Such a valve is used in hot water loops in either a faucet water system or a central heating installation, also for floor heating.

The majority of multi-unit dwellings, offices and hotels today are provided with circuits for hot water circulation in faucet water systems in order to reduce the waiting times for hot water and an unnecessary water circulation and consumption respectively of water with low temperatures, until the hot water having the desired temperature reaches the faucets.

The majority of such circulation circuits are adjusted by means of a conventional regulating valve. A constant amount of hot water is circulated continuously. This reduces the waiting times for hot water at the most remote faucets.

Instead of allowing a certain amount of water to circulate all the time, it is possible to install a thermal control valve in each loop. An intermittent adjustment of the hot water is obtained in such an installation.

The principle is, that a desired temperature is adjusted on the thermal control valve. If the temperature of the in- let water to the valve is lower than the adjusted value, the valve will be open. However, if this temperature is higher, the valve will shut off. The water flow ceases, until the water in the loop has cooled to a level below the adjusted value. The valve then opens and hot water can circulate again.

Valves already known in this field and designed for this purpose are not designed to stand possible elevated tem- peratures without being damaged. The valve bodies can, due to this and/or for other reasons, become jammed and the thermostat bodies can cease to function. Also, tightness and then also leakage problems can occur during cooling, when the valve has been shut off in order to repair the system or the like, or, primarily due to such leakage problems, a general shut-off function is not integrated into the valve, so that it has been necessary to build an additional valve for such a shut-off into the system. Additional deficiencies and drawbacks may also occur with the valves already known in this field.

EP-A-0 767 332 A2 relates to a thermostat mixer, the main object of which is to solve the problems associated with lime deposits and which are solved by using a special cage between the house and the valve body of the mixer. This mixer has an outlet, which is open all the time the mixer is used and is in communication all the time with a hot water and/or cold water inlet, i. e. if one of the inlets is entirely open, then the other inlet is entirely

closed, or alternatively the two inlets both are partially in communication with the common outlet, depending on the position of the thermostat body of the mixer. The mixer has, as a thermal protection, an auxiliary stroke spring, which is stronger than a prestressing spring, against the forces of which the thermostat body is designed to expand. Said auxiliary stroke spring is mounted in a hollow threaded bolt, the axial position of which can be adjusted via the manual handle of the mixer but which otherwise is stationarily mounted and consequently not is actuatable by operation conditions. Such a mixer does not have any shut off-but only a redistribution-function and its thermostat body, which is protected against too high temperatures through said auxiliary stroke spring, is only designed to carry out this function, but not to carry out any shut off-function and to secure this in a special operation position, e. g. during cooling.

The object of the present invention is to counteract and as far as possible remove the above-mentioned draw- backs and deficiencies and to further develop the state of the art in order to obtain a reliable multiple function- valve at relatively low costs. The life of the valve is to be large and it must be possible to install the valve in a simple and quick way and to, whenever required, use it manually. However, it is particularly important, that the automatic function of the valve is guaranteed to a high degree, also when extraordinary stresses and operation conditions exist.

These objects are attained according to the present invention by designing a valve of the type described above in the way set forth in the characterizing clause of claim 1.

Additional characterizing features and advantages of the invention are set forth in the following description, reference being made to the enclosed drawings, which show, in a partly simplified, schematical form, a preferred but not limiting embodiment. The drawings show in detail: Fig. 1 a principal outline, which depicts the installation of valves according to the invention; Fig. 2 a diametrical axial sectional view of a thermal control valve according to the invention in an open position, which also is the upper/outer end position of the valve handle ; Fig. 3 a corresponding view of the same valve in a normal operation position, closed by the thermostat body; Fig. 4 a corresponding view of the same valve in a closed position, caused by a too high temperature; Fig. 5 a corresponding view of the same valve in a manually closed position at a relatively high temperature; Figs. 6 a view corresponding to Fig. 5, when the temperature has decreased to a relatively low level; and Fig. 7 a perspective view of a valve according to Figs. 2-6.

In Fig. 1 in the drawings a typical application embodiment of thermal control valves according to the present in- vention is shown. Such valves 1 are connected to return branches 2 to a return pipe 3, which via a hot water cir- culation pump 4 leads to a water heater 5, from which a feeding pipe 6 with branches 7 leads to tapping points 8, adjacent to which branches 7 change to said return branches 2, each one being provided with its valve 1.

The valves are closed and opened independently owing to the adjusted temperature. Thus, a hot water circulation through said branches solely occurs, provided the temperature falls below an adjusted value. In this way an unnecessary water circulation is avoided.

Valve 1, shown in Figs. 2-6, comprises a house 9 having an inlet 10 and an outlet 11, which are separated by a partition wall 12 with a seat 13, arranged in the wall and interacting with and counteracting the actions of a regu- lating spring 14 having a valve body 15, which is guided in a valve housing wall 16 and influenced by a thermo- stat body 17, which in its turn is influenced by a spindle 18, the axial position of which and consequently the po- sition of the valve body and the contact pressure of the valve body against the seat respectively being adjustable by means of a valve handle 19. Since the static pressure in water heater installations having tapping points may fluctuate between 2 and 10 bars, the diameter of the spindle is minimized in order to stand high static pressures.

Valve body 15 is designed as a housing 20 with a closed bottom 21, exposed to seat 13, the periphery of the bottom suitably being designed as a frustrum of a cone, the cone angle of which preferably is smaller than the cone angle of the seat, the cone portion of the seat with the smallest diameter cutting into the middle of the bottom cone in order to obtain a linear sealing, in which way certain substantial tolerances never can detrimentally affect the sealing function and, when the valve initially is used as well as after e. g. a wear during many years, a satisfactory sealing is guaranteed.

From the end of housing 20, which is positioned behind in relation to seat 13, a ring flange 22 projects radially outwards, to which a guide bushing 23 is peripherally connected, which axially projects above the ring flange in both directions, that portion of the guide bushing, which faces the seat, preferably jointly with an inclined alignment surface 24 all around on the outside of housing 20, forming an alignment channel 24'and a holding- on element for regulating spring 14, the opposite end of which being supported by that side of partition wall 12, which is exposed to the outlet, around seat 13, preferably outside a ring bead 25, which projects from the partition wall, as a positioning indication element.

That axial portion of the guide bushing, which is turned away from the seat, functions as an alignment and pro- tection element for thermostat body 17, which jointly with a portion, which fills housing 20 with an approximate fit, is provided with a flange-like collar 26, in connection with which the thermostat body is provided with telescope-or cascade-like elements 27,28,29, with decreasing diameter, of which the outermost element, having the smallest diameter, functions as a piston, being designed to adjustably bear on spindle 18.

Said adjustability is obtained by means of a calibration device 30, which from the side of the thermostat body by means of a bolt portion 31, provided with an outer thread, is inserted into a through bore 32, provided with a corresponding inner thread, in spindle 18. That end of bolt portion 31, which is turned away from the thermostat

body, is provided with adjustment means 33, e. g. a socket head cap screw hole, which can be reached through the bore in the spindle and through valve handle 19 after a removal of a cover 34, which with a press fit is inserted into a through opening 35 in bottom 36 of the valve handle.

In said opening 35 in the bottom of the valve handle an inner flange 37, made of the bottom of the handle all around, inwardly projects on the side, which is turned towards set-off 16, which inner flange 37 leaves an ope- ning 38, through which spindle 18 is inserted with a slip fit. The end of the spindle adjacent the cover is provided with a lock ring 40, inserted into a groove 39 all around, a sliding plate 41 being provided between lock ring 40 and flange 37. Also on that side of flange 37, which is turned towards the thermostat body, the spindle is surrounded by a sliding plate 42 having an axial collar 43, designed to bear on the spindle on that side, which is turned towards the thermostat body. Collar 43 functions as a positioning and centering element for the one end of a screw-shaped overload spring 44, which concentrically surrounds the spindle and by its opposite end is supported by a corresponding sliding plate 45 having a collar 46, which two elements roughly at the same height as piston 29 surround the spindle and are pressed by spring 44 against a spindle set-off 47 all around via a spacer 48. The compressive force of the overload spring is 1.5-10, preferably 4, times larger than the compressive force of the regulating spring.

Thus, in connection with said set-off 47 spindle 18 extends with a somewhat increased diameter to its free end, which is turned towards the valve body and provided with a projecting stop flange 49 all around, which is designed to limit the movement of the spindle in a direction away from the valve body by, in such an outer posi- tion according to Fig. 5, bearing on a stop element, preferably a first inner flange 50 of an essentially casing- shaped 0-ring holder 51, which with a form fit from the outside is inserted into wall 16 having an inner wall set- off 52 as an insertion limitation and a lock ring 53, inserted into the wall opening all around, as a lock element.

Adjacent wall set-off 52 holder 51 is provided with an outer groove 54 all around, designed to receive an 0-ring 55, whereas between inner flange 50 and a second inner flange 56, at an axial distance in a direction towards the handle, a groove 57 is formed, designed to receive an O-ring 58.

Calibration device 30 has, in connection with bolt portion 31, a saucer-shaped base portion 59, which is guided in an expanded spindle opening 60, which is concentric in relation to bore 32, the base portion being surrounded by a groove 61 all around with an O-ring 62 mounted therein. Free end side 63 of base portion 59 suitably is concave or conically recessed in order to guide piston 29 in an optimal way.

In the bottom of the handle a lock screw 64 with a socket head cap screw hole 65 is axially and excentrically inserted from the outside. The bottom of the lock is on its outer side provided with a temperature scale 66 and possibly additional symbols. The scale suitably has adjustment lines between 35 and 65° C. Handle casing 67 is,

by means of an inner thread, screwed onto an outer thread on wall 16 and can be provided with a mounting lug 68 for a marking plate (not shown).

Valve house 9 is, within the areas of inlet 10, provided with a hollow raised portion 69, designed to receive a thermometer 70, which can be fastened by means of a stop screw 71, inserted through the raised portion. The thermometer shows, due to its exposure against the hollow space of the raised portion and the material of the house, the temperature of the medium, which flows through the valve. A wall 72 between raised portion 69 and wall 16 can be used as a visual reference.

The calibration can be carried out by turning handle 19 to its upper/outer end position (Fig. 2). This position can easily be detected, when stop flange 49 of spindle 18 bears on first inner flange 50 and simultaneously inner flange 37 of the handle bottom bears on lock ring 40 via sliding plate 41. This position is also the maximal open position of the valve. Cover 34 with its temperature scale 66 is loosely mounted in opening 35, e. g. the 65° C line being directed towards wall 72. The handle then is turned clockwise, until the valve is positioned at 35°. The cover is removed and calibration device 30 is turned, until a flow of X 1/h is obtained. The 35°-line on the scale is directed towards wall 72 and the cover is completely pressed into opening 35, a snap-in of the cover being obtained due to the design of the cover and said opening, shown in the drawings.

The temperature adjustment can be done by adjusting the valve at e. g. 55° C, after which lock screw 64 is tightened.

The shut-off function/tightness is controlled by turning the handle clockwise to a stop, which it is easy to feel, when handle bottom 36 bears on the free end of wall 16 and simultaneously overload spring 44 via the spindle, the calibration device and thermostat body 17 exerts a shut-off pressure on valve body 15, which always is suffi- ciently large. By means of a flow meter (not shown), connected to the outlet, it can be shown, that the flow is zero.

The handle of a valve, preadjusted in this manner, can be turned, the distance between the valve body and the seat being changed. This distance will determine, at which temperature the valve is to be opened/shut-off, due to a precise length of the thermostat body for a certain temperature. The linear movement, which a turning of the handle causes, is transferred via the overload spring, which is stiff compared to the regulating spring.

In case the temperature of the water is lower than the value, which is adjusted by means of the scale, the valve body will not tightly bear on the seat but form an opening gap, through which water cannot pass. In case the temperature of the water in branch 7 increases to a higher temperature than the adjusted temperature, the valve body will be completely pressed against the seat, since the expansion of the thermostat body primarily is seized

by regulating spring 14, which is weaker than over load spring 44. Thus, a sufficiently large surface pressure will be exerted between the valve body and the seat, which results in, that the flow ceases and the valve is shut off.

If the temperature for any reason continues to increase in the pipe line system, the length of the thermostat body will increase additionally. To absorb this length and stress increase and prevent, that valve parts are subjected to over loads, which can damage and destroy them, the valve is provided with an over load spring 44, which under said operation conditions is compressed by the thermostat body during a certain limited movement of spindle 18.

When a water and sanitation system is to be repaired etc., it ought to be possible to shut off the loop. Thus, the valve according to the present invention is provided with a manual shut-off function. In order to shut off the valve the handle is turned clockwise to said stop position. The overload spring will then be compressed additionally, e. g. with 5 mm. This extra energy buffer is used to compensate for the length reduction of the thermostat body, which is caused by the cooling, when the valve has been shut off at an elevated temperature.

The overload spring will in this situation guarantee, that a sufficiently high surface pressure is maintained between the valve body and the seat, the valve remaining tight also after the cooling.

The present invention is not limited to the embodiments described above and shown in the drawings but can be modified and supplemented in an arbitrary manner within the scope of the inventive idea and the following claims.