GB2059040A - Control valves for regenerative and other ventilation systems - Google Patents

Abstract

A valve for controlling the flow of air in a ventilation system comprises plates (1, 2) in face-to-face engagement with other members (3, 4) and each slidable with respect to their corresponding member between two set positions. Each plate has a plurality of openings (5) through it and the corresponding other member has first and second sets of openings (7 and 8) that are aligned with the openings through the plate in its respective set positions. Partitions segregrate air flowing through the openings of the respective sets. An important application is a double cross-over valve for switching flow of inward and outward air streams to flow alternately through a pair of heat storage devices in a regenerative ventilation system. <IMAGE>

Description

SPECIFICATION Control valves for regenerative and other ventilation systems This invention relates to valves for controlling the flow of air in ventilation systems, and more specifically to two-way and cross-over valves for diverting or reversing the flow of air.

An important application of the invention is in the control of regenerative heat-recovery systems of the kind in which outgoing air flows through a (first) heat-store device to raise its temperature (or cool it in the case of an air-conditioned system cooled below ambient temperature), after which the outgoing air is diverted to a second heat-store device and incoming air drawn through the first heatstorage device to recover heat from it (or in the alternative case to be cooled by it).

Flap valves (dampers) can be used for this purpose, but they require relatively large movements and to cannot be switched quickly without requiring appreciable power and risking unwelcome noise. Conventional slide valves operating on the hit-and-miss principle would avoid these drawbacks but are often ruled out by the space required (over four times the flow area for a simple two-way operation), or by non-uniformity of flow.

The valve in accordance with the invention comprises a plate in face-to-face engagement with another member (preferably another plate) and slidable with respect to it between two set positions. The plate has a plurality of openings through it, the other member has a first series of openings that are aligned with openings through the plate in one set position and a second series of openings that are aligned in the other set position with the same plate openings. Partitions segregate air flowing through the openings of the respective sets.

Preferably all the openings are slots extending transversely with respect to the direction of sliding movement, of any convenient length and with a width just less than the distance of travel of the plate between its set positions; in this way a two-way valve is provided in an area little more than twice the flow area provided. Three (or more) ways could be provided, if required, by providing three (or more) series of apertures in the second member of the valve and appropriate partitions.

To perform more complex airflow switching operations, the plate may have two or more groups of openings each with two (or more) properly related and partitioned openings in the second member.

In particular, a preferred form of the invention is a cross-over valve connecting four ducts (ducts A, B, C and D) so as to connect ducts A and C together and B and D together in one of the set positions of the plate and ducts A and D together and ducts B and C together in the other.

In one such cross-over valve, there are two slidable plates, one plate on each side of a median partition that extends in the direction of sliding, separating two ducts. Each plate has slots which all extend transversely to the direction of sliding. The first series of openings in each second member corresponding to a plate communicates directly with a respective space separated from the corresponding space for the second series by a further median partition.

In another such valve, a single plate has two groups of openings formed by slots, one group on each side of a median partition that extends in the direction of sliding. The slots all extend transversely to the direction of sliding, and the slots of the two groups are staggered. The first series of openings in the second member, for each of the groups, communicates directly with a respective space separated from the corresponding space for the other group by a further median partition; and the second series of openings for each group is connected by ducts to the other side of the further median partition.

Two cross-over valves can be combined into a single unit so that duct A leads always to duct Al, but in one position via duct C and the other via duct D, while duct B leads always to duct B' but in the first position via duct D and the second via duct C. Ducts C and D may contain heat-storage units, for instance. In some such cases it will be preferable, if other requirements permit, to arrange that the first position of one of the valves corresponds to the second position of the other, as the flow impedance may then be substantially the same in both positions of the valve.

Thus the invention includes a regenerative heat recovery and ventilation system comprising two heat-storage devices, a first pair of ducts and a second pair of ducts, and two cross-over valves for connecting either the first or the second heat-storage device between the ducts of the first pair and the other heatstorage device between the ducts of the second pair, each of the cross-over valves being of the preferred form described. A single plate could be common to both of them if desired.

In order that the invention may more readily be understood, a description is now given, by way of example only, reference being made to the accompanying drawings, in which: Figure 1 is a cut-away perspective view of a section of a double cross-over valve in accordance with the invention; Figures 2A and B are diagrammatic crosssections of a regenerative heat exchanger installation in accordance with the invention incorporating two similar valves, shown with the valves in different set positions; Figure 3A and 3B are partial diagrammatic views of a particular form of valve in the respective set positions; Figure 4 is a cut-away perspective view of another heat exchanger installation using other valves in accordance with the invention.

In the valve of Fig. 1, each duct A and B has a plate 1, 2 respectively which is slidable relative to a grille 3, 4 respectively between two set positions, each of which provides the alignment of openings in the plates formed by slots 5 and 6 respectively (shown only for ease of recognition as having rounded ends) with one or other of two series of openings 7 and 8 in the grilles. These openings 7 and 8 are in the form of slots extending transversely of the direction of sliding S. On the side of each grille away from the plate, the two series of openings 7 and 8 are separated by septa 9, 10, 11, 1 2 (some being shown cutaway for clarity).

Thus, when the slidable plates are in the position shown in Fig. 1, the first series of slots 7 of grille 3 is blocked by plate 1, but the second series of slots 8 align with slots 5 so that duct A communicates, via a chamber formed between septa 10 and 11 and an aperture 13, with the duct C. Similarly, duct B is in communication with duct D via a chamber formed between septa 9 and 10 and aperture 14.

A regenerative heat exchanger installation incorporating two such valves is shown in true cross-section in Figs. 2A and B, the plane of section corresponding with the plane ll-ll in Fig. 1. In this unit, intake duct A leads always to duct A1 but in one of the set positions of the slidable plates via duct C containing heat exchange medium 1 5 and in the other set position via duct D containing heat exchange medium 1 6. Similarly, exhaust duct B, leads always to duct B, but via duct D in the first set position of the slidable plates, as in Fig.

2A and via duct C in the second set position as shown in Fig. 2B.

If AA' and B'B are respectively the exhaust and inlet ducts of a ventilation system, then, with the plates in the position corresponding to Fig. 2A, the exhaust stream gives up heat to heat exchange medium 16, whilst the inlet stream takes up heat from heat exchange medium 1 6. When the plates are switched to the position corresponding to Fig. 2B, the stream passing through each heat exchange medium is changed so that the exhaust stream now gives up heat to medium 16, whilst the inlet stream now takes up heat from medium 1 5.

Figs. 3A and 3B illustrate the plate and grille arrangements (in the set positions of Figs. 2A and 2B respectively) from the duct side for grilles 3, 4 each with six slots and a particular form of plate 1, 2 with two slots.

Such a plate does not extend beyond the edges of the grille in either of its set positions thereby permitting the plate to be wholly contained at all times within its duct. Moreover, with suitable mechanical linkage the plates can be readily moved to ensure that at no time during operation of the installation are the plates in the same set position. Generally, for a grille with 2n slots, the corresponding plate of this type has (n-1) slots.

The regenerative heat exchanger of Fig. 4 incorporates a different form of valve embodying the present invention, the same references being used for corresponding parts.

In this installation the two pairs of ducts AA' and BB1 share a single slidable plate 1 7 having two groups of openings (one for each pair of ducts) formed by slots 18, one group on each side of a septum 1 9 which extends in direction of sliding S, the slots of the two groups being staggered. Also the two pairs of ducts share a single grille 20 having, on each side of septum 19, a first series of openings formed by slots 21 which communicate directly with the duct vertically above, and a second series with slots 22 which communicate with tunnels 23 each of which leads through an aperture 24 in septum 19 to the duct on the other side. The tunnels of the two pairs of ducts are staggered.

Thus in the set position shown in Fig. 4, slots 1 8 communicate with slots 21 permitting flow from duct A to pass upward through duct C, over a wall 25 and downwardly via slots 21 on the other side of a wall 25 to duct A'; similarly flow from duct B' passes through duct D to duct B.

In the other set position, slots 1 8 communicate with slots 22, so that flow from duct A passes along tunnels 23, through apertures 24 and into duct D; it then passes over wall 25 and through apertures 24, tunnels 23 and slots 22 on the other side of wall 25 and into duct A'. Flow from duct B1 to B follows a corresponding path through the tunnels 23 and apertures 24 on the other side of septum 19.

If AA' and B'B are respectively the exhaust and inlet ducts of a ventilation system, then, with the plate 1 7 in the position shown in Fig. 4, the exhaust stream gives up heat to the two sections of heat exchange medium 1 5 contained in duct C, whilst the inlet stream takes up heat from the two sections of heat exchange medium 1 6 contained in duct D.

When plate 1 7 is moved to the second set position, so that duct A is now connected to duct A' via duct D, and duct B' is connected to duct B via duct C, the stream passing through each heat exchange medium is changed so that the exhaust stream now gives up heat to the two sections of heat exchange medium 1 6 contained in duct D, whilst the inlet stream takes up heat from the two sections of heat exchange medium 1 5 contained in duct C.

Each form of regenerator may achieve high efficiencies of heat recovery, comparable to those attainable with rotary regenerators, by repetitive switching of the plate(s) with a period determined by the required efficiency, the mass flow rate of air, and the heat storage capacity of the heat exchange media. The switching time should be very short compared with the intervals between switching. This repetitive switching can be carried out by any suitable mechanism for converting rotary motion into intermittent reciprocating motion, so that the plates can then be driven by an electric motor, or, alternatively, they can be driven by electrically operated solenoids, actuated by a suitable timing device.

Claims (7)

1. A valve for controlling the flow of air in a ventilation system comprising: a plate in face-to-face engagement with another member and slidable with respect to it between two set positions, the plate having a plurality of openings through it; the other member having a first series of openings that are aligned with openings through the plate in one set position and a second series of openings that are aligned in the other set position with the same plate openings; and partitions to segregate air flowing through the respective series of openings.

2. A cross-over valve for controlling the flow of air in a ventilation system comprising: two plates, each plate in face-to-face engagement with a corresponding member and slidable with respect to it between two set positions, one plate on each side of a median partition that extends in the direction of sliding, each plate having openings formed by the slots extending transversely to the direction of sliding; each member having a first series of openings that are aligned with openings through the plate in one set position, and a second series of openings that are aligned in the other set position with the same plate openings; and partitions to segregate air flowing through the respective series of openings and to lead (i) from the first series of openings for each member into a respective space separated from the corresponding space for the other member by a further median partition and (ii) from the second series of openings of each member by ducts to the other side of the further median partition.

3. A cross-over valve according to Claim 2 wherein the two plates are integral with each other.

4. A regenerative heat recovery and ventilation system comprising two heat-storage devices, a first pair of ducts and a second pair of ducts, and two cross-over valves for connecting either the first or the second heat-storage device between the ducts of the first pair and the other heat-storage device between the ducts of the second pair, each of the crossover valves comprising: two plates, each plate in face-to-face engagement with a corresponding member and slidable with respect to it between two set positions, one plate on each side of a median partition that extends in the direction of sliding, each plate having openings formed by slots extending transversely to the direction of sliding; each member having a first series of openings that are aligned with openings through the plate in one set position and a second series of openings that are aligned in the other set position with the same plate openings; and partitions to segregate air flowing through the respective series of openings and to lead (i) from the first series of openings for each member into a repective space separated from the corresponding space for the other member by a further median partition and (ii) from the second series of openings of each member by ducts to the other side of the further median partition.

5. A system according to Claim 4, wherein a single plate is common to both cross-over valves and has two staggered groups of slots, one group on each side of the median partition.

6. A double cross-over valve substantially as hereinbefore described with reference to and as illustrated in Figs. 1, and/or 2A and 2B, and/or 3A and 3B or in Fig. 4 of the accompanying drawings.

7. A regenerative heat-recovery and ventilation system substantially as described with reference to and illustrated in Figs. 1, and/or 2A and 2B and/or 3A and 3B or in Fig. 4 of the accompanying drawings.