Mixing valve

A mixer valve includes a rotational assembly for selecting a temperature of the water up to a maximum temperature. The rotational assembly includes a selectable “comfort” temperature indicator, that can be set independently of the maximum temperature, and does not affect the maximum temperature. The valve also includes check valves for preventing cross flow between the hot and cold pipes. A check valve insert is provided which includes a shutoff for the water flow when removing the check valve for service. The shutoff and removal of the check valve can be effected with a single tool.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates to mixing valves. More particularly it relates to thermostatic mixing valves with improved access to check valves and filter screens and improved settings for comfort temperatures.

Thermostatic mixing valves can provide a source of water having a desired temperature and can maintain the desired water temperature substantially constant once set. Such devices are well known in the art. See e.g. U.S. Pat. No. 6,279,604 and U.S. patent application publication 2004/0000594. Typically, the desired water temperature is obtained by controlling the relative proportions of hot and cold water admitted to a mixing chamber and adjusting the relative proportions to maintain the desired water temperature substantially constant.

To prevent the temperature from being set at a temperature that risks scalding, a temperature stop is typically provided on the mixing valve. The valves often also include a method for setting a lower “comfort” level.

To prevent cross flow between the hot and cold input lines, check valves can be provided between the hot and cold water supplies and the mixer valves. Also, screens can be provided to avoid debris from clogging the valve interior.

While thermostatic mixing valves are known in the art, these known devices suffer from a number of disadvantages. For example, in some prior art devices, when the comfort level is selected, the maximum temperature selection is determined by a fixed increment therefrom. In any event, to properly maintain the valve, the check valves and associated screens need to be periodically cleaned. This process can require the use of a number of tools, requires some skill, and can be time consuming.

Therefore, there remains a need for an improved thermostatic mixer valve in which the check valves and screens are easily and quickly cleaned. Furthermore, there remains a need for an improved thermostatic mixer valve that mechanically provides a user selectable comfort level independent of the maximum temperature level.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a mixing valve comprising a valve body having a check valve receptacle coupled to an inlet water passage and also an outlet water passage, and a check valve insert sized and dimensioned to be received in the check valve receptacle. The check valve insert has a stop body with a shutoff element and a check valve sized and dimensioned to be received in the stop body, wherein the stop body is selectively movable in the receptacle to position the shutoff element to decouple the inlet water passage from the outlet water passage. When so positioned, the check valve is selectively removable from the stop body for service.

In preferred forms, the stop body and check valve each include a receptacle sized and dimensioned to receive a single tool, such that the water flow can be deactivated and the check valve removed with the selected tool.

In another aspect of the invention, an assembly for setting an output temperature for a thermostatic mixer valve is provided. The assembly includes a thermostatic mixing cartridge having an undercap, an overcap including a first detent member, and a rotational stem adaptor coupled between the undercap and the overcap and having a second detent member. The first detent member and the second detent member interact to provide a comfort temperature setting.

In a preferred form of the invention, the undercap includes a maximum stop temperature tab. The rotational stem adaptor includes a tab for mating with the maximum stop tab to limit the output temperature to the selected maximum.

In another preferred form, the undercap can include a first plurality of teeth, and the overcap can include a second plurality of teeth that mate with the first plurality of teeth.

In another preferred form, the first detent member can be a ramp. The second detent member can be a flexible tab.

Thus, the present invention provides improved methods and apparatuses for maintaining or servicing check valves in a mixing valve, as well as improved means for selecting a comfort level temperature when the valve is a thermostatic mixing valve.

These and still other advantages of the present invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there are shown preferred embodiments of the invention. Such embodiments do not represent the full scope of the invention, and reference is made therefore, to the claims herein for interpreting the full scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures, a thermostatic mixer valve10includes a valve body12having cold and hot water inlets14and16respectively, and upper and lower water outlets18and20respectively. Check valve inserts22and24providing check valves (and filter screens) for each of the hot and cold water inlets16and14are received in check valve receptacles (service stop receptacles)49provided in the valve body12. The valve body12further includes a cartridge chamber26for receiving a thermostatic cartridge assembly27, including both a thermostatic mixer cartridge36, and a temperature setting assembly74adapted to receive a knob or other actuator for selecting a temperature level.

The cartridge36includes cold and hot water inlets28and30and associated sealing gaskets32and34which are received in the valve body12, and adjusts the temperature of the water supplied to the outlets18and20based on a position selected by the temperature setting assembly74in a manner known in the art. While a number of thermostatic mixer valve cartridges could be used in the present invention, one such cartridge is disclosed in U.S. patent application publication 2004/0000594, which is hereby incorporated herein by reference for its description of such devices. When using the described cartridge, the cartridge can be rotated one hundred and eighty degrees to reposition the hot and cold inlets, thereby allowing a user to account for errors in plumbing the pipes and various other situations in which the hot and cold inputs have been reversed.

Referring now toFIGS. 2 and 3, the check valve insert24is inserted in a check valve receptacle49. The check valve receptacle49is sized and dimensioned to receive the check valve insert24, and includes an upper portion53that is threaded on the inside surface. Access ports are provided from the receptacle49to a water out passage64and a water in passage66, such that water flows from the inlets14and16into the water passage66to the check valves60, and out the water passage64to the cartridge36in normal operation.

Referring still toFIG. 3, the check valve insert24includes a service stop body56and a check valve60, which is received in the service stop body56. The service stop body56includes an upper portion with a radially-extending lip68that is threaded to mate with the upper portion53of the check valve insert24, and a shutoff disc70at the opposing end in the receptacle49. The lip68is positioned a distance from the top of the body56selected to locate the shutoff disc70to decouple the water inlet passage66from the water outlet passage64when servicing the check valve60as described below. To assure appropriate sealing, the shutoff disc70includes a rubber o-ring71. An inner surface73of the upper portion of the body56is also threaded to receive the check valve body58.

Referring still toFIG. 3, the check valve60is received into a check valve body58having a threaded upper portion61that mates with the threaded inner surface73of the upper portion of the service body56, and a filter screen62. A receptacle54is substantially centered in the check valve body58and is sized and dimensioned to receive a driving tool such as a ⅜″ socket driver for threading the check valve body58into and out of the service body56.

Referring still toFIG. 3, and again also toFIG. 2, the service stop body56includes a hinged drive lid48that is coupled to the top of the service stop body56by a hinge51. The drive lid48includes a receptacle50, substantially centered in the drive lid48, and also sized and dimensioned to receive the driving tool described above. A bracket52coupled to the valve body12extends over the edge of the check valve receptacle49, and is positioned to interact with the radially-extending lip68from the service stop body56to limit motion of the service body56from the receptacle49for service. Referring now toFIG. 4, when the lid48is pivoted along hinge51, the receptacle54in the check valve60can be accessed, and the tool inserted to remove the check valve body58and check valve60.

To access the check valve60for service, the driving tool is inserted into the receptacle50in the drive lid48and the service stop body56is threaded counter-clockwise (upward) along the upper portion53of the check valve insert receptacle49until the lip68reaches the bracket52, moving the check valve insert24from the position shown inFIGS. 2 and 3to that shown inFIGS. 4 and 5. When the bracket52is reached, the shutoff disk70and associated rubber o-ring71are positioned in the check valve receptacle49to decouple the water input passage66from the water output passage64, thereby preventing water flow into the receptacle49and effectively shutting off the valve10, as shown inFIGS. 4 and 5.

When the valve is shut off, the check valve60and associated filter screen62can be removed as shown inFIG. 6by inserting the same driving tool that was used to move the service stop body56into the receptacle54in the check valve60. By providing the same receptacle in each of the service stop body56and check valve body58, only one tool is required to remove the check valve body58. After service is complete, the driving tool is again used to re-insert the check valve body58into the service stop body56, and to drive the service stop body56back into the receptacle49, and therefore to the position shown inFIG. 3.

Referring now toFIG. 7, the thermostatic cartridge36includes a drive spindle37and undercap29to which the temperature setting assembly74is connected. The temperature setting assembly74includes a rotational stem adaptor38, overcap40, a wave compression spring42and a retaining nut44. The undercap29of the thermostatic cartridge36further includes a plurality of teeth31extending radially around the circumference of the cartridge36, and which mate with teeth41in the overcap40. A pair of rotational stop tabs33and35are provided on the undercap29coupled to the thermostatic mixer cartridge36to provide a minimum and a maximum temperature position for the temperature setting assembly74, and therefore to limit the rotation of the assembly and the temperature of water obtained from the valve10.

The stem adaptor38is received between the detent cap40and the thermostatic cartridge36and is maintained in position by a fastener46received in an aperture47in a distal end of the spline adaptor38. The retaining ring44is received over the overcap40, and is threaded into the cartridge chamber26. The wave compression spring42is positioned between the overcap40and the retaining ring44, and provides a force on the overcap40to maintain the overcap40against the drive spindle37of the thermostatic cartridge36, and to maintain the teeth31mated with the teeth41.

Referring still toFIG. 7and also toFIG. 8, the stem adaptor38includes a rotational stop tab39that mates with the minimum and maximum temperature tabs33and35in the cartridge36to provide a rotational stop of minimum and maximum temperature, and a detent member in the form of a comfort temperature tab43. The comfort tab43extends radially from the outer circumference of the adaptor38, and is substantially centered adjacent an elongate aperture76inset from the outer edge of the spline adaptor38. The aperture76allows the tab43to “flex” inward and outward, as described below.

Referring still toFIG. 8, the overcap40is substantially cylindrical in shape, including a plurality of teeth41extending radially outward and sized and dimensioned to mate with the teeth31on the cartridge36at a variety of possible positions. A mating detent member, here a ramp72, is also provided extending from an inner surface of the detent overcap40, and positioned a distance above the teeth41. When assembled, the ramp72interacts with the comfort temperature tab43on the rotational stem adaptor38to provide an indication to the user when the comfort position is key reached, also as described below. This is in the form of resistance to turning. However, further turning past this point is still possible.

Referring now toFIGS. 9-11, a cutaway view of the temperature setting assembly74taken along the line9-9inFIG. 1is shown as the assembly74is moved to varying positions. Referring first toFIG. 9, here the tab39on the rotational stem adaptor38is shown in contact with the maximum temperature tab35on the cartridge36, indicating that the maximum temperature has been reached. Although a number of different temperatures can be selected, a maximum anti-scald temperature of 120 degree Fahrenheit is typical.

Referring now toFIG. 10, here the temperature setting assembly74is shown rotated to a new position, and the comfort tab43is shown approaching the ramp72in the cap40. The comfort tab43follows the ramp72to a high point78at which the user will feel the tab43fall off of the ramp72indicating that the selected comfort temperature has been reached. As the tab43is moved along the ramp72, the aperture76formed in the adaptor38following the outer surface of the adaptor38allows the bottom surface of the rotational stem adaptor38to flex inward. Therefore, the tab43can move radially inward as it follows the ramp72and flex back out as it passes the high point78. The comfort tab43does not provide an actual “stop”, but can be moved past the comfort position if desired. Rotation would then be allowed to continue until the tabs35and39meet, as discussed above.

Referring now toFIG. 11, the relative position of the components in the temperature setting assembly74are shown as an adjustment to the selected comfort temperature is made. To adjust the selected temperature, a user pulls on the overcap40axially to remove the teeth41in the overcap40from the teeth31in the undercap29of the cartridge36. When the teeth are disengaged, the overcap40can be rotated to a new position, to reposition the ramp72relative to the stops33and35. When the ramp72is in the position selected by the user, the overcap40is released so that the teeth31re-engage with the teeth41. The point78is therefore repositioned, providing an adjustment in the selected comfort temperature, while the stop tabs35and39remain in the same orientation, thereby maintaining the selected maximum temperature irrespective of the selected comfort temperature. The wave compression spring42maintains a force on the detent overcap40to assure that the teeth31and41are engaged.

The invention therefore provides a number of advantages. The check valve inserts provide check valves concentric with a shut-off device, which helps to reduce the overall size of the valve. The check valves, moreover, can be serviced with a single tool, thereby simplifying maintenance of the valve. Furthermore, servicing can be done by even those with minimal plumbing skill. Further, a comfort temperature selection is provided which allows the user to select a comfort level setting without affecting the maximum temperature.

It will be appreciated that a variety of changes can be made to this structure without departing from the spirit or scope of the invention. For example, although a specific driving tool is described above, various other tools could also be used. Additionally, although the valve is shown and described as providing only a temperature mixing function, volume controls can also be integrated with the valve, particularly in the inlet and outlet ports. Still other modifications could be made within the scope and spirit of the invention.

INDUSTRIAL APPLICABILITY

Disclosed are mixer valves useful in shower and other bathing installations.