[0001] The present invention relates to a valve for controlling the ventilation flow from
a kitchen range hood, comprising means which permit a basic flow of ventilation air
to pass through the valve in its closed position.
[0002] Such a valve is known by our Swedish patent No. 8206526-9, which comprises a through
opening, through which a basic flow of ventilation air passes in the closed position
of the valve. The size of this opening can be adjusted at the installation of the
valve in the exhaust air outlet of the range hood by cutting off a portion of a conically
tapered tube.
[0003] The present invention intends to improve such a valve by making it so that the size
of the basic flow of ventilation air can be adjusted more accurately and even be
readjusted later.
[0004] In order to achieve this, a valve of the type described by way of introduction is
characterized according to the invention in that the valve has an opening, the area
of which is adjustable. The area of the opening can thereby be set very accurately
depending on the measured values of the pressure drop over the valve in the closed
position. Furthermore, it is possible to readjust the area of the opening later if
this should prove necessary, for example due to altered flow conditions in the exhaust
duct.
[0005] A preferred embodiment of the invention will now be described with reference to
the accompanying drawings, in which:
Figure 1 shows in perspective a valve according to a pre ferred embodiment of the
invention,
Figure 2 shows a plan view of a valve cover included in the valve shown in Figure
1,
Figure 3 shows a plan view of a constriction disk in the valve according to Figure
1, and
Figures 4 and 5 show a plan view and an axial section throguh a pipe stub supporting
the valve cover and the constriction disk.
[0006] The valve shown in Figure 1 has three main components, namely a valve cover 1, a
constriction disk 2 and a pipe stub 3, which supports the valve cover 1 and the constriction
disk 2. The valve cover 1 is hinged 4 to an end flange 5 of the pipe stub 3. Furthermore,
the valve cover is dimensioned so that it covers in the closed position of the valve
the opening of the pipe stub 3 since the outer peripheral portion will be in contact
with an inner portion of the ring surface of the end flange 5. The constriction
disk 2 is also fixed in a suitable manner to the flanged end of the pipe stub 3.
[0007] The entire valve is fixed in a suitable manner in a range hood (not shown) with the
non-flanged end of the pipe stub 3 connected to the evacuation duct of a central ventilation
system. In the opened positioned of the valve shown in Figure 1, air is evacuated
from the interior of the range hood through the constriction disk 2 and the pipe stub
3 to the evacuation duct 3. The size of the flow through the constriction disk can
be adjusted by changing the size of the opening therein. For this purpose, as is best
shown in Figure 3, the constriction disk 2 is provided with, in addition to a minimum
opening 6, rupture indications 7 to facilitate the making of a larger opening in the
constriction disk.
[0008] As can be seen in Figures 1 and 2, the valve cover 1 also has an opening 8 which,
as can best be seen in Figure 1, is made in a portion of the valve cover projecting
towards the pipe stub. In the closed position of the valve, this projecting portion
of the valve cover 1 extends through the opening 6 of the constriction disk 2. Even
when the valve is closed, air will flow from the interior of the range hood through
the opening in the valve cover to the evacuation duct. In order to make it possible
to adjust the size of this basic flow of ventilation air, a sliding shutter 9 is slideably
mounted in the valve cover 1 with the aid of guides 10. The sliding shutter 9 makes
it possible to cover the opening 8 to the desired degree. A scale 1, as shown in Figure
2, can preferably be arranged beside the opening 8 to determine the position of the
sliding shutter 9 relative to the opening.
[0009] A metering outlet 12 is arranged in the pipe stub 3 to make it possible to measure
the pressure drop over the valve. The metering outlet 12 consists of a tube opened
at both ends, which extends from a position upstream of the flange 5 through the flange
peripherially outside the valve cover in its closed position and through the wall
of the pipe stub 3 opening into the interior of the pipe stub downstream of the constriction
disk 2. By integrating the metering outlet with the pipe stub and making it easily
accessible through its end projecting from the flenge 5, to which a measuring instrument
can easily be connected, the pressure drop over the valve can be measured with the
valve mounted in place without intervention on the pipe stub or the evacuation duct
regardless of whether the valve is opened or closed. The installation and adjustment
of a range hood with such a valve is thus facilitated significantly over previously
known designs. The size of the openings 6 and 8 in the open and closed positions of
the valve can thus be selected and adjusted depending on the measured pressure drop.
By making the valve cover with an opening with an adjustable cross sectional area,
a very accurate adjustment of the basic flow of ventilation air can De made. Furthermore,
the position of the sliding shutter 9 can be changed if changed flow conditions should
arise for any reason in the central ventilation system. In the example shown, the
sliding shutter 9 is easily accessible, when the valve is in its closed position,
for adjustment from the non-flanged end of the pipe stub 3, if the pipe stub is removed
from the evacuation duct. Preferably, however, the sliding shutter is also accessible
from the underside of the range hood when the range hood filter unit is removed. The
position of the sliding shutter can thereby be changed without completely or partially
removing the valve.
[0010] The valve cover 1 also comprises a bow 14, coupled to an actuating mechanism (not
shown) disposed in the range hood for swinging the valve cover between a closed and
an open position.
[0011] The valve according to the invention thus provides a simple and exact method of adjusting
and/or readjusting the basic flow of ventilation air in a range hood.
[0012] A number of modifications of the embodiment shown are of course possible within the
scope of the invention, especially as regards the shape and placement of the openings
in the valve cover and in the constriction disk. Furthermore, the range hood can,
in one variation, be provided with a mechanism, by means of which the sliding shutter,
in the closed position of the valve, can be adjusted from outside the range hood.
It is also possible to make the valve cover and the sliding shutter with interaction
projections and cavities for indicating various displacement positions for the sliding
shutter relative to the valve cover, and a clamping mechanism can be arranged to keep
the sliding shutter in the said position.
1. Valve for controlling the ventilation flow from a kitchen range hood, comprising
means (8), which permit a basic flow of ventilation air to pass through the valve
when in its closed position, characterized in that the valve has an opening (8, 9),
the area of which is adjustable.
2. Valve according to Claim 1, characterized in that a sliding shutter (9), which
is slideably displaceable on a valve cover (1), more or less covers a through opening
(8) in the valve cover depending on its displacement position.
3. Valve according to one of Claims 1 and 2, characterized in that the valve cover
(1) is hinged to the end (5) of a pipe stub (3) and that the valve (1), in the closed
position of the valve, covers the end opening of the pipe stub (3).
4. Valve according to one of Claims 1-3, characterized in that a constriction disk
(2) is arranged in the pipe stub (3) in the same end portion which cooperates with
the valve cover (1), said constriction disk having a constriction opening (6).
5. Valve according to Claim 4, characterized in that the valve cover (1) on the side
facing the pipe stub (3) comprises a projection portion which contains the opening
(8) and which extends, in the closed position of the valve, through the opening (6)
in the constriction disc (2).
6. Valve according to one of Claims 1-5, characterized in that a metering outlet (12)
is arranged in the pipe stub (3) to permit measurement of the pressure drop over the
valve.
7. Valve according to Claim 6, characterized in that the metering outlet (12) consists
of a tube open at both ends, which extends from a position upstream of the valve cover
(1) end opening interacting with the pipe stub (3) through the wall of the pipe stub
(3) and opens into the interior of the pipe stub downstream of the constriction disk
(2).
8. Valve according to one of Claims 1-7, characterized in that a scale (11) is arranged
to show the size of the opening, through which the basic flow of ventilation air passes.