WO1996023178A1

WO1996023178A1 - Arrangement in a valve comprising a first displaceable valve element and a second stationary element

Info

Publication number: WO1996023178A1
Application number: PCT/NO1996/000002
Authority: WO
Inventors: Arne Torsvik
Original assignee: Norin A/S Laboratorie- Og Sykehusinnredning
Priority date: 1995-01-20
Filing date: 1996-01-09
Publication date: 1996-08-01
Also published as: AU4591196A

Abstract

The present invention relates to an arrangement in a valve (230), especially in a regulation valve for ventilation, which valve (230) is mounted in a valve housing (201) and comprises one or more valve elements which can be moved between positions which close and open said valve, said valve elements comprising a first displaceable valve element (230a) which is adapted to rotate about a centrally mounted shaft (232) in said valve housing (201), as well as a second stationary valve element (230b) having substantially the same shape and area as said first displaceable valve element (230a), and for the purpose of providing a valve which exhibits minimum hysteresis, which renders accurate and rapid regulation of the throughput volume of fluid, and which also renders a so say noisefree passage of air, it is according to the invention suggested that a stationary valve element (230b) is affixed in the inner wall of the valve housing (201) and at its central inner portion carries the rotating shaft (232) for the displaceable valve elements (230a), as well as a transmission element rotatably arranged on said shaft (230), for example a driving toothed wheel (282), for driving a displaceable valve element (230a).

Description

Arrangement in a valve comprising a first displaceable valve element and a second stationary element.

Field of the invention

The present invention relates to an arrangement in a valve, especially in a regulation valve for ventilation, which valve is mounted in a valve housing and comprises one or more valve elements which can be moved between positions which close and open said valve, said valve elements comprising a first displaceable valve element which is adapted to rotate about a centrally mounted shaft in said valve housing, as well as a second station¬ ary valve element having substantially the same shape and area as said first displaceable valve element.

Allthough the present valve has specifically been deve¬ loped in connection with ventilation in vent cabinets, it is to be understood that the valve may generally be app¬ licable also as fire valve and regulation valve in air condition installations in buildings.

Prior Art

From NO 166 462 (Halton Oy) there is know a method and a device for controlling volumetrically the flow velocity in air conditioning installations, there being used un- linearized control signal functions, and there being suggested a control valve in the form of a plate which can be turned about a shaft which is arranged transverse- ly to the channel in which the plate is located.

From NO 159 121 (Gebriiber Trox GmbH) there is known a device for pressure measurement in an air channel in a climatic technical construction, in which there is used a valve which can turn about an axis which is arranged in the middle of the valve, so that on each side of the turning axis there will be equally large parts of the valve. The prior art valve is mounted in a cylindrically shaped container, in which container there is also mount¬ ed star-shaped arms which are used for pressure measure¬ ments.

From NO 107 321 (Grove) there is known a valve structure for regulating the flow of fluids, in which a valve slide can be moved between open and closed position in relation to right opposite each other arranged throughflowing channels in a valve housing.

From NO B 154 841 there is know a turning sector valve having two valve plates with equal punched sector open¬ ings arranged turnable in relation to each other. It is true that according to NO 156 841 there is suggested a central drive shaft around which the turnable valve plate can rotate, but the regulating means itself takes the form of a rod which is turnably supported some distance down the turnable valve plate.

From US 1 192 689 there is for example known a valve having circumferential control, which is also the case with the technique according to US 1 986 252. US 3 110 323 relates to a seat valve provided with biassing springs, whereas US 3 396 904 relates to a fan valve wherein is used a lever as a regulating means.

US 4 328 831 relates to a turnable valve being controlled pneumatically through some sort of arm-shaped vane, and US 4 554 943 also relates to control of rotating valve by means of circumferentially arranged driving means.

Objects of the invention

One object of the present invention is to provide an arrangement in a valve which renders a so to say noise free passage of air when the valve allows air throughput through the valve housing.

Another object of the invention is to provide a valve which can be regulated in a simple and accurate way, as well as has a reaction time which meets heavy require¬ ments specifically in connection with vent cabinets.

A further object of the invention is to provide a valve which so to say has no hysteresis, for thereby providing a more accurate regulation.

Yet an object of the invention is to provide a valve which reduces the risk of oscillations when using a plu¬ rality of vent cabinets in the same room.

Summary of the invention

These objects are achieved in an arrangement as stated in the preamble, which according the invention is character- ized in that a stationary valve element is affixed in the inner wall of the valve housing and at its central inner portion carries the rotating shaft for the displaceable valve elements, as well as a transmission element rotat- ably arranged on said shaft, for example a driving toothed wheel, for driving a displaceable valve element.

More specifically, the invention is to the fact that at the central area of said valve element there is mounted a gear exchange which is driven by a motor, for example a step motor controlled by a control means.

A favourable embodiment involves that the gear exchange which is located in the central area of said valve ele¬ ments, is driven by a substantially diametrically arrang- ed shaft which is arranged behind an opposite pair of stationary valve element portions. In order to achieve minimum noise during operation, it is specifically important that the valve edges are rounded with an appropriate bending radius, for example a bending radius corresponding to the thickness of the valve ele- ment.

By locating the gear exchange in concealment of the cen¬ tral area of said valve elements there are achieved a plurality of advantages. Firstly, the driving force can be transmitted directly to the central portion of the rotatable valve, which will involve a symmetrical dis¬ tribution of forces, at the same time as one will avoid any play which may occur in other types of operation, for example radial displacement or lever displacement of the valve elements.

Further, there is achieved the advantage that also the driving shaft will be "concealed" behind the stationary valve elements, which further contributes to avoiding any structural parts protruding into the air throughput open¬ ings, whether these are almost closed, semi-open or fully open.

By using a gear exchange arranged in the central area of the valve elements, by using a substantially diametrical¬ ly arranged shaft behind an opposite pair of stationary valve elements, as well as by using helical toothed wheels in the gear exchange, there is according to the present invention achieved a valve regulation in which the hysteresis is reduced to a minimum.

A control means for controlling such an arrangement can appropriately receive signals about opening or closing of the valve in dependence of previous position of the valve and conditions for controlling the same.

Such control signals can for example be signals from a transmitter, for example a potentiometer which transmits a signal representing the degree of opening of a front hatch in a vent cabinet wherein the arrangement according to the invention can be mounted. Further, the control means may receive signals from a differential pressure transmitter which constantly measures the pressure dif¬ ference in question across said valve.

With such an arrangement in a valve and with such a con- trol of said valve, especially in connection with vent cabinets, there may be achieved a very rapid, effective and accurate regulation of air volume in a vent cabinet, for example from 100-700 m³/h.

Further features and advantages in connection with the present invention will appear from the following descrip¬ tion taken in connection with the appending drawings, as well as from the appending patent claims.

Brief disclosure of the drawings

Fig. 1 illustrates perspectively a segment of a vent cabinet, wherein an arrangement in a valve according to the invention can be applied.

Fig. 2 is a schematical block regulation diagram which can be used in the regulation of a valve according to the invention.

Fig. 3 is a plan view, on a larger scale, of a displaceable valve element which is included in an em¬ bodiment of the arrangement according to the invention.

Fig. 4 is a top view of the valve element illustrated in Fig. 3.

Figures 5 and 6 illustrate two perspective pictures seen from below and obliquely from the side, respectively, of a valve housing with associated control apparatus, where¬ in an arrangement according to the invention is mounted.

Figures 7 and 8 illustrate pictures of the inner of the valve housing, wherein is mounted a appropriate embodi¬ ment of the arrangement according to the invention, said Figures illustrating the valve in a partly opened posi¬ tion, which allows a certain throughput area for fluids or air.

Figures 9 and 10 correspond to the pictures of Figures 7 and 8, respectively, and illustrate here the valve in fully open position.

Fig. 11 illustrates a picture similarly to Fig. 7, but on a larger scale, specifically in the area of an example of a gear exchange.

Detailed description of embodiments

In Fig. 1 there is illustrated a perspective segment of a vent cabinet 1 in which the arrangement according to the invention can be mounted. Such a vent cabinet 1 may com- prise a working chamber 2 which can be closed by a front hatch 8 as well as means 13 for extraction of air through the working opening 8a and out from the working chamber 2.

The lower portion 8r of the front hatch 8, adjoining side portions 8s, 8t of the input opening 8a and the front portion 8u of the bottom 7 of the working chamber 2 can appropriately be rounded inwardly, for example following a section of an eliptic curve, for thereby achieving favourable flow conditions. Further, in the working cham¬ ber 2 there may be provided a rear double wall 3 which at its lower portion 3a defines a slit 4 for a first lami- nated exhaust along the bottom 7 and out through the rear slit 4, especially for heavier air particles, the rear double wall 3 extending upwardly along the rear wall 2 of the cabinet and defining a lower part of a plenum chamber 5. At its upper portion 3b the double wall 3 may merge into a downwardly open container or trough defining the top 10 of the working chamber 2.

At the top 10 of the cabinet 1 and above the plenum cham- ber 5 there may be arranged an extraction fan 15 and a controllable valve, schematically designated by a refer¬ ence numeral 16, the regulation of the fan 15 and the valve 16 being dependable upon the inlet opening 8a defined by the position of the front hatch 8.

At the hatch 8 there may thus, in an appropriate manner, be arranged a first sensor means 17, for example a potentiometer, which measures the position of the front hatch 8 in relation to the working opening 8a, and this potentiometer can thus deliver a signal A representing the degree of opening of the working hatch 8 of the vent cabinet, which signal appropriately may be supplied to a regulator 19, see Fig. 2.

In Fig. 2 it is depicted that the regulator 19, aside from being supplied with the signal A from the transmit¬ ter 17, also will be supplied with a signal representing the pressure drop Δp which is measured by means of a pressure drop sensor 18, and the means 17 and 18 cooper- ate with the regulator 19 in such a manner that the valve 16 and/or the fan 15 which appropriately can be mounted in an upper discharge connecting pipe 13, regulates the air velocity in the plane of the hatch 8 to suitable values, depending on the conditions prevailing during operation of the vent cabinet 1.

In Figures 3 and 4 there is illustrated schematically, on a larger scale, a specific embodiment of a displaceable valve element 130a according to the invention, said valve element 130a here being provided with two opposite circle sectors, each having 90° area coverage, 130aw and 130ax, respectively. It is in Fig. 4 illustrated that the thick¬ ness of the valve element 130a itself can be a thickness t, for example of 12 mm, and that the rounding radius R along the edges 130aa of the valve element 130a can have the same dimension as said thickness t, namely for example 12 mm.

In Figures 5 and 6 there is illustrated a valve housing 201 wherein there is mounted an embodiment of an arrange¬ ment in a valve, especially a regulating valve 230, as this appears from Figures 7-11, including a first displaceable valve element 230a provided for example similarly to what has been illustrated in Figures 3 and 4, as well as a corresponding stationary valve element 230b, wherein each of the elements here are provided with two circle sectors having approx. 90° area, and the Fig¬ ures 7 and 8 illustrating the valve with somewhat larger throughput areas 240a, 240b, and Figures 9 and 10 illus¬ trating the valve 230 in fully open position with throughput openings 240a, 240b corresponding to 180° throughput opening through the cylinder-shaped housing 201.

In Fig. 6 there is also illustrated cannula pipes 141a and 141b for measuring data to an appropriate control device.

In Figures 7 and 8 it is illustrated that the stationary valve element 230b is affixed to the inner wall of the valve housing 201 and at its central inner portion carries a rotating shaft 232 which in turn carries a transmission element, for example a toothed wheel 282, which is included in a gear exchange 250 which in turn is driven by a diametrically arranged shaft 251.

Especially in Fig. 7 it is illustrated that said gear exchange 250 which via said shaft 251 is driven by for example a step motor arranged in a control housing 260, which control housing 260, see specifically Fig. 5, is provided with a wheel 270 which indicates appropriate parametres, for example the position of the rotating shaft and thereby the position of the rotating valve element and consequently the degree of opening of said valve.

Further, Fig. 11 illustrates the gear exchange 250 with the here throughgoing shaft 251 , which appropriately is supported at each end, as well as provided with two cen¬ tral bearings 250a and 250b, between which the shaft 251 carries a first helical toothed wheel 280 and a second helical toothed wheel 281, especially helical, conical toothed wheels. The two shaft driven helical toothed wheels 280 and 281 engage a third helical toothed wheel 282 arranged on the rotating valve element 230a.

Appropriately, the three toothed wheels 280, 281 and 282 may be so adapted in relation to each other that 30% overlap is provided in the next drive gear before the preceding slips. In this manner there is achieved a very high precision and very small hysteresis, which appears from test results, indicating maximum 3% deviation.

It is to be understood that on the shaft there may be provided only one toothed wheel, especially a helical toothed wheel which engages one corresponding toothed wheel on the rotatable valve element.

In Figures 5-9 there is also illustrated a sensor means

261 , or a differential pressure transmitter which through a hose outlet 161a and 161b, see Fig. 9, communicates with the previously discussed cannula pipes 141a 141b measuring continuously the pressure difference in ques¬ tion across the valve. A signal corresponding to this pressure difference Δp is transmitted to for example a not illustrated programmable logic control (PLS) which receives signals about opening or closing the valve de¬ pending on the previous position of the valve and the conditions for controlling the same.

The logic control or the regulator is adapted to receive signals from the previously mentioned transmitter, for example a potentiometer transmitting a signal represent¬ ing the opening degree of the working hatch in a vent cabinet, see otherwise Figures 1 and 2.

Used in connection with an installation for regulating the volume of air in a vent cabinet, one can in connec¬ tion with the present valve achieved very good regula¬ tions from for example 100-700 m³/h.

Tests have revealed that by registering the connection between volume of air, hight of hatch, air velocity in hatch, as well as total of air (air supply and extrac¬ tion) for a situation in which the working hatch in an air cabinet is opened to a hatch hight of approx. 0,55 m, one will after approximately only three seconds achieve a substantial air velocity via said hatch, which will oscillate to a value of approx. 0,3 m/s.

It has been revealed by measuring corresponding values in connection with closing of a working hatch in a vent cabinet, that both air volume and air velocity of the hatch indicate a favourable dampening oscillating course.

A hysteresis test for a valve according to the invention indicates that according to the test results involving a valve having diameter 250 mm and 240 volts alternating current motor and pressure drop 100 Pa across the valve, will result in very small hysteresis.

It is to be understood that a valve according to the described type can also be used as a measuring diaphragm, the rotating shaft, respectively the motor/driving shaft being set in a specific position indicating the degree of opening of the valve, see the adjusting wheel 270 in Fig. 5, and from the differential pressure 261 one can then extract a value corresponding to air or fluid throughput for various valve openings.

Besides, test results indicate that an approximately linear valve is achieved by the embodiment illustrated in Figures 5-11, i.e. an air throughput which is very close¬ ly proportional to the opening degree and exhibits mini¬ mum hysteresis.

The use of two 90° wings for displaceable and stationary valve elements, respectively, renders a symmetrical structure of the valve, there is achieved an equally distributed throughput picture in the valve housing, there is achieved stable mounting in the valve housing, and there is achieved a central and accurate power centre in the middle of the valve.

However, it is to be understood that according to the invention the first and second valve elements may com¬ prise one or more substantially similar elements, prefer- ably circle sectors which in closed position are arranged side by side, but which in opened position are mutually overlapping, but with intermediate openings for air throughput.

Of course, said first and second valve elements can also comprise not only four circle sectors as this is illus¬ trated in the embodiment depicted in Figures 5-11, but can also comprise for example one circle sector having approx. 180° area. Differently from two opposite circle sectors, each of which having approx. 90° area, which is illustrated in Figures 5 and 6, a valve may possibly be provided with three circle sectors which are evenly dis¬ tributed around the centre axis, each having approx. 60° area coverage, or possibly comprise eight circle sectors having approx. 22,50° area coverage, etc.

It is to be understood that the number of circle sectors or "rings" with which the valve elements can be provided, will be dependent upon the field of application, it being possible for the air throughput in opposite quadrants to choose between 22,5°-45° and 90° opening, by having eight-four, respectively two, openings for air through¬ put. The valve may appropriately be manoeuvred through step motor or gear motor which can be connected in a simple manner.

Claims

P a t e n t c l a i m s

1. Arrangement in a valve (230), especially in a regu¬ lation valve for ventilation, which valve (230) is mounted in a valve housing (201) and comprises one or more valve elements which can be moved between positions which close and open said valve, said valve elements comprising a first displaceable valve element (230a) which is adapted to rotate about a centrally mounted shaft (232) in said valve housing (201), as well as a second stationary valve element (230b) having substan¬ tially the same shape and area as said first displaceable valve element (230a), c h a r a c t e r i z e d i n that a stationary valve element (230b) is affixed in the inner wall of the valve housing (201) and at its central inner portion carries the rotating shaft (232) for the displaceable valve elements (230a), as well as a transmission element rotat- ably arranged on said shaft (230), for example a driving toothed wheel (282), for driving a displaceable valve element (230a).

2. Arrangement as claimed in claim 1, c h a r a c t e r i z e d i n that at the central area of said valve elements (230a, 230b) there is mounted a gear exchange (250) which is driven by a motor (260), for example a step motor controlled by a control means (19).

3. Arrangement as claimed in claim 1 or 2, c h a r a c t e r i z e d i n that the gear exchange (250) which is located in the central area of said valve elements (230a, 230b) is driven by a substantially dia¬ metrically arranged shaft (251) provided behind a corres¬ ponding pair of stationary valve element portions (230b).

4. Arrangement as claimed in any of the preceding claims. c h a r a c t e r i z e d i n that the gear exchange (250) is mounted at the central portion of both the displaceable (230a) and the stationary valve element (230b), and that the gear exchange (250) is driven by a throughgoing shaft (251) which at its central portion carries at least one toothed wheel, specifically a helical toothed wheel, which engages at least one toothed wheel on the displaceable valve element.

5. Arrangement as claimed in claims 1-3, c h a r a c t e r i z e d i n that gear exchange (250) is mounted at the central portion of both the displaceable (230a) and the stationary valve element (230b), and that the gear exchange (250) is driven by a throughgoing shaft (251), which at its central portion carries a first (280) and a second (281) helical toothed wheel driven by the throughgoing shaft (251), and both of which engaging an intermediate third helical toothed wheel (282) mounted on the displaceable valve element (230a).

6. Arrangement as claimed in claim 4 or 5, c h a r a c t e r i z e d i n that the helical toothed wheels (280, 281, 282) are mutually adapted with approx. 30% overlap from drive gear to drive gear.

7. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that both the stationary element and the displaceable element comprise valve edges which are rounded with a rounding radius (R) which is equal to the thickness (t) of the valve element itself.

8. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that said first and second valve elements comprise one or more substantially similar element pieces, preferably circle sectors which in closed position are arranged side by side, and which in open position are mutually overlapping, having inter¬ mediate throughput openings for air.

9. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that said first and second valve elements each comprise a circle sector hav- ing approx. 180° area, possibly comprising two opposite circle sectors (130aw, 130ax) having approx. 90° area, possibly three circle sectors with approx. 60° area even¬ ly distributed around the central axis, possibly compris¬ ing four circle sectors (30aw-30az, 30bw-30bz) having approx. 45° area, or more, or possibly comprising eight circle sectors having approx. 22,5° area coverage, etc.

10. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that the rotating displaceable valve element (230a) receives signals about opening or closing said valve (230) in dependence of the previous position (270) of said valve and conditions for controlling the same.

11. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that the valve (16) is included in an installation for regulating the volume of air in a vent cabinet (1), for example 100-700 m³/h.

12. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that the displaceable valve element (230a) is controlled via said control means (19) by receiving a signal (A) from a transmitter, for example a potentiometer (17) which transmits a signal representing the degree of opening of the working hatch (8) in a vent cabinet (1).

13. Arrangement as claimed in any of the preceding claims, c h a r a c t e r i z e d i n that the valve element (230a) is controlled by the control means (261) receiving signal from a differential pressure transmitter (18, Δp) measuring at any time the pressure difference in question across said valve (230).