FLOW CONTROL FOR A CONTINUOUS-FLOW WATER HEATER

PIECE DE ROBINETTERIE POUR UN CHAUFFE-EAU INSTANTANE

English Abstract

The aim of the invention is to devise a flow control for a continuous-flow water heater, which is used to control the flow of gas to a burner of a heat exchanger as a function of the passage of water, in which only one operating element has to be actuated. Because of the reduction in the apertures through the housing wall of the flow control, at the same time the risk leaks occurring is reduced. Furthermore, the expenditure in manufacturing is to be minimized. To this end, in addition to the operating element (8), a switching element (9) is rotatably mounted on a spindle (7) projecting from the water-carrying housing (5), wherein a rotary movement of the operating element (8) can be transmitted via drivers (10; 11) to the switching element (9), which also has a switching contour (13) by means of which a fixedly arranged microswitch (14) can be actuated, by means of which an electronic ignition and monitoring device (3) can be electrically actuated, by means of which gas flow to the burner can be shut off.

French Abstract

L'objet de l'invention est d'obtenir une pièce de robinetterie pour un chauffe-eau instantané, servant à commander le flux du gaz jusqu'à un brûleur d'un échangeur de chaleur, en fonction du débit de l'eau, et dans laquelle seul un élément de commande doit être actionné. La diminution de la dimension des ouvertures ménagées dans la paroi de boîtier de la pièce de robinetterie permet de réduire le risque d'apparition de fuites. L'objet de l'invention est également d'obtenir une simplification de la fabrication. A cette fin, en plus de l'élément de commande (8), un élément de commutation (9) est monté rotatif sur une broche (7) qui fait saillie hors du boîtier à circulation d'eau (5). Un mouvement rotatif de l'élément de commande (8) peut être transmis par des entraîneurs (10;11) à l'élément de commutation (9) qui comporte un profilé de commutation (13) par l'intermédiaire duquel un microcommutateur (14) monté fixe peut être actionné, ce microcommutateur (14) permettant de commander électriquement un dispositif d'allumage et de surveillance électronique (3) permettant d'arrêter le flux de gaz vers le brûleur.

Claims

9
Claims
1. Flow control for a continuous-flow water heater, comprising a water part
(1)
controlling the passage of water to a heat exchanger wherein the quantity of
water can be manually set by an operating element (8) attached to a spindle
(7) projecting from the water-carrying housing (5), a gas part (2) with an
elec-
tronic ignition and monitoring device (3) controlling the gas flow as a
function
of the passage of water to an atmospheric burner, and a mechanical trans-
mission which transmits, as a function of the passage of water and, prefera-
bly in each case by means of a Venturi nozzle housed in the water-carrying
housing and a membrane, a steering movement initially from the interior of
the water-carrying housing (5) to the exterior and then from there into the
gas-carrying housing (6) to a valve controlling the amount of gas, character-
ised in that a switching element (9) is rotatably mounted on the spindle (7),
wherein a rotary movement of the operating element (8) can be transmitted
by driver (10;11) to the switching element (9), and that the switching element
(9) has a switching contour (13), by means of which a fixedly arranged mi-
croswitch (14) can be actuated which shuts off the gas flow to the burner by
means of the electronic ignition and monitoring device (3) and an electrically
actuatable valve.
2. Flow control for a continuous-flow water heater according to claim 1,
charac-
terised in that the electrically actuatable valve is formed by the servo valve
of the electronic ignition and monitoring device (3).
3. Flow control for a continuous-flow water heater according to claim 1 or
2,
characterised in that the driver (10;11) is formed by one or a plurality of
ribs
(10) located on the operating element (8) and projecting into slots (11) lo-
cated on the switching element (9).

10
4. Flow
control for a continuous-flow water heater according to one or several of
the claims 1 to 3, characterised in that the switching element (9) is con-
nected to the operating element (8) by locking hooks (12).

Description

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Description
Flow control for a continuous-flow water heater
Technical field of the invention
The invention relates to a flow control for a continuous-flow water heater
according
to the preamble of the first claim.
Prior art
Flow controls of this type for continuous-flow water heaters are available in
a very
wide range of designs. They serve to control the gas flow rate to a burner of
a heat
exchanger as a function of the passage of water.
For example, a gas valve for a burner-heated water heater with a main gas
valve
on the inlet side connected to a flow meter is described in DE 198 25 046 Al,
a
German patent application open to public inspection. A water deficiency valve,
which is connected to the flow meter, is located downstream of the main gas
valve.
A thermostatically controlled valve connected to an evaluation circuit is in
turn lo-
cated downstream of the water deficiency valve. When the water heater is in op-
eration, both the water flow rate and the temperature of the hot water flowing
off
can be set by means of two operating elements.
A gas-heated continuous-flow water heater with a heat exchanger heated by a
burner is known from EP 1 170 549 A2. A water valve in a water switch is
located
upstream of the heat exchanger and gas valves, one of which is controlled by a
water switch and another by a gas pressure-controlled servo valve, are located
upstream of the heat exchanger on the gas side. Whereas an adjusting valve
downstream of the gas valve on the gas side is actuated by a first handle and
the
gas valve is controlled by the servo valve, the water valve can be actuated by
a
second handle.

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A gas-heated continuous-flow water heater, which is described in DE 100 30 118
= Al, a patent application open to public inspection, has a similar
structure. This de-
vice also has two handles for operating the continuous-flow water heater.
A water heater, which has two operating elements, in this embodiment a control
button and an ignition button, is also described in the Austrian patent
specification,
= AT 406 611 B.
A disadvantage common to these flow controls is that in order to switch the
con-
lo tinuous-flow water heater on and off or to set the required operating
parameters,
such as water temperature and water quantity, two separate operating elements
are required for which corresponding apertures in the outer wall of the flow
control
must be made and therefore sealed as well of course. Furthermore, this makes
the
structure of the device and its operation by the user more complicated.
Summary of the invention
The invention addresses the problem of ensuring that a flow control for a
continu-
ous-flow water heater according to the preamble of the first claim can be
operated
easily and in a user-friendly manner by reducing to just one the number of
operat-
ing elements that need be actuated. At the same time, the risk of leaks
occurring is
reduced because of the reduction in the number of apertures through the
housing
wall of the flow control. Furthermore, manufacturing costs are to be
minimised.
= 25 The problem is solved according to the invention in that, in
addition to the operat-
ing element, a switching element is rotatably mounted on the spindle
projecting
from the water-carrying housing, wherein a rotary movement of the operating
ele-
ment can be transmitted to the switching element by means of a driver. This
switching element has in addition a switching contour by means of which a
fixedly
arranged microswitch can be actuated. An electronic ignition and monitoring de-
vice by means of which the gas flow to the burner can be shut off by means of
an

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electrically actuated valve can be electrically actuated by means of this mi-
croswitch.
A solution was therefore found which eliminated the disadvantages in the prior
art
referred to above. The manual activation of only a single operating element
makes
it possible to manually shut down and start up the continuous-flow water
heater as
well as to adjust the water flow rate to a preset value corresponding to the
supply
conditions, or to manually compensate for fluctuations in the cold water
tempera-
ture.
Advantageous embodiments of the invention are set out in the dependent claims.
An advantageous embodiment of the flow control for reducing manufacturing
costs
even further has proved to be a flow control in which the valve serving to
shut off
the gas flow by means of the operating element is formed by the servo valve
form-
ing part of the electronic ignition and monitoring device.
The rotary movement of the operating element can be transmitted simply and
=
safely to the switching element by forming the driver by one or a plurality of
ribs
located on the operating element and projecting into slots located on the
switching
element.
In order to ensure operating element and switching element are securely fixed
in a
longitudinal direction it is advantageous if the switching element is
connected to
the operating element by locking hooks.
Execution example
The flow control according to the invention for a continuous-flow water heater
is
explained below in more detail by means of an execution example with the aid
of
diagrams which show:

t =
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Fig. 1 an embodiment of a flow control for a continuous-flow water heater in
the
switched off state,
Fig. 2 a view A of the flow control for a continuous-flow water heater from
Fig.1 in
the switched off state,
Fig. 3 a view B of the flow control for a continuous-flow water heater from
Fig.2 in
the switched on state,
Fig. 4 a view C of the flow control for a continuous-flow water heater from
Fig.3 in
the switched on state.
The exemplary flow control according to the invention for a continuous-flow
water
heater shown in the diagrams serves to control the gas flow rate to a burner
of a
heat exchanger (not illustrated) as a function of the passage of water. In
this exe-
cution example the burner comprises a pilot burner (not illustrated) and a
main
burner (also not illustrated).
The flow control comprises:
= = a water part 1 controlling the passage of water to the heat exchanger,
= a gas part 2 controlling the gas flow to the burner as a function of the
passage
of water,
= an electronic ignition and monitoring device 3.
A regulating valve and a main valve are housed in the gas part 2 in addition
to
other components which are known to a person skilled in the art and are
therefore
not explained in more detail here. The main valve is actuated by an electronic
igni-
tion and monitoring device 3, also known as a so-called automatic firing
device,
which is connected to the gas part 2 and is also known to a person skilled in
the
' art.
The regulating valve is actuated by a transmission 4 which transmits the move-
ment as a function of the passage of water of a water membrane located in the
water part 1 from the interior of the water-carrying housing 5 to the exterior
and

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then from there into the gas-carrying housing 6 of the gas part 2 to the
regulating
valve.
In addition, a Venturi nozzle and a pre-setting element, which enables the
water
flow rate to be set to a preset value corresponding to the supply conditions,
are
5 also located in the water-carrying housing 6, in addition to other
components
which are known to a person skilled in the art and are therefore not explained
in
more detail either. This pre-setting element serves at the same time as a
tempera-
ture corrector, i.e. it enables fluctuations in the cold water temperature to
be
manually compensated.
To enable manual actuation a spindle 7, which is connected to the pre-setting
element and to which an operating element 8 is attached, projects from the
water-
carrying housing 5. In addition to the operating element 8 a switching element
9 is
rotatably mounted on the spindle 7 projecting from the water-carrying housing
5,
wherein a rotary movement of the operating element 8 can be transmitted by a
driver to the switching element 9.
In this execution example the driver is advantageously formed by a plurality
of ax-
ial ribs 10 which are located on the operating element 8 and extend into axial
slots
11 assigned to them and located on the switching element 9. In order to
addition-
ally ensure the switching element 9 is fixed in the longitudinal direction of
the spin-
dle 7, operating element 8 and switching element 9 have locking hooks 12
facing
each other which ensure a reliable connection.
The switching element 9 has in addition a switching contour 13 by means of
which
a microswitch 14 fixedly arranged on the gas-carrying housing 6 in this
execution
example can be actuated. The microswitch 14 is electrically connected to the
elec-
tronic ignition and monitoring device 3.
The flow control for a continuous-flow water heater illustrated in the
diagrams has
the following mode of operation:

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Figs 1 and 2 show an embodiment of a flow control according to the invention
for a
6 continuous-flow water heater in the switched off state. The
operating element 8 is
:
in the off-position. In this position the switching element 9 has been turned
until the
switching contour 13 has exposed the button 15 of the microswitch 14. The gas
s supply to the burner is thereby shut off by means of the electronic
ignition and
monitoring device 3 and the continuous-flow water heater remains switched off
whether or not water is drawn off from a water tap downstream of the
continuous-
flow water heater.
io In order to switch on the flow control the operating element 8 must be
turned until
it is in the possible setting range for adjusting the water flow rate or for
manually
compensating for fluctuations in the cold water temperature, as shown for
example
in Figs. 3 and 4.
is As soon as water is then drawn from a downstream water tap, the gas
inlet to the
burner of the heat exchanger is opened by means of the electronic ignition and
= monitoring device 3 and the gas is ignited. The burner remains in
operation until
,
no more water is drawn off. However, the continuous-flow water heater remains
ready for operation and can be re-started when water is drawn off again.
In order to switch off the continuous-flow water heater manually the operating
ele-
ment is moved into the off-position through the possible setting range for
setting
the water flow rate, as shown in Figs. 1 and 2. As already explained in more
detail
above, the gas supply to the burner is thereby shut off whether or not water
is
= 25 drawn off.
. The flow control according to the invention for a continuous-
flow water heater is
= not of course restricted to the execution example depicted. On the
contrary, modi-
fications, variations and combinations can be made without departing from the
=
scope of the invention.

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In order to prevent the off-position being inadvertently set when the required
water
flow rate is to be set or when fluctuations in the cold water temperature are
to be
manually compensated, it has, for example, proved to be advantageous if the
off-
position cannot be reached until a detent is overcome which indicates the end
of
the setting range but beyond which the operating element can be turned.

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List of reference numerals
1 Water part
= 2 Gas part
3 Ignition and monitoring device
4 Transmission
5 Water-carrying housing
= 6 Gas-carrying housing
= 7 Spindle
= 8 Operating element
9 Switching element
Rib
11 Slot
12 Locking hooks
13 Switching contour
14 Microswitch
Button

Representative Drawing