Abstract:
A diverter valve comprises a valve body defining first ( 1 ), second ( 5 ) and third ( 9 ) inlets and first ( 3 ) and second ( 7 ) outlets. A passage between the first inlet and the first outlet and first ( 11 ) and second ( 13 ) interconnected valve members within the valve body, the valve members being jointly movable between first and second positions. In the first position, fluid is able to pass from the first inlet to the second outlet and from the third inlet to the first outlet, the passage between the first inlet and the first outlet being closed. In the second position, fluid is able to pass from the second inlet to the second outlet and along the passage from the first inlet to the first outlet.

Description:
[0001]    This invention relates to a diverter valve and to a heating system employing such a valve. 
       BACKGROUND TO THE INVENTION 
       [0002]    New technology in water heating, such as heat pumps, can significantly improve the cost efficiency of heating buildings and/or providing hot water. Although installation into a new building is straightforward, fitting such technology to existing buildings is troublesome. In order to keep costs to a minimum it is generally necessary to retain an existing boiler and heating system and the new technology is required to provide a secondary source of relatively higher efficiency heating. 
       OBJECT OF THE INVENTION 
       [0003]    It is therefore an object of the present invention to provide a diverter valve which overcomes, or at least ameliorates, the above problems and a heating system incorporating such a diverter valve. 
       SUMMARY OF THE INVENTION 
       [0004]    According to one aspect of the present invention there is provided a diverter valve comprising: 
         [0000]    a valve body defining first, second and third inlets and first and second outlets and a passage between the first inlet and the first outlet; and
 
first and second interconnected valve members within the valve body, the valve members being jointly movable between first and second positions,
 
wherein, in the first position, fluid is able to pass from the first inlet to the second outlet and from the third inlet to the first outlet, the passage between the first inlet and the first outlet being closed, and, in the second position, fluid is able to pass from the second inlet to the second outlet and along the passage from the first inlet to the first outlet.
 
         [0005]    The second inlet may be closed in the first position of the valve members. 
         [0006]    The valve may include a passage between the first inlet and the second outlet, the passage being closed in the second position of the valve members. 
         [0007]    The valve may include an injector in the second inlet. 
         [0008]    The valve may include means, such as a coil spring, for biasing the valve members to the first position. 
         [0009]    The valve members may be interconnected by a shaft. 
         [0010]    One of the valve members may be positioned between the second inlet and the second outlet, the valve member being substantially conical, for example for sealing with the injector. 
         [0011]    The valve members may be movable between the first and second positions by fluid pressure, for example solely by fluid pressure. 
         [0012]    Alternatively or additionally, the valve may include actuating means for moving the valve members between the first and second positions. The actuating means may comprise a solenoid or a thermostatic device. Where the thermostatic device is provided, a by-pass may be provided in the second inlet to allow flow of (a relatively small amount of) fluid. 
         [0013]    The valve members may be provided within a cartridge which may be, for example, cylindrical. 
         [0014]    The valve members may be in the form of plate members which are movable in a linear manner, for example in a direction substantially perpendicular to the plane thereof. Alternatively, the valve members may be in the form of flap members which are pivotal about an edge region thereof. 
         [0015]    A sealing member may be provided in a peripheral region of the valve members. The sealing member may be elastomeric material, for example rubber. 
         [0016]    According to another aspect of the present invention there is provided a heating system including a diverter valve as hereinbefore defined, a primary source of heating fluid, a secondary source of heating fluid, and a fluid distribution circuit, the secondary source being connected to the first inlet and the first outlet, and the primary source being connected to the second inlet and the third inlet, and the fluid distribution system being connected to the second outlet and the third inlet. 
         [0017]    The primary source of heating fluid may comprise a source of relatively high-temperature fluid and the secondary source of heating fluid may comprise a source of relatively low-temperature fluid. 
         [0018]    The primary source of heating fluid may comprise a conventional heating boiler. 
         [0019]    The secondary source of heating fluid may comprise a heat pump, such as an air source heat pump. 
         [0020]    The fluid distribution circuit may comprise a hot water and/or a heating circuit. 
         [0021]    For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a diagrammatic cross-sectional view of one embodiment of a diverter valve according to the present invention; 
           [0023]      FIG. 2  is a diagrammatic cross-sectional view of another embodiment of a diverter valve according to the present invention provided with biasing means; 
           [0024]      FIG. 3  is a diagrammatic cross-sectional view of a modification of the diverter valve shown in  FIG. 2 ; 
           [0025]      FIG. 4  is a diagrammatic cross-sectional view of another embodiment of a diverter valve according to the present invention provided with actuating means; 
           [0026]      FIG. 5  is a diagrammatic cross-sectional view of an alternative modification of the diverter valve shown in  FIG. 2 ; 
           [0027]      FIG. 6  is a diagrammatic cross-sectional view of a further embodiment of a diverter valve according to the present invention, provided with flap valve members; 
           [0028]      FIG. 7  is a diagrammatic cross-sectional view of another embodiment of a diverter valve according to the present invention provided with actuating means in the form of a liquid expansion device; and 
           [0029]      FIG. 8  is a diagrammatic illustration of a heating system according to the present invention incorporating a diverter valve. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0030]    The diverter valve shown in  FIG. 1  is adapted to control the directional movement of fluid for separately connecting primary and secondary heating fluid sources to a single output. The secondary heating fluid source is generally a relatively low-temperature source, such as a heat pump, especially an air source heat pump, and the primary heating fluid source is generally relatively high-temperature source, such as a boiler. 
         [0031]    The valve has a body including a first inlet  1  for fluid, such as water, from a secondary heating fluid source, and an adjoining first outlet  3  for returning the (relatively low-temperature) fluid to its source, the inlet and outlet being interconnected by a flow path through the valve. The valve body also includes a second inlet  5  for fluid, such as water, from a primary heating fluid source, the inlet including an injector  6  for providing a relatively high flow rate of fluid exiting the injector. 
         [0032]    The valve body has a second outlet  7  for connection to a fluid distribution circuit, for example a hot water system, such as a domestic hot water system, and a third inlet  9  for connection to returning fluid from the fluid distribution circuit. The outlet  7  is in fluid connection with both inlet  1  and inlet  5  and the inlet  9  is in fluid connection with the outlet  3 . 
         [0033]    Fluid flow through the valve is controlled by means of two valve members  11 ,  13  which are interconnected by a shaft  15 , such as a rod, and which seal against alternate pairs of valve seats  17 ,  19  and  21 ,  23  as a result of movement of the shaft  15  and the valve members  11 ,  13  between a first position and a second position. The valve members are in the form of plates which are movable in a direction substantially perpendicular to the plates, that is in the axial direction of the shaft. 
         [0034]    When only the secondary source is operating, the valve members are in their first position (moved to the right as shown in  FIG. 1 ) with valve member  11  seated against valve seat  19  and valve member  13  seated against valve seat  17 . In this configuration, (relatively low-temperature) fluid flows from inlet  1  to outlet  7  and through the fluid distribution circuit and returns through inlet  9  to outlet  3  to be further heated by the secondary source. In this way, when only the secondary source is operating, the fluid in the fluid distribution circuit is heated to a first (relatively low) temperature, but in a cost-effective way thereby providing preliminary heating for the overall system. 
         [0035]    When only the primary source is operating, the valve members are in their second position (moved to the left as shown in  FIG. 1 ) with the valve member  11  seated against valve seat  23  and valve member  13  seated against valve seat  21 . In this configuration, (relatively high-temperature) fluid flows from the inlet to the outlet  7 , while the inlet  9  is closed and returning fluid flows back to the primary source externally of the valve. 
         [0036]    The valve members  11 ,  13  may be moved between their first and second positions in any convenient way, including fluid pressure or a separate actuator means. Where the fluid from the primary source is at a higher pressure than the fluid from the secondary source, the valve members may be biased to the first position, for example by a coil spring  25  as shown in  FIG. 2 . In this way, when only the secondary source is operating the valve members are in their first position and when the primary source replaces the secondary source, the higher fluid pressure causes the valve members  11 ,  13  to move to their second position until the primary source is turned off, when the valve members return to the first position. 
         [0037]      FIG. 3  shows a modification of the valve shown in  FIG. 2  in which the valve member  13  and valve seats  17 ,  21  have a modified configuration and the coil spring  25  is in an alternative location. As can be seen from the figure, the valve member  13  is substantially conical and seats against the injector  6 . 
         [0038]      FIG. 4  shows an actuator  27  in the form of a solenoid which is connected to the shaft  15  by an extension shaft  29  for moving the valve members  11 ,  13  between the first and second positions in response to a control signal, for example a control signal switching between the secondary and primary sources. 
         [0039]      FIG. 5  shows an alternative modification of the valve shown in  FIG. 2  in which the valve members  11 ,  13 , shaft  15 , valve seats  19 ,  21  and spring  25  are mounted within a cartridge  31  which is constructed, for example with apertures (not shown) to provide minimal resistance to fluid flow. It will be noted the valve seats  17  and  23  have been omitted because they are not essential to the operation of the valve. 
         [0040]      FIG. 6  shows a modified version of the diverter valve in which the valve members  11 ,  13  are in the form of flap valves interconnected by shaft  15  and rotatable about hinges  37  in an edge region thereof. In this embodiment the valve seats  17  and  19  are modified to be sealed by the valve members  11 ,  13  when the valve members are inclined. If required, the valve members may be provided in a peripheral region thereof with seals  35  of elastomeric material, such as rubber. The diverter valve is shown in its first position in which the low-temperature source is operating with water flowing from the secondary source, through the valve and out of the outlet  7 , while returning water flows through the inlet  9  and through the outlet  3  back to the secondary heat source. Thus, the valve member  11  closes the path between the inlet  1  and outlet  3 . In the second position of the diverter valve, as shown in dashed lines in  FIG. 6 , water passes through the inlet  5  and injector  6  from the primary source and through the outlet  7  because the valve member  13  is sealed against the valve seat  21 , while returning water by-passes the inlet  9  because the valve member  11  is sealed against the valve seat  23 . 
         [0041]      FIG. 7  shows an actuator  27  in the form of a liquid expansion device connected to the shaft  15  by an extension shaft  29  for moving the valve members  11 ,  13  between the first and second positions. Liquid in the liquid expansion device expands in response to relatively hotter water from the primary source to move the valve members from the first position to the second position. In order to ensure the relatively hotter water reaches the liquid expansion device  27  a by-pass channel  33  is provided around valve seat  17  to allow a small flow of water when the primary source is turned on and before the valve members move to their second position. 
         [0042]    It should be noted that a liquid expansion device is only one form of thermostatic device that could be employed, including mechanical, electro-mechanical and electronic thermostatic devices which are well known to the skilled person. 
         [0043]      FIG. 8  shows a heating system incorporating a diverter valve  101  such as a diverter valve as described and shown in relation to  FIGS. 1 to 7 . The heating system includes a primary source, for example of relatively high-temperature fluid, in the form of a boiler  103 , such as a gas- or oil-fired boiler, a secondary source, for example of relatively low-temperature fluid, in the form of a heat pump  105 , such as an air source heat pump, and a fluid distribution circuit in the form of a conventional heating circuit  107  including, for example a hot water circuit and/or a heating circuit which may include conventional radiators. The boiler  103  and heating circuit  107  are commonly found in domestic premises, but are difficult to link to heat pump  105  in the absence of diverter valve  101 , especially when a buffer tank is not present as is the case with, for example, many heating systems incorporating condensing boilers. The boiler  103  is connected to inlet  5  of the valve and to inlet  9 , although fluid does not flow into the inlet  9  when the boiler is in use. The heat pump is connected to the inlet  1  of the valve and to the outlet  3 . The heating circuit is connected to the outlet  7  and to the inlet  9 , although fluid does not flow into the inlet  9  when the boiler is in use. 
         [0044]    In use of the heating system according to the present invention, the secondary source provides a heating system, for example a pre-heating system, which operates when the primary source is not operating. Consequently, the primary source does not need to heat the water from cold, but only, for example, from an intermediate temperature provided by the secondary source, thereby saving fuel and reducing heating and/or hot water costs.