GB2172272A

GB2172272A - Solid fuel transfer and seal system

Info

Publication number: GB2172272A
Application number: GB08605796A
Authority: GB
Inventors: Justin P Winkin
Original assignee: Foster Wheeler Energy Corp
Current assignee: Foster Wheeler Energy Corp
Priority date: 1985-03-11
Filing date: 1986-03-10
Publication date: 1986-09-17
Also published as: GB8605796D0; JPH0240931B2; JPS61246517A; ES8701668A1; ES552742A0; GB2172272B; CA1269891A

Abstract

A solid fuel transfer and seal system in which a seal chamber receives a fuel material and a valve 30 is provided for opening and closing a discharge opening 14B in the seal chamber 14. A seal plug unit 22 moves across the chamber to push the fuel material contained in said chamber towards the discharge opening. The valve 30 is opened in response to a predetermined amount of movement of the seal plug unit 22 towards the discharge opening, e.g. as determined by limit switch 40, and the seal plug unit seals the inlet opening 14A from the discharge opening after opening of the valve. A level limit switch or metering device associated with inlet conveyor 24 or chute 26 measures the amount of fuel in chamber 14 and triggers movement of unit 22; further limit switches 42 and 44 define its limits of travel. <IMAGE>

Description

SPECIFICATION Solid fuel transfer and seal system This invention relates to a solids fuel transfer and seal system and, more particularly, to such a system for metering a precise amount of fuel between a source and a furnace, or the like, while positively sealing against atmospheric pressure.

In large furnaces such as, for example, those associated with a steam generator, or the like, a large number of burners extend around the furnace and are fed fuel, such as coal material, from a single source. In these type of arrangements, it is difficult to exactly meter a precise amount of coal to each burner, and in addition, seal against atmospheric pressure, i.e. tramp air. Although various techniques have been devised, none has proven to be absolutely satisfactory from both a precise metering standpoint and a seal standpoint.

The present invention provides a solid fuel transfer and seal system comprising a source of solid fuel material, a seal chamber having an inlet opening for receiving said fuel material and a discharge opening disposed at one end of said chamber, valve means for opening and closing said discharge opening, a seal plug unit disposed at the other end of said chamber, and defining a wall of said chamber, said seal plug unit being moveable across said chamber to push towards said discharge end the fuel material contained in said chamber between said inlet opening, said discharge opening and said seal plug unit, and means responsive to a predetermined amount of movement of said seal unit towards said discharge opening for opening said valve means, said seal plug unit sealing said inlet opening from said discharge opening during and after opening of said valve means.

The solid fuel transfer and seal system of the invention allows a precise amount of fuel to be metered from a source and transferred to the burners in the furnace and seal against atmospheric pressure. The system of the present invention is simple in operation, efficient in use and relatively inexpensive in cost.

The invention will now be described with reference to the accompanying drawing which represents a cross-sectional view depicting the fuel transfer and seal system of the present invention.

The reference numeral 10 refers in general to a housing configured to form an inlet conveying chamber 12, a storage and sealing chamber 14 and an outlet conveying chamber 16. A runway 18 is supported on the floor 20 of the housing 10 and received a seal plug unit 22 which traverses the runway in a manner to be described.

An endless loop conveyor belt 24 extends into the inlet conveying chamber 12 and has an inlet end portion 24A disposed adjacent the housing 10, and a discharge end portion 24B disposed in the chamber 12. The conveyor belt 24 receives the solid material to be conveyed, such as coal, from a source, via a chute 26, and conveys the material in a horizontal direction through the chamber 12.The material discharges off the discharge end 24B of the conveyor 24 and downwardly by gravity through an inlet opening 14A of the chamber 14 and irito the latter chamber, as shown by the arrows: The chamber 14 has a discharge end 14B over which is mounted a discharge valve, or gate 30 pivotally mounted on a top shaft, or hinge 32 and adapted to be moved in a conventional manner between a closed position shown by the solid lines to an open position shown by the dashed lines, to respectively close and open the discharge end 14B.

An inclined conveyor belt 34 is disposed in the chamber 16 and together with a portion of the housing 10, defines a hopper 36 for receiving the material to be transferred from the chamber 14, as will be described. The conveyor belt 34 has a lower, inlet end portion 34a adjacent the hopper 36 and an upper discharge end portion 34b. The material thus travels through the chamber 16, via the conveyor belt 34, before discharging by gravity, via a discharge chute 38 registering with the chamber 14, to a furnace, or the like (not shown).

The seal plug unit 22 is shown in its inactive position in the drawings in which its leading end portion 22A defines one end of the chamber 14. The unit 22 is adapted to move in a direction from right-to-left, as viewed in the drawing, towards the discharge opening 148, as well in a reverse direction, and its movement, as well as movement of the valve 30, is controlled by a three limit switch 40, 42 and 44 associated with the runway 18, which respond to the location of the unit on the runway, as will be described. It is understood that the seal plug unit 22 and the valve 30 can be powered in any conventional manner and, for the purpose of example, are operted pneumatically.

In operation, a solid particulate or shredded fuel material is conveyed onto the upper surface of the inlet end portion 24A of the conveyor 24, via the discharge chute 26. The material traverses the length of the conveyor 24 before falling off the discharge end 24B by gravity. The fuel material then passes through the inlet opening 14a of the chamber 14 where it accumulates in the space betwen the valve 30 and the end portion 22A of the seal plug unit 22.

A level limit switch or metering device (not shown) associated with the conveyor belt 24, or the shute 26, provides a signal when a predetermined amount of fuel material has accumulated for actuating the seal plug unit 22.

This causes the unit 22 to traverse the run way 18 in a direction from right-to-left as viewed in the drawing, whereby it pushes the amount of fuel material accumulating in the chamber 14 towards the discharge opening 14B. The seal plug unit 22 continues movement until it spans the opening 14A, after which time the limit switch 40 actuates the valve 30 to its open position shown by the dashed lines. This enables the metered amount of fuel material to discharge by gravity into the hopper 36. The conveyor belt 34 then transfers the metered amount of fuel in the hopper 36 to the chute 38 from which it is introduced to the furnace.

The seal plug unit 22 continues its forward movement until its forward end extends a short distance past discharge opening 14B at which time the second limit switch 42 terminates further movement of the unit in the forward direction, initiates a slight pause, and then reverses movement of the unit towards its inactive position. During this return movement the limit switch 40 initiates closing of the valve 30 when the unit spans the opening 14A, and the limit switch 44 stops the reverse movement and transfers the operation back to the level limit or metering switches. It is understood that the entire circuitry just described can be incorporated and sequenced into a fuel feed system and boiler master control to further control the operation of the sytem of the present invention in accordance with fuel supply and demand needs.

As the plug unit 22 travels by and spans the inlet opening 14A it achieves a positive seal between the atmosphere and the hopper 26 to prevent the introduction of atmospheric air, i.e. tramp air, into the latter hopper. Also, by virtue of the system of the present invention, a precise amount of fuel material is metered from the chute 26 to the hopper 26 and, from the latter to the discharge chute 38.

Also, in the movement of the seal plug unit 22, the dishcarge gate is opened and closed while the unit 22 is spanning the opening 14a to ensure continuity of the afore-mentioned seal.

It is thus seen that the fuel transfer and seal system of the present invention provides an efficient and simple operation at a relatively low cost while achieving the afore-mentioned advantages.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

Claims

1. A solid fuel transfer and seal system comprising a source of solid fuel material, a seal chamber having an inlet opening for receiving said fuel material and a discharge opening disposed at one end of said chamber, valve means for opening and closing said discharge opening, a seal plug unit disposed at the other end of said chamber, and defining a wall of said chamber, said seal plug unit being moveable across said chamber to push towards said discharge end the fuel material contained in said chamber between said inlet opening, said discharge opening and said seal plug unit, and means responsive to a predetermined amount of movement of said seal unit towards said discharge opening for opening said valve means, said seal plug unit sealing said inlet opening from said discharge opening during and after opening of said valve means.

2. A system of Claim 1 further comprising conveyor means for receiving said fuel material from a source of material and discharging said fuel material to said inlet opening.

3. The system of Claim 1 further comprising means for forming a hopper communicating with said discharge opening, and conveyor means for transferring said fuel material from said hopper means to a discharge chute.

4. The system of Claim 1 further comprising means responsive to said seal plug unit reaching said discharge end for reversing the movement of said seal plug unit away from said discharge end and towards said resting position.

5. The system of Claim 4 further comprising means responsive to a predetermined amount of movement of said seal plug unit towards said resting position for closing said valve means.

6. The system of Claim 5 wherein said seal plug unit seals said inlet opening until said valve means is closed.

7. A solid fuel transfer and seal system substantially as herein described with reference to the accompanying drawings.