GB2129395A

GB2129395A - Rotary air lock valve

Info

Publication number: GB2129395A
Application number: GB08327365A
Authority: GB
Inventors: John Arthur Burton
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-11-01
Filing date: 1983-10-13
Publication date: 1984-05-16
Also published as: GB8327365D0

Abstract

A rotary air lock valve comprises a shaft 12 carrying radial vanes 13 rotatable within a cylindrical chamber 11 having an inlet opening 14 and an outlet opening 15 and a duct 17 for supply of pressure air to assist discharge of material through the outlet opening. The pressure air duct 17 enters the chamber axially through an end plate and the outlet 15 exits the chamber substantially tangentially at right angles to the pressure air duct such that there is no direct through passage for the pressure air. <IMAGE>

Description

SPECIFICATION Rotary air lock valve This invention concerns a rotary air lock valve of the kind (herinafter termed 'of the kind referred to') comprising a cylindrical chamber having a rotatable shaft extending axially therethrough and carrying a plurality of radially extending vanes whose outer axially extending edges make sealing contact with the inner surface of the cylindrical wall of the chamber, an inlet opening through the cylindrical wall of the chamber for admitting divided solid material to the spaces between the vanes and an outlet opening on the side of the chamber opposite the inlet opening for discharge of said material and a conduit for the supply of air under pressure to the interior of the chamber to entrain said solid material and assist its discharge through said outlet opening, the arrangement of openings and vanes being such that there is never a direct connection between the inlet opening on the one hand and the conduit and outlet opening on the other hand, so that the valve acts as an air lock.

Conventionally the conduit and outlet opening have been located opposite one another in the opposed ends of the chamber at a position generally diametrally opposite the inlet opening.

Tests have shown, with such conventional arrangement, that the pressure air tends to clear a passage and leave much of the solid material to be recycled.

It is an object of the present invention to provide an improved arrangement ensuring more complete discharge thus enabling greater throughput.

According to the present invention there is provided a rotary air lock valve of the kind referred to wherein said conduit for pressure air enters the chamber in a substantially axial direction through an end plate thereto and wherein said outlet exits the chamber substantially tangentially with respect to the cylindrical wall and at right angles to the direction of air supply.

Preferably the outlet comprises a plurality of axially linearly spaced ducts each communicating with the interior of the chamber tangentially or substantially so.

By this means, there can be no direct throughpassage for the pressure air, and considerable turbulence is created ensuring more complete entrainment of the solid material, effective discharge and greater throughput thereof.

The invention will be further apparent from the following description, with reference to the figures of the accompanying drawings, which show, by way of example only, one form of rotary air lock valve embodying the invention.

Of the drawings: Figure 1 shows a cross-section through the valve; Figure 2 is a part sectional eievation of the air lock valve viewed in the direction of Arrow II of Figure 1; and Figure 3 is a cross-section through the rotary part of the valve showing the construction thereof in greater detail.

The rotary air lock valve illustrated in Figures 1 and 2 comprises a cylindrical chamber 11 having a rotatable shaft 12 extending axially through the chamber 11 and carrying six radially extending vanes 1 3 whose outer axially-extending edges 1 3a make sealing contact with the inner surface 11 a of the cylindrical wall of the chamber 11. An inlet opening 14 is provided for admitting divided solid material to the spaces between the vanes 13.

A plurality of outlet openings 1 5 (in this example three) are provided in the cylindrical wall of the chamber 11, spaced circumferentially from the inlet opening 14, for discharge of said divided solid material into outlet ducts 1 6.

A conduit 1 7 is provided for the supply of air under pressure to the interior of the chamber 11 to entrain said solid material and assist its discharge through the outlet openings 15.

The arrangement of openings 14, 1 5 and 1 7 and vanes 1 3 is such that there is never a direct connection between the inlet opening 14 and the conduit 17 nor between the inlet opening 14 and the outlet openings 15, so that the valve acts in the fashion of an air lodk.

The conduit 17 for pressure air enters the chamber 11 in a substantially axial direction through an end plate 1 h of the chamber 1 The outlet ducts 16 leave the chamber 11 substantially tangentially of the cylindrical wall thereof and at right angles to the direction of the pressure air supply.

It will be seen that there is no direct through passage for the pressure air, and that considerable turbulence will be created ensuring more complete entrainment of the solid material and effective discharge and greater throughput thereof.

Referring now to Figure 3 it will be seen that the vanes 13 are keyed to the shaft 12 in milled, lengthwise-extending slots 20 for circumferential location.

The vanes 13 are held against radial movement by wedges 21 acting between adjacent vanes 1 3 and releasably attached to the shaft 1 2 by screws, for instance, Allen screws 22 engaging in radially directed threaded bores 23 in the shaft 1 2.

The wedges 21 comprise sectors of a cylinder.

The edges 1 3a of the metal vanes 1 3 have rubber or like material, edgewise-disposed seals 24 vulcanised or otherwise bonded to the metal for effective air sealing. When such seals wear through contact with the inner wall of the chamber 11 and abrasion by particulate materials being metered, the vanes 1 3 are simply removed by releasing the Allen screws 22 and removing the wedges. New vanes are substituted, the old ones being if desired repaired by removing the old seals and bonding new ones in their place. This latter operation of course, does not contribute to downtime of machinery or plant incorporating the valve, and the replacement of worn vanes is a very much easier and less time-consuming task than the replacement of seals in situ.

In an alternative arrangement the vanes may be secured to the shaft by spot welds. The user then replaces the entire rotor assembly and discards the old or returns it for repair.

It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof as defined by the

Claims

appended claims. CLAIMS

1. A rotary air lock valve of the kind referred to wherein said conduit for pressure air enters the chamber in a substantially axial direction through an end plate thereto and wherein said outlet exits the chamber substantially tangentially with respect to the cylindrical wall and at right angles to the direction of air supply.

2. A rotary air lock valve according to claim 1, wherein said outlet comprises a plurality of axially linearly spaced ducts each communicating with the interior of the chamber tangentially or substantially so.

3. A rotary air lock valve according to claim 2, wherin there are three said ducts.

4. A rotary air lock valve according to any prceding claim, wherein the vanes are of metal and have rubber or like material edgewise disposed seals which are vulcanised or otherwise bonded to the metal.

5. A rotary air lock valve according to any preceding claim, wherein the vanes are keyed to the rotatable shaft for circumferential location and held against radial movement by wedges acting between adjacent vanes and releasably attached to the shaft.

6. A rotary air lock valve according to claim 5, wherein said wedges are releasably attached to the shaft by screws engaging radially threaded bores in the shaft.

7. A rotary air lock valve substantially as described herein with reference to and as illustrated by the figures of the accompanying drawings.