WO1998030085A1

WO1998030085A1 - Cattle shed ventilation system with air intake valves, and such valves for such systems

Info

Publication number: WO1998030085A1
Application number: PCT/DK1998/000013
Authority: WO
Inventors: John L. Christensen
Original assignee: Skov AS
Current assignee: Skov AS
Priority date: 1997-01-09
Filing date: 1998-01-09
Publication date: 1998-07-16
Anticipated expiration: 1999-07-09
Also published as: AU5312798A

Abstract

With the use of wall-mounted air intake valves in cattle shed ventilation systems, it is known to employ valves (2) with angularly-disposed dampers (4) which, by means of a draw-string (8), can be controlled for graduated opening and closing by a pivoting movement around a lower edge, and it is also known to be advantageous to be able to regulate the coupling relationship between the draw-string and these pivotable dampers. The invention makes this possible in a particularly simple manner, in that the individual pivotable dampers are provided with string-fastening means (10) which are disposed either in at least two different height positions on the damper or are adjustable between such positions, e.g. merely by the turning of an adjusting knob (18).

Description

Cattle shed ventilation system with air intake valves, and such valves for such systems.

The present invention concerns a cattle shed ventilation system with air intake valves, and also such valves for such systems. It is widespread practice that use is hereby made of wall-mounted intake valves configured in a box-like manner as rectangular ducts with a pivotable damper which from an outer lower-edge area ex- tends at an angle upwards and inwards for closing against an upper seating-edge area at the inner end of the box or the rectangular duct. The damper is spring-loaded to swing upwards towards this closed position, and thus in a simple manner can be disposed for controlled opening merely by being connected with a draw-string, by means of which it can be drawn down to provide a smaller or larger opening .

With the system under consideration, there will normally be involved a whole series of such intake valves which are controlled from a common regulation station, i.e. by means of a horizontal and longitudinally-movable drawbar extending from said valves, said bar being connected at the individual intake vales to the above- mentioned draw-string, which from an extent lengthwise with the bar thereafter extends upwardly for connection with the damper via a reversing roller at the lower edge of the inside end of the box or the rectangular duct. A displacement of the drawbar in one direction will hereby result in a controllable opening of the dampers, which can also be closed in a controllable manner by displacement of the bar in the opposite direction.

Normally, the air intake is established by creating a certain underpressure in the cattle shed by means of roof -mounted extraction fans which can work with requirement-controlled effect, and whereby it is relevant to regulate the intake valves in order to achieve the desired admission characteristic of the sucked-in air. It is herewith of importance that the system works with angularly-disposed, pivotable dampers, in that with a slight degree of opening these will have an upwardly-controlling influence on the intake air, which is advantageous for a good distribution of air in the cattle shed when operating with a low air exchange in connection with cold external air.

For an optimised function of the relevant ventilation systems, advanced, computer-based control systems have already been established which can determine the exchange of air depending on the temperature conditions. However, conditions can arise in the individual installations which make it desirable to effect a mechanical regulation of the reaction of the dampers to arising setting influences. Examples of this can be seen in DK-C- 150,399 and EP-0678185, both of which deal with differen- tiated exchange conditions between the horizontal displacement of the above-mentioned drawbar and the strings which connects this with the individual dampers. Regard can hereby be paid to conditions other than those which can be accommodated by the computer control, the extent of which does not, after all, replace the very simple mechanical, common control of the individual dampers via the said drawbar. Extra regulation possibilities can be achieved by altering the transfer characteristic between the displacement of the drawbar and the associated verti- cal swinging movement of the individual dampers, or merely just one of said dampers.

With the said known arrangements, this is achieved by using special systems for changing the effective length of the string between the drawbar and the dampers by means of pulleys, but with the present invention it has been found that use can be made of another and quite simple and effective possibility of changeover, i.e. a moving of the string's point of action on the damper. From the construction point of view, this can be arranged in an extremely simple manner, i.e. by configuring the dampers with two or more string holders at different effective distances from the pivotal axes of the dampers or - preferably - by providing them with a single string holder which by means of an adjusting knob is changeable between two or more such positions, without the string having to be removed from the holder. All depending on the desired opening characteristic, it will in any case in principle be possible to remount the string with a corresponding length adjustment which, however, can also be effected by moving the string's fixing bracket on the drawbar for holding the string tight when the damper is in the open position, such as is known in itself from DE-A-1 753 262. It will be understood that with a given displacement of the drawbar, the damper will move through a greater or smaller angle, all depending on whether the fixing of the string to the damper lies at a respectively smaller or greater distance from the turning axis of the damper, and with the disclosed simple possibilities of adjustment it will thus be easy to effect individual readjustments of the function characteristic of the commonly-controlled dampers in achieving desirable differentiations . In principle, use can hereby be made of steplessly-variable settings, but with the invention it has been found that it will be predominantly sufficient to be able to choose between merely two different settings, which naturally involves a simplification of the setting means. It has hereby been found possible to work with such a positioning and distance between the points of action which correspond to the difference between the string movements required to bring the damper to the fully open position by use of the respective points of action. If the one point of action corresponds to an ordinary course of regulation between fully closed and fully open position, it can thus be achieved with the use of the second point of action that the opening is de- layed, because the string is now slack with a certain over-length, so that the opening is not initiated until the string is tightened, but still completed simultaneously with the opening of the "ordinary" valves. A desired differentiation can hereby be achieved merely by a changeover between the points of action, and furthermore without any need to change the fastening of the string on the drawbar.

It must be mentioned that it is known to operate the dampers in a "reverse" manner, i.e. by these being opened under their own spring power and closed by drawing the string upwards, so that the opening is controlled by a slackening of the string. Here, a corresponding changeover can be used when drawsprings are inserted in the strings to the valves which are to work with delayed opening.

The invention will now be described in more detail with reference to the drawing, in that fig. 1 is a perspective view of the inside of an intake valve according to the invention, fig. 2 is a more detailed view of a string fastening part thereof, and fig. 3 shows a side section thereof. In fig. 1 is shown the inside end of a wall- mounted air intake valve consisting of a rectangular duct 2 in which is disposed a damper 4 which, from an upwardly-sloping closed position, is pivotable downwards around a lower hinge connection 6 by the pulling down a string 8, said string being connected to a fastening ele- ment 10 on the damper 4 and via a fixed reversing roller 12 to an horizontally-extending drawbar 14 which extends from a not-shown drive station. This can have, for example, computer-controlled means for the displacement of the drawbar 14 and herewith generally for the opening and closing movements of the damper 4 depending on variations which arise in the detected ventilation requirements.

However, according to the invention it will be possible to further differentiate this control, i.e. by moving the point of action 10 for the string 8 on the damper 4 on selected valves 2, e.g., by providing the dampers with two or more hooks or eyes in different positions .

Alternatively, with a preferred embodiment use is made of a movable string holder in the form of a re- taining ring 10 which is provided on an arm part 16 extending radially from a rotatable disk 18 which has an element 20 for manual control, fig. 2. As also shown in fig. 3, the disk 18 has an associated rear-disk 22 by means of which the disk 18 can be rotatably mounted in a round hole 24 in the damper 4, so that the disk is rotatable with a suitable degree of friction. The object is to enable the eye 10 to be brought into the two positions, as shown in fig. 3, i.e. with the arm 16 extending upwards or downwards, and if necessary a snap-lock or ex- tra fastening means can be established for selectively retaining the eye 10 in these positions, for example by providing the back of the arm 16 with a projection which can enter into snap-lock connection with relevant recesses in the front of the damper 4. From fig. 3 it will be seen that with a given longitudinal displacement of the drawbar 14 for the drawing down of the string 8 with the shown force L, a differentiated drawing-down of the damper 4 will take place depending on whether the eye 10 is placed in its upper or lower position, in that the closer the eye 10 lies to the damper's pivot axis 6, the greater or quicker the swinging-down. As mentioned, the relationships can be adjusted so that by using the eye 10 in the lower position, the string 8 will be slackened so much that a relevant delaying of the initial opening occurs, while a drawing-down to fully open position will be achieved at the same time with the dampers in those valves where the eye 10 is used in its upper position, i.e. without differentiation. Fig. 4 shows a preferred modification of the system for turning, cf. figs. 2 and 3. Here, the adjusting knob 20 is provided on the inner side of the damper 4 inside the housing 2, while on the outside there are provided eye elements 10 which are individually retained in a rotatable manner by means of an eccentrically-disposed bolt 24, which also holds the two parts 18 and 22 together. When a turning of the system is carried out, it is possible simultaneously to effect a counter-turning of the eye element 10, whereby the string 8 is not twisted.

Claims

C A I M S

1. Cattle shed ventilation system with wall- mounted air intake valves in the form of a duct which internally cooperates with a pivotable damper, which from a hinged lower-edge area inside the duct extends at an angle upwards and inwards for closing against an upper seating-edge area at the inside end of the duct, said damper being permanently stressed either towards swinging up into the closed position or to swinging down from this, and at an upper area being connected to a drawstring which forms part of a control system for greater or lesser degrees of opening of the dampers by drawing these down or up respectively, c h a r a c t e r i z e d in that the dampers are configured with means which en- able a coupling of the draw-string to points of action in at least two different height positions on the damper.

2. Air intake valve for a system according to claim 1, c h a r a c t e r i z e d in that the damper is configured with means which enable a coupling of the draw-spring to points of action in at least two different height positions on the damper.

3. Air intake valve according to claim 2, c h a r a c t e r i z e d in that the dampers have at least two fastening elements for the draw-string.

4. Air intake valve according to claim 2, c h a r a c t e r i z e d in that the dampers have a single string-fastening element which is connected to the damper in a height-adjustable manner.

5. Air intake valve according to claim 4, c h a r a c t e r i z e d in that the fastening element is eccentrically-disposed on an under support which is rotatable in relation to the damper.

6. Air intake valve according to claim 5, c h a r a c t e r i z e d in that said under support is a ro- tatable disk which supports the fastening element on the one side of the damper, and which is connected to a turning element accessible from the other side of the damper.