GB2233473A

GB2233473A - Fluidic control devices

Info

Publication number: GB2233473A
Application number: GB9013894A
Authority: GB
Inventors: Stephen Alan Taylor; Lionel Houston Ford
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 1989-06-23
Filing date: 1990-06-21
Publication date: 1991-01-09
Also published as: JPH04500395A; EP0433434A4; FI905016A0; CA2033210A1; GB8914438D0; EP0433434A1; WO1991000388A1; AU6030890A; GB9013894D0; BR9006817A

Abstract

A dewatering system is disclosed in papermaking machine for removing water from a web (P) such as a paper sheet made of pulp. The drainage system includes a vacuum or suction box (1), a separator (3) for separating solids and/or liquids from the drainage, and vortex valve (6) connecting the separator (3) to vacuum (5). Advantageously, the vortex valve (6) operates to maintain a substantially constant pressure at the separator outlet independently of the gas flow through the valve (6).

Description

Improvements in fluidic devices The present invention concerns fluidic control devices known as vortex valves or vortex amplifiers.

A vortex valve or amplifier comprises a vortex chamber through which a main flow passes radially to emerge at an axial outlet, the main flow being regulated by a control flow introduced tangentially into the chamber. An example of a vortex amplifier is found in GB 1,585,519.

In existing forms of vortex amplifiers as depicted in GB Patent Specification 1,585,519 the vortex chamber is formed between two parallel plane surfaces. In situations where the flow through the chamber can contain solid matter it is possible that blockages can occur within the chamber.

According to the present invention there is provided a fluidic control device, in particular a vortex amplifier or vortex valve, comprising a casing formed from abutting releasable parts, at least one of the parts having a substantially conical configuration, a supply fluid inlet communicating with the interior of the casing through a central opening in one of the parts, a fluid outlet shaped as a diffuser communicating with the interior of the casing through a central opening in another of the casing parts, a member within the casing having a configuration corresponding to the conical configuration of the casing part or parts, a surface of the member cooperating with the casing to form a vortex chamber and means for directing a control fluid into the vortex chamber.

The invention will be described further, by way of example, with reference to the accompanying drawings which depict schematically embodiments of vortex amplifiers or vortex valves.

An existing form of vortex amplifier or vortex valve is disclosed in GB 1,585,519 and comprises a casing formed in two abutting parts with a rectangular plate positioned within the casing at a fixed distance from a wall of the casing. The region between the plate and the wall of the casing defines a vortex chamber.

The modified forms of vortex amplifier as illustrated in the accompanying drawings reduce the possibility of blockage within the chamber when the flow therethrough contains solid matter. In the present invention the hitherto flat plate positioned within a casing to define the vortex chamber is replaced by, for example, a cone 1 located within a corresponding casing 2 as shown in Figure 1 or 3. Alternatively the arrangement can comprise a pair of superimposed back-to-back cones 3 within a corresponding casing 4 as in Figure 2. Yet again, as shown in Figure 4, a cylindrical extension can be provided on the cone i, or, as shown in Figure 5, a cylindrical extension can be included between the back-to-back cones 3 in Figure 2.

The casings 2 and 4 can be formed in two abutting parts releasably secured together, for example, by nut and bolt assemblies engaging peripheral flanges on the casing parts. The flow direction through the vortex amplifier is indicated by the arrows, the flow entering at a central inlet 5 in one casing part and exiting at a central outlet 6 which can be a diffuser, that is of increasing cross-section in the direction of flow in another casing part. The cone 1 or cones 3 can be positioned and located within the respective casing 2 and 4 by one or more spacers 7 which also serve for the introduction of a control flow through ports 8. Such a construction is disclosed in GB 1,585,519. Basically, each spacer 7 defines a slot or channel which terminates in a nozzle for the introduction of control flow from the ports 8 into vortex chamber 9.

Flow at the inlet 5 passes over the cone 1 or cones 2 and passes axially and inwardly through vortex chamber 9 to the outlet 6. The flow through the vortex amplifier or valve can be regulated and controlled by means of the control flow at the ports 8 to cause the main flow to spiral through the vortex chamber.

The illustrated embodiments of the invention have circular geometry in planes transverse to the flow direction. This is considered to be the preferred geometry for creating optimum flow conditions within the vortex chamber.

The inclined geometry of the vortex chamber within the casing assists in the flow through the chamber. In particular the inclined geometry can assist in washing down and deters the retention of particles on the surfaces when the flow through the vortex chamber can comprise particulate matter.

Claims

1. A fluidic control device, in particular a vortex amplifier or vortex valve, comprising a casing formed from abutting releasable parts, at least one of the parts having a substantially conical configuration, a supply fluid inlet communicating with the interior of the casing through a central opening in one of the parts, a fluid outlet shaped as a diffuser communicating with the interior of the casing through a central opening in another of the casing parts, a member within the casing having a configuration corresponding to the conical configuration of the casing part or parts, a surface of the member cooperating with the casing to form a vortex chamber and means for directing a control fluid into the vortex chamber.

2. A fluidic control device as claimed in Claim 1 in which the means for directing control fluid into the chamber comprises one or more spacers for positioning and locating the member within the casing, the or each spacer having a slot or channel terminating in a nozzle for the introduction of control fluid into the vortex chamber.

3. A fluidic control device, in particular a vortex amplifier or vortex valve substantially as herein described with reference to and as illustrated in any one of the accompanying drawings.