AU2017200743A1

AU2017200743A1 - Thermostatic mixer with thermal bypass

Info

Publication number: AU2017200743A1
Application number: AU2017200743A
Authority: AU
Inventors: Marco Caleffi
Original assignee: Caleffi SpA
Current assignee: Caleffi SpA
Priority date: 2016-02-05
Filing date: 2017-02-03
Publication date: 2017-08-24
Anticipated expiration: 2037-02-03
Also published as: ITUB20160073A1; AU2017200743B2

Abstract

THERMOSTATIC MIXER WITH THERMAL BYPASS A thermostatic mixer (10) with thermal bypass comprising a valve body (11) in which are obtained a cold water inlet (12), a hot water inlet (13), a mixing chamber (14), and an outlet (15) of mixed water connected to the mixing chamber (14), wherein inside the valve body (11) a thermosensitive actuating device (16) is installed which expands or reduces according to the temperature and to which a shutter (17) is fixed that moves axially on the action of the device (16) to adjust the flow of hot and cold water into the mixing chamber (14) so as to have at the outlet (15) a water mixed at a presettable determined temperature, wherein the mixer (10) comprises a piston (24) against which the device (16) abuts, first elastic means (25) acting on the device (16) in the direction of the piston (24) and second elastic means (26) acting on the piston (24) in direction of the device (16), wherein the piston (24) has an end protruding outside the valve body (11) and provided with external gripping means (27) for grasping and moving the piston away from the device (16), causing the movement of the shutter (17) on the action of the first elastic means (25) in a position of stopping or reducing the flow of cold water to perform the function of thermal bypass. Fi g. 4 B25 A L\ Filg. 5 18 Fig. 6

Description

ι 2017200743 03 Feb 2017

THERMOSTATIC MIXER WITH THERMAL BYPASS

BACKGROUND OF THE INVENTION

[0001] Thermostatic mixers are used in plants producing hot water for sanitary use.

[0002] The function of such mixers is to maintain constant at a preset value the temperature of the mixed water regardless of the variations in temperature or in incoming pressure or in the taken flowrate. A thermostatic element inside the mixer is completely immersed in the conduit of the mixed water and reduces or expands, causing a shutter to move that controls the passage of incoming hot or cold water; if there are variations in temperature or in incoming pressure, the thermostatic element reacts automatically, resetting the preset temperature value.

[0003] Some mixers feature the thermal bypass function, which is used for the thermal disinfection of the plant. This enables water to be sent to the installations at temperatures that are much higher than those of normal use. The very hot water, above 60°C, which circulates in the plant, in particular enables the dangerous legionella bacterium to be destroyed, the ideal environment for which is stagnant water and the presence of encrustations and sediments.

[0004] However, in mixers with this function, switching from the “thermal bypass” function to the “thermostatic mixer” function, the previously set calibration parameters are modified.

[0005] This forces the mixing parameters to be set again.

OBJECT OF THE INVENTION

[0006] It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages, or at least provide a useful alternative.

SUMMARY OF THE INVENTION

[0007] Accordingly, the present invention provides a thermostatic mixer with thermal bypass comprising a valve body in which are obtained a cold water inlet, a hot water inlet, a mixing chamber, and an outlet of mixed water connected to the mixing chamber, wherein inside the valve body a thermosensitive actuating device is installed which expands or reduces according

AH25(12531411_1):MSL 2 2017200743 03 Feb 2017 to the temperature and to which a shutter is fixed that moves axially on the action of the device to adjust the flow of hot and cold water into the mixing chamber so as to have at the outlet a water mixed at a presettable determined temperature, wherein the mixer comprises a piston against which the device abuts, first elastic means acting on the device in the direction of the piston and second elastic means acting on the piston in direction of the device, wherein the piston has an end protruding outside the valve body and provided with external gripping means for grasping and moving the piston away from the device, causing the movement of the shutter on the action of the first elastic means in a position of stopping or reducing the flow of cold water to perform the function of thermal bypass.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to understand the invention better, a description is given below of a non-limiting exemplary embodiment thereof, illustrated in the attached drawings, in which: [0009] Fig. lisa top perspective view of a thermostatic mixer with thermal bypass according to the invention; [0010] Fig. 2 shows a vertical section of the mixer of fig. 1; [0011] Fig. 3 is a top view of the mixer of fig. 1; [0012] Fig. 4 is an axial section view of the mixer of fig. 1; [0013] Fig. 5 shows the detail A of fig. 4; [0014] Fig. 6 shows the detail B of fig. 4; [0015] Fig. 7 is the same axial section view of fig. 4 of the mixer of fig. 1, with the mixer in a particular operating position; [0016] Fig. 8 shows the detail A’ of fig. 7; [0017] Fig. 9 shows the detail B’ of fig. 7;

AH25(12531411 1):MSL 3 2017200743 03 Feb 2017 [0018] Figs 10-14 show a tool associated with the mixer of fig. 1, respectively in a perspective top view, in a perspective bottom view, in a front view, in a side view, and in a rear view; [0019] Figs 15-17 show in a perspective view the use of the tool of figs 10-14 on the mixer of fig. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The illustrated thermostatic mixer with thermal bypass, indicated generally by 10, has a valve body 11 in which a cold water inlet 12, a hot water inlet 13, a mixing chamber 14, and a mixed water outlet 15 connected to the mixing chamber 14 are obtained.

[0021] Inside the mixing chamber 14 a thermosensitive actuating device 16 of elongated shape is installed, which expands or reduces according to the temperature.

[0022] To the device 16 a cup-shaped shutter 17 is fixed, which is intended to be moved axially on the action of the device 16.

[0023] During axial movement of the shutter 17, the cylindrical wall of the shutter 17 alternatively opens or closes an upper port 18 communicating with the cold water inlet 12 and a lower port 19 communicating with the hot water inlet 13.

[0024] In the upper part the body 11 is sealingly closed by a threaded hollow head 20 that is screwed into a bush 21 that is in turn screwed into the valve body 11. In order to screw the head 20 into the bush 21, the head 20 has an upper end 22 shaped as a nut. In order to lock the head 20 onto the bush 21, an outer nut 23 is provided.

[0025] The axial movement of the shutter 17 brings the shutter 17 to abut below against an inner seat of the body 11 and above against an inner seat of the bush 21.

[0026] In the head 20, a piston 24 is sealingly slidably fitted in the axial direction, which piston 24 at one side abuts against the upper end of the device 16 whereas at the other end it extends outside the valve body 11.

AH25(12531411_1):MSL 4 2017200743 03 Feb 2017 [0027] On the actuating device 16 a biasing spring 25 acts, which is coaxial with the device 16 and located at the lower part of the inside of the body 11. This spring 25 tends to take the shutter 17 that is integral with the device 16 to the cold water closed position.

[0028] On the other hand, on the piston 24 an overrun spring 26 acts, which is coaxial with the piston 24 and located inside the head 20. This spring 26, which is stiffer than the spring 25, opposes elastically the expanding action of the actuating device 16.

[0029] To the protruding end of the piston 24 a gripping pin 27 is fixed transversely that traverses the piston 24 in such a manner that the ends thereof protrude from the piston 24.

[0030] The valve 10 is first calibrated before use to obtain the required temperature of the mixed water at the outlet 15. For this calibration, the nut 23 is loosened and the head 20 is screwed or unscrewed by acting on the nut-shaped end 22 so as to move the piston 24 axially and then to move the device 16 with the shutter 17 accordingly. In this manner, the shutter 17 is placed in a position that is such with respect to the inlet ports 18 and 19 as to make the mixture so as to obtain mixed water at the required temperature at the outlet 15. After adjustment, the nut 23 is tightened.

[0031] In use, the device 16 moves the shutter 17 according to the temperature of the mixed water so as to maintain such a temperature constant. The stroke of the shutter 24 is of minimal size and figs 4-6 show this shutter 24 in an intermediate position in which it maintains a certain distance from both the lower abutting seat and from the upper abutting seat. The piston 24 constitutes a fixed reaction point for the device 16 in thermal expansion and reduction; in the expansion of the device 16 the shutter 17 lowers, opposing the action of the spring 25, whilst in the reduction of the device 16 the shutter 17 rises on the action of the spring 25.

[0032] When the mixer 10 is used for the thermal disinfection that was discussed in the introduction, the following procedure is followed.

[0033] The shutter 17 has to be moved until it abuts against the upper seat so as to close the port 18 and maintain open only the port 19 so as to prevent the flow of cold water and permit only the flow of hot water to the outlet 15 for the thermal disinfection of the plant in which the mixer 10 is installed. In order to move the shutter 17, the piston 24 is lifted and moved away from the contact with the device 16, as illustrated in fig. 7. Lifting and moving away the piston 24 in fact

AH25(12531411 1):MSL 5 2017200743 03 Feb 2017 releases the spring 25, which pushes the device 16 and the shutter 17 upwards, the latter abutting against the upper abutting seat, as well illustrated in fig. 8. In this position, the shutter 17 is moved by a maximum from the lower abutting seat, as shown in fig. 9. By performing this operation, the device 16, even expanding, is no longer able to oppose the spring 25.

[0034] To lift the piston 24, the gripping pin 27 is grasped from the outside through a tool.

[0035] In figs 10-14, a gripping mechanical key 50 is shown that is associated with the valve 10 and designed for performing the dual function of adjusting the temperature (tightening/loosening the head 20) and of thermal bypass function (lifting the piston 24). The key 50 has a flat body and has a ring end 51 and an end 52 with a double hook. The ring end 51 has a polygonal hole 53 for tightening/loosening the head 20. The double hook end 52 provides a pair of parallel hooks 54, each having a U-shaped profile, to hook the pin 27.

[0036] The use of the key 50 is shown in figs 15-17.

[0037] In fig. 15, the use of the key 50 for tightening/loosening the head 20 (temperature adjustment) is shown. The ring end 51 of the key 50 is inserted on the nut 22 end of the head 20, such that the polygonal hole 53 mates with the profile of the nut end 22. At this point, by rotating in one direction or the other, the head 20 is tightened or loosened, calibrating the mixer 10. The head 20 is then locked by the nut 23.

[0038] In figs 16, 17, the use of the key 50 to lift the piston 24 (thermal bypass) is shown. In this case the two ends of the pin 27 are hooked with the two hooks 54 of the key 50 and the key is rotated around the pin 27 so as to exert traction on the pin 27 that lifts the piston 24. The rotation is completed when the base 55 of the U-shaped profile of the hooks 54 is positioned against the head 20 as shown in fig. 17.

[0039] In order to return to the function of thermostatic mixer, the key 50 is rotated in the opposite direction and is removed from the pin 27.

[0040] The main advantage of the disclosed and illustrated mixer 10 is that the calibrating parameters are never modified by passing from the “thermal bypass” function to the “thermostatic mixer” function. In fact, the angular position of the head 20 is not altered inasmuch, as has been seen, only the piston 24 is acted upon.

AH25(12531411_1):MSL 6 2017200743 03 Feb 2017 [0041] This is all obtained with a simple structure for the mixer and the mixer components and thus with a low production cost.

[0042] The key 50 proves to be particularly effective through the dual function thereof. Further, the U-shape of the hooks enables a specific stroke of the piston 4 to be defined, which is shown in sequence by figs 4,7; this ensures that the piston 24 moves away from the device 16 and thus the shutter 17 totally prevents the flow of cold water.

[0043] It is clear that variations on and/or additions to what has been disclosed and illustrated can be provided.

[0044] The configuration of the mixer and of the components thereof can vary according to needs.

[0045] Instead of the pin 27, any gripping element can be used that enables the piston to be grasped and raised to the correct height. In order to ensure that the piston is moved away from the driving device, reference markings on the piston can be used.

[0046] Further, any type of tool can be used that enables the piston to be grasped and raised to the exact height, even if the key disclosed and illustrated, as seen, is particularly effective.

AH25(12531411_1):MSL

Claims

1. A thermostatic mixer with thermal bypass comprising a valve body in which are obtained a cold water inlet, a hot water inlet, a mixing chamber, and an outlet of mixed water connected to the mixing chamber, wherein inside the valve body a thermosensitive actuating device is installed which expands or reduces according to the temperature and to which a shutter is fixed that moves axially on the action of the device to adjust the flow of hot and cold water into the mixing chamber so as to have at the outlet a water mixed at a presettable determined temperature, wherein the mixer comprises a piston against which the device abuts, first elastic means acting on the device in the direction of the piston and second elastic means acting on the piston in direction of the device, wherein the piston has an end protruding outside the valve body and provided with external gripping means for grasping and moving the piston away from the device, causing the movement of the shutter on the action of the first elastic means in a position of stopping or reducing the flow of cold water to perform the function of thermal bypass.

2. The thermostatic mixer according to claim 1, wherein said external gripping means comprises a pin fixed transversely to the piston, which traverses the piston so that the ends thereof protrude from the piston.

3. The thermostatic mixer according to claim 1 or 2, to which a tool is associated that couples with the gripping means to grasp and remove the piston.

4. The thermostatic mixer according to claim 1 or 2, wherein the piston is mounted slidably in a head that is screwed in a lockable manner in the valve body to preset the temperature of the mixed water.

5. The thermostatic mixer according to claim 4, wherein the head comprises a portion shaped as a nut.

6. The thermostatic mixer according to claim 5, to which a tool is associated that is configured in such a manner as to couple with both the portion shaped as a nut and with the gripping means.

7. A mechanical key for use in association with the thermostatic mixer as claimed in claim 5, comprising a ring end with a polygonal hole for the coupling with the portion shaped as a nut of the head to tighten/loosen the head and further comprising an end with a double hook for hooking the gripping means and moving the piston away from the device.

8. The mechanical key according to claim 7, wherein the double hook end has a pair of parallel hooks each having a U-shaped profile.

9. A kit comprising the thermostatic mixer according to claim 5 and the mechanical key according to claim 7 or 8.