Mixing valve

A mixing valve for sanitary operations comprises a valve seat disk having two inlet passage openings and a controlling disk held against the valve seat disk adjustable by a handle, so that the relative proportions of the fluids mixed are controllable by rotation of the controlling disk and the flow rate of the mixed fluid is controlled by a displacement of the controlling disk, wherein the two inlet passage openings for the fluids mixed are formed symmetrically positioned in one half of the valve seat disk, each of the two inlet passage openings being formed as an arcuate segment positioned on a circular arc, and wherein a transfer passage formed in the controlling disk is brought into overlap with the inlet passage openings adjacent an arc shaped front edge of the transfer passage. To improve the control of the proportions of the fluids mixed the inner sides of each of the inlet passage openings have a constriction extending a distance of substantially one-third of the length of the arcuate segment corresponding to each of the inlet passage openings, and the constriction is positioned a distance of substantially 0.4 of the length of the arcuate segment from the front side of the inlet passage openings adjacent the symmetry axis of the valve seat disk.

FIELD OF THE INVENTION 
My present invention relates to mixing valves for blending and mixing the 
flows of two miscible fluids, and, more particulary, to mixing valves for 
mixing a cold water flow and a warm water flow for sanitary fixtures. 
BACKGROUND OF THE INVENTION 
Mixing valves used for mixing two fluids for sanitary fixtures, 
particularly warm and cold water, can comprise a valve seat disk having 
two inlet passage openings and a controlling disk held against the valve 
seat disk and adjustable by a handle, so that the relative proportions of 
the fluids mixed are controllable by rotation of the controlling disk, and 
the total flow rate of the mixed fluid is controlled by a somewhat linear 
displacement of the controlling disk. 
The two inlet passage openings for the fluids to be mixed are formed 
symmetrically in one half of the valve seat disk. Each of the two passage 
openings is formed as an arcuate segment on a circular arc. Transfer 
passage formed in the controlling disk is brought into overlapping 
relationship with the inlet passage openings adjacent an arc shaped front 
edge of the transfer passage. 
In mixing valves used to control the water temperature in a sanitary 
fixture it is essential between the extreme "cold" and "hot" positions to 
have a comparatively large range of swing or pivot angle for the "comfort" 
temperature range of between 30.degree. to 45.degree. C. With these valves 
the temperature range can easily be brought close to the body temperature 
of the user and comparatively exactly controlled, but even slight 
deviations of from 1.degree. C. to 2.degree. C. from the desired 
temperature are noticeable. 
In the known mixing valves, the adjustment of the relative proportion of 
the mixed fluids, e.g. cold and warm water, is substantially proportional 
to the rotational angle of the handle , so that in a total pivot angle or 
swing of say 110.degree. only a pivot angle of about 20.degree. is 
available for a mixed water temperature range of from 30.degree. to 
45.degree. C. and thus sensitive fine adjustment is made only with 
difficulty. 
German Patent DE-OS No. 32 44 121 describes a mixing valve in which a more 
sensitive fine adjustment of the relative proportions of the fluids mixed 
is attained in the preferred temperature range. In this mixing valve 
structure the rotation axis of the controlling disk is arranged eccentric 
to the valve seat disk axis. Therefore, among other requirements the valve 
housing must be constructed with supporting receptacles eccentric to each 
other for the valve seat disk and the controlling disk. 
OBJECTS OF THE INVENTION 
It is an object of my invention to provide an improved mixing valve for 
mixing two fluids whereby the drawbacks described above would be obviated. 
It is also an object of my invention to provide a simpler and more easily 
constructed sanitary fixture with which a finer adjustment of the relative 
proportions of the fluids mixed in the outflow is possible. 
It is also an object of my invention to provide a mixing valve for mixing 
warm and cold water in a sanitary fixture, wherein the relative adjustment 
angle range in the comfort zone is a maximum and substantially greater 
than 20.degree., but the mixing valve does not have unusual or 
difficult-to-construct structures like eccentrically positioned valve seat 
disks or controlling disks. 
Another object of my invention is to provide especially precise fine 
adjustment of water temperature in the range of 30.degree. to 45.degree. 
C. 
SUMMARY OF THE INVENTION 
These objects and others, which will become more readily apparent 
hereinafter, are attained in accordance with my invention in a mixing 
valve for operation in sanitary conditions comprising a valve seat disk 
having two inlet passage openings and a controlling disk held against the 
valve seat disk adjustable by hand, so that the relative proportions of 
the fluids mixed are controllable by rotation of the controlling disk. The 
total flow rate of the mixed fluid is controllable by a generally linear 
displacement of the controlling disk two inlet passage openings for the 
fluids to be mixed being formed symmetrically in one half of the valve 
seat. Each of the two inlet passage openings is formed as an arcuate 
segment positioned on a circular arc. A transfer passage formed in the 
controlling disk is brought into overlapping relation with the inlet 
passage openings adjacent an arc shaped front edge of the transfer 
passage. 
According to our invention the inner sides of each of the inlet passage 
openings have a constriction extending a distance of substantially one 
third the length of the arcuate segment corresponding to each of the inlet 
passage openings, and each constriction is spaced a distance of 
substantially 0.4 of the length of the arcuate segment corresponding to 
each of the inlet passage openings from a front side of each of the inlet 
passage openings proximate to the symmetry axis of the valve seat disk. 
According to a further feature of our invention the valve seat disk is 
substantially circular and the centers of curvature of both of the inlet 
passage openings are identical and offset a distance from the center of 
the valve seat disk on the other opposing half of the controlling disk in 
a direction parallel to the symmetry axis. 
Advantageously according to my invention each of the inlet passage openings 
at the front side adjacent the symmetry axis has a maximum width and is 
constricted in the direction of the other opposing side of the inlet 
passage openings, wherein the other opposing sides of both of the inlet 
passage openings have a width, which is substantially 0.75 of the maximum 
width and the width of the constriction of a suitably narrowed shape is 
subtantially 0.5 to 0.3 of the maximum width. 
Also according to a further desirable feature the center of curvature of 
both of the inlet passage openings is displaced substantially 1 mm from 
the center of the valve seat disk, and the radius of the arcuate segment 
of the inlet passage openings is substantially 13 mm, wherein both of the 
front sides of the inlet passage openings form a semicircle on the outer 
edges thereof, and each of the arcuate segments corresponding to each of 
the generally kidney-shaped inlet passage openings extend from 5.degree. 
to 75.degree. of arc as measured from the symmetry axis, and the maximum 
width is about 3.6 mm. 
Furthermore, the valve seat disk advantageously has an outlet passage 
opening for the rearward flow of mixed fluid, and a controlling disk, in 
which a transfer passage is formed as a surface passage for connecting 
selectively the inlet passage openings and the output passage opening. The 
transfer passage has a trapezoidally shaped longitudinal cross section, 
which is narrowed in the direction of the outlet passage opening. 
Other advantageous features of our invention include the following: the 
maximum breadth of the transfer passage is substantially 15 mm, and the 
arc shaped front edge of the transfer passage has a radius of 
substantially 10 mm, whose corners are rounded with a radius of 
substantially 2.5 mm, and the maximum distance to the pivot axis of the 
controlling disk is substantially 9.5 mm, wherein the side walls of the 
transfer passage are connected to the front edge with an inclination of 
substantially 7.5.degree. to the center axis. 
With the above features according to my invention the temperature of the 
mixed fluid flow output in the range from 30.degree. to 45.degree. C., the 
so-called comfort zone, can be more accurately and conveniently adjusted, 
since the range of the adjustment swing angle corresponding to this 
temperature range can be raised to 34.degree. of the total range of 
110.degree. of angle.

SPECIFIC DESCRIPTION 
The mixing valve of the invention is mounted in a cylindrical valve housing 
1 attached to a structural unit, which can be completely mounted in a 
sanitary fixture or the like. In the bottom of the valve housing 1 a valve 
seat disk 2 of ceramic material is supported fixed in position and has an 
inlet passage opening 21 for cold water and an inlet passage opening 22 
for warm water as well as an outlet passage opening 23 for mixed water, 
which are connectable to suitable conduction passages in the sanitary 
fixture, which are not shown in the drawing. 
A controlling disk 3 with a transfer passage 31 made from ceramic material 
is mounted on the valve seat disk 2. Both disks 2 and 3 bear with 
microfinished surfaces on each other , so that a water tight seal is 
guaranteed. 
The top side of a controlling disk 3 opposite the side of the controlling 
disk 3 contacting the valve seat disk 2 is mounted and sealed according to 
the shape of these parts with a cover and guide cap 32, thus forming a top 
on the transfer passage 31, which acts as a smooth passage wall or forms a 
mixing chamber. 
The cover and guide cap 32 is engaged on the other side by a rotating 
member 4 mounted rotatably in the valve housing 1, wherein a twin armed 
lever 42 is mounted in this rotating body 4 on its first rotation axis 41, 
which besides the usual rotational motion can be inclined or pivoted about 
a second rotation or tilt axis 43 lying perpendicular to the first 
rotation axis 41. 
The twin armed or double-arm lever 42 is additionally connected with its 
inside lever arm with the cover and guide cap 32 in the vicinity of the 
pivot joint axis 38. The lever 42 can experience, for example, by a handle 
101, an inclination or tilting, so that cover and guide cap 32 with the 
controlling disk 3 is pushed radially to the valve seat disk 2, whereby 
the fluid flow rate metering occurs. By a rotation of the lever 42 and 
rotational body 4 the cover the guide cap 32 together with the control 
disk 3 is movede suitably toward the valve seat disk 2, whereby the 
proportions of wram and cold water in the mixture are controlled. 
The valve seat disk 2, is, as can be seen especially from FIG. 2, 
substantially circular, the inlet passage openings 21 and 22 being mounted 
symmetrically on one half of the valve seat disk 2, while on the other 
opposing half outlet passage opening 23 for the rearward flow of mixed 
water is positioned. The inlet passage openings 21 and 22 are formed on a 
circular arc with a radius 20 of about 13 mm, wherein the center point of 
the circular arc is displaced a distance of about 1 mm on the other 
opposite half of the valve seat 2. 
Both inlet passage openings 21 and 22 extend from the symmetry axis 25 from 
5.degree. to 75.degree. of arc. The inlet passage openings 21 and 22 
positioned on the circular arc with radius 20 have a maximum width 229 of 
2.6 mm on the front side 29 adjacent the symmetry axis 25, and are 
narrowed on the side lying opposite this front side 29, wherein the width 
228 of this opposite side amounts to about 0.75 of the maximum width. 
On the inside of the inlet passage opening 21 or 22 a constriction 24 of 
about one third of the length of the arc segment corresponding to an inlet 
passage opening 21 or 22 is formed, wherein the constriction 24 begins at 
a distance 27 of approximately 0.4 of the length of the arcuate segment of 
the inlet passage opening 21 or 22 from the side adjacent the symmetry 
axis 25. The sides of the passage openings 21 and 22 are formed 
semicircular on their outflow sides. 
The controlling disk 3 is, as shown in FIG. 3, provided with a transfer 
passage 31 forming a smooth opening or port symmetric to the center axis 
37. In the vicinity of the inlet passage opening 21 and 22 the transfer 
passage 31 is bounded by an arc shaped front edge 34, which has a maximum 
distance 39 from the pivot axis 38 of about 9.5 mm, wherein the radius 335 
of the arc shaped front edge 34 is about 10 mm. The maximum breadth 33 of 
the front edge 34 is about 15 mm, and the corners 35 of the front edge 34 
are rounded with a radius 336 of about 2.5 mm. The side walls 36 linearly 
connect to both corners 35 of the front edge 34 and have an inclination of 
about 7.5.degree. to the center axis 37. In the vicinity of the outlet 
passage opening 23 for the rear flow of the mixed water the transfer 
passage 31 is so formed that in each valve position an adequate cross 
section for the rearward flow of mixed fluid is guaranteed. 
In FIGS. 4 and 5 top views of both the valve seat disk 2 and the 
controlling disk 3 are given showing how the inlet passage openings 21 and 
22 coincide with the transfer passage 31 in two different adjustment 
swings of the disks 2 and 3. The adjustment swing angle controls the 
adjustment swing of the disks 2 and 3 and thus the proportion of warm and 
cold water admitted to the mixed overflow. An accurate and complete study 
of the relationships of outflow temperature and flow rate versus 
adjustment swing angle is summarized in FIGS. 6 and 7. 
In FIG. 6, the above-described mixing valve having a zero displacement or, 
that is, a mixing valve, in which the inlet passage openings 21 and 22 are 
displaced an amount equal to zero, in its mixing configuration is 
described. 
The values reported in the graphs of FIG. 6 were measured in a trial with 
3.3 bar pressure cold and warm water, with the water freely flowing and 
with an initial temperature of 15.degree. C. for the cold water and 
70.degree. C. for the warm water. The pivot or adjustment swing angle in 
degrees is illustrated on the abscissa, while on the right ordinate the 
temperature of the mixed water in Celsius degrees and on the left ordinate 
the water flow in liters per minute are illustrated. 
Curve 5 shows the dependence of the temperature of the mixed water on the 
adjustment swing angle, while curves 6 and 7 show the flow rate of the 
flowing cold and warm water. 
As is apparent, the pivot angle change for a temperature change of the 
mixed water from 30.degree. to 45.degree. C. amounts to 28.degree.. 
Similarly in FIG. 7 the mixing behavior of the previously described valve 
as shown, wherein the inlet passage openings 21 and 22 are displaced about 
a distance 28 of a millimeter. With the same trial conditions, as were 
used for the case of FIG. 6, with a central displacement and lever 42 is 
pivoted about 34.degree. for a change of temperature from 30.degree. to 
45.degree. C., as is apparent from the graph. The so-called comfort zone 
comprises, therefore, about a 34.degree. range, wherein the maximum pivot 
angle of the mixing valve amounts to 110.degree.. 
My invention is not to be considered limited to the described example, but 
also can be realized in a mixing valve, in which a mixed water rear flow 
is not provided through the valve seat disk. For example, the transfer 
passage 31 can be radially extended from the controlling disk or coaxially 
through the controlling disk. In the latter embodiment the transfer 
passage 31 can be limited to an approximately sickle shaped passage 
opening with circular front edges.