreased from the other end side to one end side.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a screw feeder for pumping powder for supplying a fixed amount of powder into pressurized gas.

BACKGROUND ART Conventionally, for the purpose of using coal in a gas turbine, there is a screw feeder that continuously and quantitatively supplies powder (an example of powder) to pressurized gas (air or gas).

Problems to be Solved by the Invention By the way, according to the conventional screw feeder, the pitch and diameter of the screw blades for transporting pulverized coal are all equal, and the pressure inside the cylindrical casing is not controlled. It was not possible to provide a stable supply of pulverized coal.

Therefore, an object of the present invention is to provide a powder-pumping screw feeder that can solve the above-mentioned problems.

Means for Solving the Problems In order to solve the above problems, the screw feeder for pumping powder of the present invention has a powder supply port on one end side and communicates with a pressurized gas transfer path on the other end side. In a screw feeder consisting of a cylindrical casing having a discharge port, a screw blade rotatably disposed within the cylindrical casing, and a rotary drive device that rotationally drives the screw blade, the blade outer diameter of the screw blade is A plurality of gas inlet ports are provided in the cylinder upper casing along the axis of the cylinder upper casing, gradually decreasing in size from one end side to the other end side, and a part of the pressurized gas is introduced into each of these gas inlet ports. A pressure reducing valve is provided in each of these gas introducing paths, and the set pressure of these pressure reducing valves is sequentially decreased from the other end toward the one end.

Effect: Therefore, when powder is supplied into the powder supply port while pressurized fluid is flowing through the transfer path, it is sequentially compressed and moved toward the discharge port by the rotating screw blades, and is then transferred from the discharge port. A fixed amount is supplied into the transfer pipe. Further, at this time, pressurized gas is sequentially introduced from each gas inlet into the cylindrical casing in a pressurized state from the powder supply port toward the discharge port side.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. 1 has a pulverized coal supply port 2 at one end, and a pressurized coal supply port 2 at the other end (
It is a cylindrical casing having a discharge port 4 communicating with a transfer pipe 3 (air or gas), and its inner diameter gradually decreases from one end to the other end. Incidentally, flanges 5A and 5B are provided at the upper and lower ends of the transfer pipe 3 so as to be interposed in the transfer path of the pressurized gas. Reference numeral 6 denotes a screw blade rotatably disposed within the cylindrical casing 1. The outer diameter of the blade portion 6a is gradually decreased from one end to the other end, and the outer diameter of the rotating shaft portion 6b is also decreased from one end to the other. It is made to gradually become smaller toward the other end.

In addition, from the convergence angle θ1 of the outer diameter of the blade portion 6a, the rotating shaft portion 6b
The convergence angle θ2 of the outer diameter is made larger. Further, the convergence angle of the cylindrical casing 1 is matched to the convergence angle of the blade portion 6a. Therefore, each blade portion 5a,
The volume between 6a is gradually reduced from one end side to the other end side. A plurality of numbers 7A to 7E are provided along the axis of the cylindrical casing 1 (in this embodiment, there are five pieces, depending on the number of turns of the screw blade, but the number is not limited to this number).
Pressurized gas is supplied to each of the provided gas inlet ports, and the pressure decreases sequentially from the other end toward the one end. That is, the transfer pipe 3 is provided with an outlet 8 for pressurized gas, and a main gas introduction pipe 9 is connected to this outlet 8, and the main gas introduction pipe 9 is connected to each of the gas introduction lowers A mentioned above. ~ Sub-gas introduction pipe 1 connected to 7E
0A to IOE are connected, and furthermore, pressure reducing valves 11A to 11E are interposed at positions upstream from the connection points of each sub gas introduction pipe 10A to IOE of the main gas introduction pipe 9, and each gas introduction lower A to The gas pressures P1 to P5 introduced into 7E are:
The relationship is as shown in equation 0.

Pa <P5 <Pl <P3 <P2 <Pl <P
G -... ■■ In the formula, Pa - Atmospheric pressure Po - Pressure of pressurized gas Note that although not shown, the rotation axis 6 of the screw blade 6
A rotary drive device @ (for example, an electric motor) is connected to the end flange 6C of b.

Therefore, when pulverized coal B is supplied into the pulverized coal supply port 2 while the pressurized fluid A is flowing through the transfer pipe 3, it is sequentially compressed and moved toward the discharge port 4 by the rotating screw blades 6. A fixed amount is supplied from the discharge port 4 into the transfer pipe 3 at a time. Further, at this time, pressurized gas is sequentially introduced into the cylindrical casing 1 from each of the gas introduction lowers A to 7E in a pressurized state from the pulverized coal supply port 2 toward the discharge port 4 side.

In addition, in the above-mentioned example, powdered coal was explained as powder, but it is not limited to this.

Effects of the Invention According to the above configuration of the present invention, by gradually decreasing the outer diameter of the screw blade toward the discharge port side, the powder is compressed and moved from the powder supply port side to the discharge port side. Therefore, it is possible to control the pressurized fluid from flowing back toward the powder supply port, and the pressure is increased sequentially from each gas inlet into the cylindrical casing and from the powder supply port to the discharge port. By introducing the pressurized fluid into the pressurized fluid, the pressure state during the movement of the powder can be made steady and the rate of pressure rise can be made uniform. Therefore, the powder can be quantitatively and stably added to the pressurized fluid. It can be mixed in the same state.

[Brief explanation of drawings]

The drawing is a sectional view of one embodiment of the present invention.

Claims (1)

[Claims] 1. A cylindrical casing having a powder supply port at one end and a discharge port communicating with a pressurized gas transfer path at the other end; a screw blade rotatably disposed within the cylindrical casing; In a screw feeder comprising a rotary drive device that rotationally drives the screw blade, the blade outer diameter of the screw blade is gradually reduced from one end side to the other end side, and a gas inlet is provided in the cylindrical casing above the cylinder. A plurality of gas introduction ports are provided along the axis of the casing, and each of these gas introduction ports is provided with a gas introduction path for guiding a portion of the pressurized gas, and a pressure reducing valve is interposed in each of these gas introduction paths, and these pressure reducing valves are A screw feeder for force-feeding powder, characterized in that the set pressure of is gradually decreased from the other end toward the one end.