FR2772465A1 - WATER-CONTROLLED HOT WATER GENERATOR - Google Patents

Abstract

The invention relates to a hot water generator which comprises means (8) for restricting a cold water inlet pipe separating this pipe into an upstream section (9) and into a downstream section (10) , and a fuel supply (15) which delivers a quantity of fuel subject to the passage of cold water in the pipe (2). The restriction means (8) comprise at least one valve (35) comprising a seat (38), a closure member (39) movable between a closed position in which the member abuts against the valve seat and a position open in which said member is released from said seat, the valve having a shape adapted to create a pressure drop proportional to the flow of water passing through the seat, and an orifice (37) for permanent communication between the upstream section and the downstream section .

Description

WATER-CONTROLLED HOT WATER GENERATOR

  The present invention relates to a hot water generator and in particular to a domestic hot water generator. An example of a commonly encountered hot water generator is shown diagrammatically in FIG. 1. This type of hot water generator usually comprises: - a cold water inlet pipe 2 connected to a cold water circuit 3; - a hot water outlet pipe 4 connected to a hot water circuit 5; - a heat exchanger 6 interposed between the cold water circuit 3 and the hot water circuit 5; - A fluid fuel burner 7 transferring heat to the heat exchanger 6; restriction means 8 of the cold water inlet pipe 2 separating this pipe 2 into an upstream section 9 and a downstream section 10 and causing, during the passage of cold water, a pressure difference between the upstream section 9 and the downstream section 10; an enclosure 11il divided, by a displaceable element 12, into an upstream chamber 13 and a downstream chamber 14, the upstream chamber 13 being subjected to the pressure prevailing in the upstream section 9 of the cold water inlet pipe 2, and the downstream chamber 14 being subjected to the pressure prevailing in the downstream section 10 of the cold water inlet pipe 2, said element 12 being displaceable under the pressure difference existing between said two upstream chambers 13 and downstream 14; and a supply 15 of fluid fuel which delivers a quantity of fuel subject to the passage of cold water in the cold water inlet pipe 2 by means of the displacements of said displaceable element

12.

  This hot water generator is a hot water generator with variable power insofar as there is a progressive opening of the supply 15 of fluid fuel as a function of the water flow rate passing through the cold water inlet pipe. 2. The fuel flow is proportional to the water flow in order to have an elevation of

  constant temperature at the device outlet.

  In this type of hot water generator, the restriction means comprise a Venturi 16 to which the downstream chamber 14 is connected and upstream of which is a selector

temperature 17.

  This temperature selector 17 comprises a head 18 intended to completely or partially block the upstream section 9 of the cold water inlet pipe 2. The head 18 is crossed by a passage 19 intended to allow a certain flow d even in the closed position of this

temperature selector.

  The temperature selector 17 is manually adjustable-

  in order to vary the water flow through the

Venturi 16.

  When the selector 17 is in the open position (shown in dashed lines), it is the Venturi 16 which ensures the pressure difference between the upstream chamber 13 and the downstream chamber 14 of the enclosure 11 and consequently the deformation of the movable element 12 driving

opening the power supply 15.

  When the selector 17 is in the closed position (shown in solid lines), said pressure difference obtained on the displaceable element is mainly due to the circulation of fluid in the through passage 19. The temperature selector with manual adjustment makes it possible to give a user the choice of the flow rate for drawing hot water and / or the desired temperature according to the need for water. Thus, when the temperature selector is closed, the water flow in the exchanger is much lower than the water flow when the selector is in the open position and consequently, a much higher temperature rise is obtained. However, the setting of the opening of the temperature selector defines the maximum water flow through the exchanger 6. Also, with this type of generator, it is

  impossible to reach maximum water flow without reinterpreting

  come to the selector position setting. Therefore, for a given position, the range of values

flow is reduced.

  In addition, when the selector is opened wide while the user draws only a small flow, it is impossible to obtain hot water since the

  pressure difference created is insufficient.

  The object of the present invention is to remedy the drawbacks mentioned above by providing a hot water generator in which the adjustment of the water flow rate is directly controlled by the drawing, in a range of values of the increased water flow rate, and with a constant rise in temperature within the limit of

power of the device.

  To this end, according to the invention, a hot water generator of the aforementioned type, is essentially characterized in that the restriction means comprise: - at least one valve comprising a valve seat, - a closure member movable between a closed position in which the member is in abutment against the valve seat and an open position in which said member is released from said valve seat, the valve having a shape adapted to create a pressure drop proportional to the flow of water passing through the valve seat, and - a permanent communication orifice between the upstream section and the downstream section of the inlet pipe

of cold water.

  The hot water generator according to the invention may optionally further include one or more of the following characteristics: the closing member of said at least one valve is of hemispherical shape and is mounted movably on a compression spring of predetermined stiffness, the valve seat being of shape complementary to that of the closure member; the restriction means comprise a single valve; - The restriction means comprise a first and a second valve mounted respectively on a first and a second compression spring, the first compression spring being of stiffness greater than that of the second spring so that the second valve opens before the first valve ; - the upstream section of the inlet pipe includes a flow limiter; - a bypass pipe is attached to the cold water inlet pipe, a first end of this pipe being connected to the upstream section of said cold water inlet pipe and a second end of said pipe is connected to the downstream section of said inlet pipe; - The bypass conduit includes closing means with manual control; - A through passage is formed between the upstream section and the downstream section, this passage comprising shutter means with manual control; - the assembly including the upstream section, the means

  and the downstream section forms a modular element

  the area that can be attached in one piece to the hot water generator or separated from it; - The communication orifice is formed in at least one of the movable closing members; and - the hot water generator is a water generator

domestic hot water.

  Three embodiments of the invention will now be described with reference to the accompanying drawings, in which:

  - Figure 1 is a schematic view of a general-

  hot water according to the state of the art; - Figure 2 is a schematic view of a first embodiment of a hot water generator according to the present invention; - Figure 3 is a schematic view of a second embodiment of a hot water generator according to the invention; - Figure 4 is a graph showing the opening of the fluid fuel supply as a function of the water flow rate requested by the user; and - Figure 5 is a schematic view of a third embodiment of a hot water generator according to

the invention.

  Figure 1 shows a hot water generator

  according to the state of the art which has already been described previously

  is lying. Some of the components of the hot water generator 1 according to the present invention and shown

  in Figure 2 are identical to the generator in Figure 1.

  These common elements will have the same reference.

  Thus, the hot water generator 1 comprises, in a manner known per se, a cold water inlet pipe 2 connected to a cold water circuit 3, an outlet pipe

  hot water 4 connected to a hot water circuit 5, a heat exchanger

  heat sink 6 interposed between the cold water circuit 3 and the hot water circuit 5 and below which is a burner 7 with fluid fuel. This fuel is by

example of natural gas.

  The burner 7 is supplied with gas by means of a supply 15 which delivers a quantity of fuel controlled by the passage of cold water in the cold water inlet pipe 2. For reasons of clarity, only the components of this supply 15 necessary for understanding the invention have been shown, this is why the part of the power supply 15 connected to the burner

7 has not been shown.

  This supply 15 consists of a conduit 20 comprising an inlet 21 through which the gas arrives and an outlet 22 intended to be connected to the burner 7. The inlet 21 is closed by a valve 23 which comprises a valve seat 24, a valve head 25 and a valve stem 26 connected to said head 25. The valve head 25 is urged to bear against the valve seat 24 by a compression spring 27, this spring resting on a shoulder 28 formed

in conduit 20.

  The hot water generator 1 further comprises an enclosure 11 divided, by a movable element 12, into a

  upstream chamber 13 and a downstream chamber 14. The element displaces

  cable 12 is for example a membrane made of deformable material and produced by molding. The end of the rod 26 opposite to that connected to the valve head 25, is integral with this

  displaceable element 12 or resting thereon.

  Over a part of its length, the cold water inlet pipe 2 comprises restriction means 8 which separate this pipe into an upstream section 9 and into a downstream section 10. These restriction means cause, during the passage of cold water in the direction of arrow F in line 2, a pressure difference between said section

upstream 9 and said downstream section 10.

  The upstream chamber 13 of the enclosure 11 is connected to the cold water inlet pipe 2, upstream of said restriction means 8, by a pipe 30. The downstream chamber 14 of the enclosure 11 is connected to the pipe input 2, downstream

  said restriction means 8, via a conduit 31.

  The pressure difference created by the restriction means 8 between the upstream section 9 and the downstream section 10 of this pipe causes the same pressure difference

  between the upstream 13 and downstream 14 chambers of the enclosure 11.

  This pressure difference therefore applies to the displaceable element 12 which deforms, during the passage of cold water 2, towards the upper part of the enclosure 11 and causes, in its movement, the displacement of the rod. valve 26. This rod releases the valve head 25 from its seat 24, against the action of the compression spring 27. Gas then flows in the conduit 20 in the direction of the

burner 7.

  It is therefore understood that the fuel supply 15

  ble fluid delivers a quantity of fuel to the burner 7 which is slaved to the passage of cold water in the cold water inlet pipe 2 via the displacements

of said movable element 12.

  In the first embodiment of the invention, the restriction means 8 comprise a valve 35 thus

  a partition 36 crossed by an orifice 37.

  The valve 35 consists of a valve seat 38, a movable closure member 39 and a compression spring 40 on which the closure member 39 is mounted. The orifice 37 is a permanent communication orifice between the upstream 9 and downstream 10 section of the pipe

cold water inlet 2.

  As a variant, the orifice 37 is formed in the member

movable closure 39.

  During a drawing, cold water enters in the direction of the arrow F in the inlet pipe 2 and pushes the closing member 39 against the spring 40. The valve 35 opens more or less as a function of the water flow rate in the inlet pipe, which causes, in combination with the orifice 37, a more or less strong depression between the upstream section 9 and the downstream section 10 and therefore between the upstream chambers 13 and downstream 14 of the enclosure 11. This

  depression causes the valve stem 26 to lift.

  Curve B of the graph in FIG. 4 shows the proportionality between the flow admitted into the inlet pipe 2 and the lifting of the valve stem 26. It is thus understood that according to the stiffness of the compression spring 40, the slope of the curve B, at the start of the drawing, is more or less strong. We also note that, as long as the maximum admissible water flow rate by the generator is not reached, it is not the construction architecture of this generator which limits the water flow rate, but the user who has need more or less hot water. In addition, the temperature rise is constant within the limit of the power of the generator, and beyond, the temperature rise decreases to a value dependent on the maximum water flow of the

generator.

  In this embodiment, the closing member 39 of the valve 35 is of hemispherical shape and abuts on the valve seat 38 of complementary shape. However, it is understood that depending on the shape of the desired curve B, the valve can have a different shape in combination with

  a spring with characteristics (preload, stiffness) predeter-

  mined, to create a pressure drop linked to the water flow through the valve seat 38 linked by a law of proportionality different from that illustrated by the curve

B.

  The comparison of curve B with curve A (representative of the generator described with reference to FIG. 1) shows that the generator according to the present invention makes it possible to obtain ranges of flow values more

important.

  The permanent orifice 37 makes it possible, with respect to the generator of FIG. 1, to decrease the flow of cold water in the inlet pipe 2 to cause movement of the valve stem 26. The user thus obtains water

hot at lower flow.

  Furthermore, the upstream section 9 of the cold water inlet pipe 2 has a flow limiter 41 which makes it possible to calibrate the maximum cold water flow. It will be noted, for reasons of clarity, that this flow limiter has not been shown on the same scale as the valve 35 and

orifice 37.

  The hot water generator 1 further comprises a bypass duct 42 mounted on the cold water inlet pipe 2. A first end 43 of this duct 42 is connected to the upstream section 9 of this pipe 2 and a second end 44 of the duct 42 is connected to the downstream section 10. Manually controlled closing means 45 are mounted on this bypass duct 42. These means take

  for example the shape of a tap actuated by a user

  tor. The opening or closing of this tap allows cold water to be admitted from the upstream section 9 to the downstream section 10 without this quantity of cold water being subjected

  a pressure drop due to the restriction means 8.

  The user therefore opens the tap 45 when he wishes that, for the same quantity of hot water drawn, the pressure drop created is lower and therefore the lifting of the lower valve stem 26, thus making it possible to reduce the temperature rise for the same water flow. The second embodiment of the generator according to the present invention, represented in FIG. 3, differs from the first embodiment only by the number of valves constituting the restriction means 8. Also, the constituent elements common to the two embodiments

will bear the same references.

  The restriction means 8 of the inlet pipe 2 now have a second valve 50 placed adjacent to the first valve 35. This second valve has a compression spring 51 whose stiffness and

  the preload is lower than the first compression spring

  sion 40 of the first valve 35. It also has a closure member 53 intended to abut against a valve seat 52 whose diameter is less than the first seat of

valve 38 of the first valve 35.

  As a variant, the communication orifice 37 is formed in at least one of the two closing members

mobiles 39 and 53.

  In the generator drawing position, the second valve 50 opens before the first valve 35. The first valve 35 opens when the water flow increases in the

inlet line 2.

  Thus, the pressure drop caused by these two valves increases much more gradually than in the first embodiment. This gives rise to the valve stem 26 more proportional to the admitted water flow. Ideally, a line is obtained which is substantially identical to the curve C shown in the

figure 4.

  Alternatively, the valves 35 and 50 could be held, not by compression springs, but by springs working in tension or even by

  deformable elements integrated directly into these valves.

  The third embodiment shown in Figure 5 differs from the first embodiment in Figure

  2 only by the implantation of the bypass duct 42.

  This duct takes the form of a through passage 60 formed in the partition 36. A first end 61 of this passage opens into the upstream section 9 of the cold water inlet pipe 2 and a second end 62 of the passage 60 opens in the downstream section 10. In this second end 62 is placed a tap 63 which can be controlled by a user to more or less close the through passage 60. The function of this passage 60 is the same as that of the bypass duct 42 described in look of the

figure 2.

  Furthermore, the flow limiter 41 is placed in the upstream section 9, as close as possible to an area close to the duct 30 and the restriction means 8. A water filter 64 is placed in the section 9, upstream of the limiter of

  flow 41 and in the vicinity thereof.

  The assembly thus constituted by the upstream section 9, the restriction means 8 and the downstream section 10 forms a compact module which can be easily attached to the hot water generator or separated from it. This module can therefore be delivered tested and maintenance is easy. Of course, the module described above can also be adapted to the second embodiment of the

figure 3.

Claims (11)

  1. Hot water generator comprising: - a cold water inlet pipe (2) connected to a cold water circuit (3); - a hot water outlet pipe (4) connected to a hot water circuit (5); - a heat exchanger (6) interposed between the cold water circuit (3) and the hot water circuit (5); - a burner (7) with fluid fuel transferring heat to the heat exchanger (6); - restriction means (8) of the cold water inlet pipe (2) separating this pipe (2) into an upstream section (9) and a downstream section (10) and causing, during the passage of water cold, a pressure difference between the upstream section (9) and the downstream section (10);   - an enclosure (11) divided by a displaced element   cable (12), in an upstream chamber (13) and a downstream chamber (14), the upstream chamber (13) being subjected to the pressure prevailing in the upstream section (9) of the cold water inlet pipe ( 2), and the downstream chamber (14) being subjected to the pressure prevailing in the downstream section (10) of the pipe   cold water inlet (2), said element (12) being displaced   ble under the pressure difference existing between said two upstream (13) and downstream (14) chambers; and - a supply (15) of fluid fuel which delivers a quantity of fuel subject to the passage of cold water in the cold water inlet pipe (2) by means of the displacements of said displaceable element (12),   characterized in that the restriction means (8) comprise: - at least one valve (35; 50) comprising a valve seat (38; 52), - a movable closure member (39; 53) between a closed position in which the member (39; 53) abuts against the valve seat (38; 52) and an open position in which said member (39; 53) is released from said valve seat (38; 52), the valve ( 35; 50) having a shape adapted to create a pressure drop proportional to the water flow which passes through the valve seat, and - an orifice (37) of permanent communication between the upstream section (9) and the downstream section (10 ) of conduct cold water inlet (2).   2. Hot water generator according to claim 1, characterized in that the closure member (39; 53) of said at least one valve (35; 50) is of hemispherical shape and is movably mounted on a compression spring ( 40; 51) of predetermined stiffness, the valve seat (38; 52) being of a shape complementary to that of the closure member (39; 53).   3. Hot water generator according to claim 2,   characterized in that the restriction means (8) comprise only one valve (35).   4. Hot water generator according to claim 2,   characterized in that the restriction means (8) comprise   a first (35) and a second (50) valves mounted respectively on a first (40) and a second (51)   compression springs, the first (40) compression spring   sion being of stiffness greater than that of the second spring (51) so that the second valve (50) opens before the first valve (35).   5. Hot water generator according to any one   of claims 1 to 4, characterized in that the section   upstream (9) of the inlet pipe (2) includes a limiter debit (41).   6. Hot water generator according to any one   claims 1 to 5, characterized in that a   bypass (42) is attached to the cold water inlet pipe (2), a first end (43) of this pipe (42) being connected to the upstream section (9) of said cold water inlet pipe (2) and a second end (44) of said duct (42) is connected to the downstream section (10) of said inlet pipe (2).   7. Hot water generator according to claim 6, characterized in that the bypass duct (42) comprises closing means with manual control (45). 8. Hot water generator according to any one   claims 1 to 5, characterized in that a passage   through (60) is formed between the upstream section (9) and the downstream section (10), this passage (60) comprising means   manually operated shutter (63).   9. Hot water generator according to any one   of claims 1 to 8, characterized in that the assembly   comprising the upstream section (9), the restriction means (8) and the downstream section (10) forms a modular element which can be attached in one piece to the water generator   hot or separated from it.   10. Hot water generator according to any one   claims 4 to 9, characterized in that the orifice   communication (37) is arranged in at least one of the organs mobile closing devices (39; 53).   11. Hot water generator according to any one   claims 1 to 10, characterized in that the general   hot water generator (1) is a domestic hot water generator.