GB1560033A - Gas flow regulating structure - Google Patents

Description

(54) GAS FLOW REGULATING STRUCTURE (71) We, HALTON Oy, a Finnish Company of 47400 Kausala, Finland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to structures for controlling gas flow.

The present invention concerns in par circular a control structure comprising a plurality of throttling blades which overlap each other.

Various types of controls are Ipresently utilized for purposes such as air-flow measurement and control of the air intake and exhaust duct systems of air conditioning installations. The simplest known control means of :this type is a control damper disposed within a duct. This damper may be turned so as to control the cross-section through which the gas is permitted to flow, so that in this way it is possible to change the volume of gas which flows through the duct. One of the primary drawbacks of this type of control structure resides in the fact mat the adjustment thereof changes the direction of gas flow.

There are also known gas4iow controlling structures in the form d iris units having throttling blades which are situated in a plane normal to the axis of the duct, these blades being movable in the latter plane.

However, a control structure of this type is relatively expensive as a result of the high manufacturing and installation oosts thereof.

In addition, the range of control which can be achieved with such a construction is limited inasmuch as the maximum flow aperture of such a construction is substantially smaller than the cross-section of the hollow interior of the duct.

What is desired is a gas-flow control structure which will avoid the drawbacks of the above known structures, which is relatively inexpensive to manufacture and mount, which can be situated in the interior of the duct in such a way that the crosssection of the path d gas flow when the structure provides the minimum throttling action is substantially equal to the crosssection of the hollow interior of the duct, which is capable of distributing the gas flow uniformly with respect to the duct axis in all adjusted positions of the structure without changing the direction of gas flow when the structure is adjusted to change the extent to which the gas flow is throttled, and which can easily be provided with thermal lagging or insulation to avoid fire hazards.

The present invention provides a structure for controlling the flow of gas comprising, duct means through which the gas is to flow, the duct means having a predetermined axis, circular ring means situated in the duct means between opposed ends thereof and coaxially surrounding the said axis and being situated in a plane normal to the said axis, and a Iplurality of throttling blades overlapping each other and distri- buted around withe said axis and along the ring means, the blades defining the side surface ,of a truncated cone whose axis coincides with the said predetermined axis, the blades having upstream ends defining the base of the truncated cone and downstream ends defining the apex of the truncated cone, and the ring means supporting said blades for pivotal movement around the ring means for adjusting the inclination of the blades relative to the said axis and thus the size of the apex to control the size of the aperture defined by the downstream ends of the blades through which aperture the gas in the duct means flows, so that the flow of air through the duct can be regulated by situating the blades at a selected inclination, the side edge portions of the blades overlapping to such an extent that they remain overlapping along their entire length during adjustment of the inclination.

The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic elevation of a structure for controlling the flow of gas, taken in a plane normal to the duct axis and showing the structure fragmentarily when looking toward the throttling aperture of the structure; Figure 2 is a schematic illustration of the manner in which the structure can be adjusted for controlling the throttling aperture; Figure 3 illustrates one d the overlapping throttling blades of the structure; Figure 4 is a fragmentary sectional illustration, taken in a plane normal to the duct axis and showing part of the duct as well as part of the throttling blades and a ring which supports them;; Figure 5 is a fragmentary longitudinal sectional elevation taken in a plane which contains the duct axis; Figure 5 showing part of the duct and part of the blades of Figure 4 as well as part of a structure for controlling the inclination of the blades; Figure 6 shows in elevation another embodiment of a throttling blade; Figure 7 is a fragmentary view of another structure for controlling the flow of gas in a plane normal to the duot axis, showing part of a duct and some of the blades of Figure 6 as well as a ring assembled with these blades; and Figure 8 is a fragmentary longitudinal sectional elevation, in a plane containing the duct axis, showing part of the duct and part of the blades and the ring of Figures 6 and 7 together with means for adjusting the blades.

The gas flow control structure 10 illustrated in Figures 1 to 3 includes a plurality of throttling blades 11, one of which is illustrated in Figure 3. These blades mutually overlap each other in the manner apparent from Figure 1. Thus, as is apparent from Figure 1, where only a relatively small number of blades are illustrated, the several throttling blades 11 engage each other with the surface of each blade which is apparent in Figure 1 extending behind and engaging the opposed surface of the next blade considered in a clockwise direction, as viewed in Figure 1.

The throttling blades 11 are pivotally supported by a ring 13 which surrounds a central axis passing through the centre of the ring and being normal to a plane containing the same, this axis coinciding with the axis of a duct 14 which is schematically illustrated in Figure 2. In order to pivotally support the blades 11 on the ring 13, these blades 11 may simply be hingedly connected to the ring. Thus each blade has a portion 12 formed with a bore passing therethrough, and the ring 13 passes through this bore so that in this way the blades 11 are 4wing- ably carried by the ring 13 to assume the different positions schematically illustrated in Figure 2. Thus, the blades 11 will form the side surface of a truncated cone.

The bored portions 12 of the blades 11 are distributed around the ring 13, Rhich may take the form of a simple wire passing through the bored portions 12. For example the ring 13 may take the form of a circular ring made of a steel wire which not only passes through the ibored portions 12 of the blade 11 but which also has a diameter substantially equal to 'the inner diameter of the duct 14 to which the ring 13 is fixed in any suitable way. If desired, for example, the duct 14 may be provided with an inner circular groove for receiving the steel wire and within this groove it is possible to provide circumferentially distributed apertures for the hinges :12 of the blades 11.

As may be seen from Figure 2, by way of any suitable means (not illustrated in Figure 2) such as a Thikage mechanism, it is possible to control the aperture through which the gas flows by turning the blades 11 about the ring 13, so as to control the taper of the truncated cone which is defined by the blades 11. As is apparent from Figure 2, the Iblades 11 have .upstream ends connected to the ring 13 and defining the base of the truncated cone while having downstream ends which define the throttling aperture through which the fluid must flow from the left toward the right, as viewed in Figure 2, along the interior of the duct 14.

When the blades 11 are adjusted to have the solid line position shown in Figure 2, the blades 11 will define at their downstream ends a throttling aperture as illustrated in Figure 1. The blades 11 can be turned so as to reduce the size of the throttling aperture, so that it is smaller than the aperture shown in Figure 1, and the blades 11 will now, for example, occupy the dot-dash line position shown in Figure 2 to the left of the solid line position. This latter position represents the maximum throttling apereure, i.e. a flow aperture of minimum size. On the other hand, the overlapping blades 11 can be turned so as to extend substantially along the inner surface throttling aperture, i.e. a flow aperture of of the duct 14, assuming now the dot-dotdash line position shown in Figure 2 to the right of the solid line position of the blades 11. This position represents the minimum flow aperture through which the gas can flow, and it will be noted that this maximum aperture corresponds approximately to the inner diameter of the duct 14. The shape and size of the throttling blades can be properly ohosen to fit a particular flow duct, and the flow aperture at maximum throttling can be made exceedingly small so that the air flow at this time can be practically zero.

Referring to Figures 4 and 5, there is fragmentarily illustrated therein the circular wire ring 13 extending through the apertured portions 12 at the upstream ends of the blades 11 so as to support the latter for pivotal movement. Axially bored spacers 16 are situated between the portions 12 to distribute the blades 11 properly along the wire ring 13. Some spacers 17 are fixed with bolts 18 passing respectively through openings 20 in the duct 14 and carrying nuts 19 for fixing the ring 13 in the manner shown in Figures 4 and 5. For example the spacers 17 with the fastening means connected thereto may be situated at 900 from each other along the ring 13.

By way of example there is shown in Figure 5 a tmeans for adjusting the blades 11, this means including one or more curved rods 21 extending along a circle whose centre is in the centre of the cross section of the ring 13 as shown in Figure 5. A guide tube 22 which also extends along this circle is fixedly carried by the duct 14, with the rod 21 passing slidably therethrough so as to be guided thereby. Outside the duct 14 the rod 21 carries a handle 23. A pair of these rods 21 and the structure associated therewith may be situated at diametrically opposed sides of the duct 14, so that the operator by moving the handles 23 toward or away from each other can change the inclination of the blades 11 so as to control the aperture through which the gas flows in the manner described above.Of course, because of their mutually overlapping rela tionship, each blade 11 will transmit its inward or outward movement to the neigh boring blades.

It is also possible as shown in Figures 7 and 8 to provide a ring 33 corresponding to the ring 13 but having a diameter substantially smaller than the inner diameter of the duot 14. In this case the blades 11 are replaced by blades 31 as illustrated in Figure 6. Thus these blades are provided with inwardly extending side notches 40 between which is located a bored hinge portion 42 through which the circular ring 33 passes. Between the portions 42 are located axially bored spacers 36 through which the ring 33 also passes, and some of these spacers 37 are fixed with bolts 38 at the exterior of the duct 14 as shown in Figures 7 and 8. These fasteners .38, 39, together ,with the spacers 37 fixed to the inner ends of the bolts 38, may be situated at 90" from each other around the ring 33.The blades 31 also overlap each other in the manner shown in Figures 7 and 8.

In order to adjust the inclination of the blades, one or more of the blades 31 have fixed thereto, e.g. by welding, a bracket 51 to which a rod 52 is pivotally connected at its inner end, this rod 52 passing through a short cylindrical slot 53 formed in the duct 14 and carrying at its outer end a handle 54. Thus a pair of rods 52, with the structure associated therewith, may be situated at diametrically opposed parts of the duct 14. As is apparent from Figure 8, by moving the rods 52 inwardly or outwardly it is possible to adjust the inclination of the blades 31 and thus the size of the throttling aperture defined by the downstream ends of the blades 31.While any suitable releasable holding devices may be provided for releasably maintaining the rods 52 (or the rods 21) in adjusted positions, the frictional engagement between the blades 31 .for the blades 11) will in general be sufficient for this purpose.

It will be noted that with the embodiment of Figures 6 to 8, as contrasted with that of Figures 1 to 5, when the throttling is reduced from the maximum throttling, where the flow aperture at the centre of the duct is at a minimum, there will be an increase in the annular flow aperture situ noted between the ring 33 and the inner surface of the duct 14. Thus, when the central downstream aperture defined iby the blades 3il increases, there is also an increase in the path of flow along the inner surface of the duct.

As was indicated above, although it is not necessary, releasable holding devices may be provided for holding the rods 21 or 52 in their adjusted positions. For this purpose the handles 23 and 54 may be removed, and a pair of lock nuts may be threaded onto these rods, such lock nuts engaging the outer end of the guide 22 in the case of Figure 5 and engaging the outer surface of the duct 14 in the case of Figure 8.

With the above-described structures a number of advantages are achieved. Thus, it will be seen that the control means requires very little space outside the duct.

Moreover, during adjustment of the blades the direction of gas flow remains unchanged, the gas flow remaining symmetrical with respect to the duct. The range of control is extremely wide, being practically from 0 to 100 percent, and the flow aperture can easily be made substantially equal to the cross-sectional interior area of the duct itself.

The control structure has favourable acoustic properties, in that during operation it creates very little noise. The manufacturing and mounting costs are extremely low. In addition, thermal lagging of the control means, or insulation thereof to avoid fire hazards can easily be carried out.

WHAT WE CLAIM IS: 1. A structure for controlling the flow of a gas comprising duct means through which the gas is to flow, the duct means having a predetermined axis, circular ring means situated in the duct means between opposed ends thereof and coaxially surrounding the said axis and ;being situated in a plane normal to the said axis, and a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. the blades 11 so as to support the latter for pivotal movement. Axially bored spacers 16 are situated between the portions 12 to distribute the blades 11 properly along the wire ring 13. Some spacers 17 are fixed with bolts 18 passing respectively through openings 20 in the duct 14 and carrying nuts 19 for fixing the ring 13 in the manner shown in Figures 4 and 5. For example the spacers 17 with the fastening means connected thereto may be situated at 900 from each other along the ring 13. By way of example there is shown in Figure 5 a tmeans for adjusting the blades 11, this means including one or more curved rods 21 extending along a circle whose centre is in the centre of the cross section of the ring 13 as shown in Figure 5. A guide tube 22 which also extends along this circle is fixedly carried by the duct 14, with the rod 21 passing slidably therethrough so as to be guided thereby. Outside the duct 14 the rod 21 carries a handle 23. A pair of these rods 21 and the structure associated therewith may be situated at diametrically opposed sides of the duct 14, so that the operator by moving the handles 23 toward or away from each other can change the inclination of the blades 11 so as to control the aperture through which the gas flows in the manner described above.Of course, because of their mutually overlapping rela tionship, each blade 11 will transmit its inward or outward movement to the neigh boring blades. It is also possible as shown in Figures 7 and 8 to provide a ring 33 corresponding to the ring 13 but having a diameter substantially smaller than the inner diameter of the duot 14. In this case the blades 11 are replaced by blades 31 as illustrated in Figure 6. Thus these blades are provided with inwardly extending side notches 40 between which is located a bored hinge portion 42 through which the circular ring 33 passes. Between the portions 42 are located axially bored spacers 36 through which the ring 33 also passes, and some of these spacers 37 are fixed with bolts 38 at the exterior of the duct 14 as shown in Figures 7 and 8. These fasteners .38, 39, together ,with the spacers 37 fixed to the inner ends of the bolts 38, may be situated at 90" from each other around the ring 33.The blades 31 also overlap each other in the manner shown in Figures 7 and 8. In order to adjust the inclination of the blades, one or more of the blades 31 have fixed thereto, e.g. by welding, a bracket 51 to which a rod 52 is pivotally connected at its inner end, this rod 52 passing through a short cylindrical slot 53 formed in the duct 14 and carrying at its outer end a handle 54. Thus a pair of rods 52, with the structure associated therewith, may be situated at diametrically opposed parts of the duct 14. As is apparent from Figure 8, by moving the rods 52 inwardly or outwardly it is possible to adjust the inclination of the blades 31 and thus the size of the throttling aperture defined by the downstream ends of the blades 31.While any suitable releasable holding devices may be provided for releasably maintaining the rods 52 (or the rods 21) in adjusted positions, the frictional engagement between the blades 31 .for the blades 11) will in general be sufficient for this purpose. It will be noted that with the embodiment of Figures 6 to 8, as contrasted with that of Figures 1 to 5, when the throttling is reduced from the maximum throttling, where the flow aperture at the centre of the duct is at a minimum, there will be an increase in the annular flow aperture situ noted between the ring 33 and the inner surface of the duct 14. Thus, when the central downstream aperture defined iby the blades 3il increases, there is also an increase in the path of flow along the inner surface of the duct. As was indicated above, although it is not necessary, releasable holding devices may be provided for holding the rods 21 or 52 in their adjusted positions. For this purpose the handles 23 and 54 may be removed, and a pair of lock nuts may be threaded onto these rods, such lock nuts engaging the outer end of the guide 22 in the case of Figure 5 and engaging the outer surface of the duct 14 in the case of Figure 8. With the above-described structures a number of advantages are achieved. Thus, it will be seen that the control means requires very little space outside the duct. Moreover, during adjustment of the blades the direction of gas flow remains unchanged, the gas flow remaining symmetrical with respect to the duct. The range of control is extremely wide, being practically from 0 to 100 percent, and the flow aperture can easily be made substantially equal to the cross-sectional interior area of the duct itself. The control structure has favourable acoustic properties, in that during operation it creates very little noise. The manufacturing and mounting costs are extremely low. In addition, thermal lagging of the control means, or insulation thereof to avoid fire hazards can easily be carried out. WHAT WE CLAIM IS:

1. A structure for controlling the flow of a gas comprising duct means through which the gas is to flow, the duct means having a predetermined axis, circular ring means situated in the duct means between opposed ends thereof and coaxially surrounding the said axis and ;being situated in a plane normal to the said axis, and a

plurality of throttling blades overlapping each other and distributed around the said axis and along the ring means, the blades defining the side surface of a truncated cone whose axis coincides with the said predetermined axis, the blades having upstream ends defining the base of the truncated cone and downstream ends defining the apex . ' the truncated cone, and the ring means supporting said blades for ,pivotal movement around the ring means for adjusting the inclination of the blades relative to the said axis and thus the size of the apex to control the size of an aperture defined by the downstream ends of the blades through which aperture the gas in the duct means flows, so that the flow of air through the duct canbe regulated by situating the 'blades at a selected inclination, the side edge portions of the blades overlapping to such an extent that they remain overlapping along their entire length during adjustment of the inclination.

2. A structure as claimed in claim 1, wherein the ring means is of a diameter substantially equal to the inner diameter of the duct means, and the blades are pivotally connected to the ring means at the upstream ends of the blades.

3. A structure as claimed in claim 1, wherein the ring means has a diameter smaller than the diameter of the duct means and the blades are pivotally connected with the ring means between the upstream and downstream ends of the blades

4. A structure as claimed in any of claims 1 to 3, including adjusting means operatively connected with at least one blade but not to blades which respectively adjoin and overlap the said one blade, for adjusting the inclination of the said one blade while transmitting the adjustment movement of the said one blade to the adjoining blades, the adjusting means maintaining the blades in their adjusted position when the gas flows through the duct means as well as when the gas does not flow through the duct means.

5. A structure as claimed in claim 4, wherein the adjusting means extends through a wall portion of the duct means and has at the exterior of the duct means a portion which is accessible for carrying out the adjustment.

6. A structure for controlling the flow of gas, substantially as described herein with reference to, and as shown in, Figures 1 to 5 or Figures 6 to 8 of the accompanying drawings. ~ ~ ~ ~~