US 3848800 A
A complex booster including a four-port mixer-valve is associated with a reduction-gear micromotor controlled by a signal from a room thermostat, in such a manner as to form a single-piece apparatus which is compact and easy to insert into a central heating installation. In addition, the complex booster is provided with a hydraulic regulator to select the most appropriate pressure-flow pump characteristic and thus a suitable operation point. Alternatives available include one in which a booster, mixer-valve and micromotor are arranged in line and two others wherein the booster is a side mixer-valve plus micromotor. The two last alternatives have advantages as to accessibility and maintenance and are easier to install in avoiding numerous pipe bends.
Description (OCR text may contain errors)
United States Patent 1 [111 Y 3,848,800
Perche Nov. 19, 1974  BOOSTER FOR CENTRAL HEATING 2,404,597 7/1946 McClain 237/8 C INSTALLATION WITH AUTOMATIC 3,228,656 1/1966 Kyogoku 415/158 REGULATION Inventor: Maurice Perche, Boulogne, France Assignee: ITT Industries, Inc., New York,
Filed: Sept. 27, 1972 Appl. No.: 292,647
Foreign Application Priority Data Sept. 28, 1971 France 71.34765 Nov. 26, 1971 France 71.42351 Mar. 30, 1972 France 72.11173 References Cited UNITED STATES PATENTS 11/1919 Moody ..415/158 Primary Examiner-Edward G. Favors Attorney, Agent, or Firm-D. P. Warner; J. B. Raden [5 7] ABSTRACT A complex booster including a four-port mixer-valve is associated with a reduction-gear micromotor controlled by a signal from a room thermostat, in such a manner as to form a single-piece apparatus which is compact and easy to insert into a central heating installation. In addition, the complex booster is provided with a hydraulic regulator to select the most appropriate pressure-flow pump characteristic and thus a suitable operation point. Alternatives available include one in which a booster, mixer-valve and micromotor are arranged in line and two others wherein the booster is a side mixer-valve plus micromotor. The two last alternatives have advantages as to accessibility and maintenance and are easier to install in avoiding numerous pipe bends.
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sum 110F12 BOOSTER FOR CENTRAL HEATING INSTALLATION WITH AUTOMATIC REGULATION The present invention relates to booster pumps for circulating a fluid through a circuit and, in particular, to those booster pumps which are employed to boost circulation of heat exchange fluids through central heating facilities provided with automatic regulation.
Usually, a valve-pump and a first electric driving motor are coaxially mounted inside a single housing to boost circulation of heat exchange fluid through a central heating installation. Such valve-pumps may have several ports for providing heat exchange fluid circulation through a channel or another channel between the boiler and the set of radiators. The valve-pump may be driven at, either constant or variable, rotation speed. Variable speed driving enables pressure-flow pump characteristics to change and an operation point to be selectively defined on one among the possible characteristics. The plurality of pressure-flow characteristics, on which an operation point may be selected for the pump, may be produced in a different manner by operating a control cock which controls flow through a feedback pipe provided through an internal pump circuit. Selection of a predetermined characteristic is achieved by operating from outside of the valve-pump housing a rotative device such as a screw head integral with the rotatable member of the said control cock.
Presently, automatic control is more and more required for operating central heating facilities in accordance with temperature changes. To meet those requirements, there is, in addition thereto, provided a second so-called regulation motor which controls the booster, including the properly-said pump and the mixer valve in accordance with data received from responsive devices such as a detector of the thermostat type, probe, etc., and compared with a predetermined reference temperature.
As the booster is controlled by a second electric regulation motor, it is necessary to provide the central heating installation, either with two separate items, i.e., booster and regulation assembly fitted to control the booster, or with a complex booster apparatus including the properly-said booster plus the regulation assembly. In either case, the regulation assembly is usually constituted by a costly, bulky motor-reduction gear assembly. Every day, building, as other engineering branches, requires more and more size reduction, which causes manufacturers to seek small sized devices. Factory cost is also to be taken into account in such developments.
To meet those requirements, according to the present invention, there is provided, as a new product, a booster designed to automatically boost, according to the temperature, the circulation of a fluid, particularly of a heat exchange fluid through a central heating installation, which comprises a mixer-valve-pump driven by a first motor, an hydraulic flow regulator associated to the said pump and a regulation motor-reductiongear assembly of a miniature type, which controls, in accordance with a signal resulting from comparison of the temperature valve detected by a room thermostat with a predetermined value, the operation of the mixer valve and consequently the flow rate through it, and provides an automatic temperature regulation for the said installation.
According to another feature of this invention, the hydraulic flow regulator, associated to the booster pump, consists of an adjustable cock mounted in a feedback pipe from pump impeller cavity in the pump body.
According to another feature of this invention, the valve-pump of the booster apparatus includes a multiport mixer valve such as a four-port valve.
According to another feature of this invention, the motor-reduction-gear assembly of the booster apparatus consists of an electric micromotor coupled to a planet-wheel speed-reduction-gear, whose input is provided with first means meshed with the micromotor shaft and whose output is provided with second means coupled to the mixer-valve control for regulating input fluid flow at a temperature predetermined for entering the main installation network and which is provided with third means for possibly transmitting control data to electric supply and control circuit, this electric supply and control circuit being provided with fourth means for initiating start, rotation direction and stop of the micromotor responsive to the received control data.
Usually, such a booster apparatus is so designed that the valve-pump shaft and the micromotor-reductiongear shaft are aligned in a common direction, one behind the other with the result that, on the one hand, input and output ports thereof look like located at the ends of a cross and, on the other hand, the hydraulic flow regulator control screw may be located in the space between the booster body front face and the reductor box rear output face. Such a structure may have drawbacks. Obviously, the crossed port structure is not the more attractive as far as occupied room is concerned, it is not the more suitable because it results in angled coupled pipes. Moreover, the space wherein the said control screw is often located, has small sizes which results in a bad access to the screw.
A purpose of this invention is to overcome those drawbacks in providing improvements to such a structure.
According to this invention, there is provided a booster wherein the properly-said booster, the micromotor-reduction-gear and the hydraulic flow regulator control are such that booster shaft is parallel to a micromotor-reduction-gear shaft and that hydraulic flow regulator control is located on the front face and easily accessible, and wherein input and output ports to be coupled to installation pipes have all vertical parallel axes and are located in the rear portion.
Otherwise said, the booster apparatus according to this invention is substantially H-shaped, input and output ports being located at the ends of the H arms and legs.
According to this invention, an arm-leg couple of the H coincides with the vertical pump symmetrical axis while the other arm-leg couple coincides with the vertical micromotor-reduction-gear symmetrical axis. In ad'- dition thereto, a clutch may be provided between the output shaft of the micromotor-reduction-gear and the mixer-valve control, the clutch being provided with manual control means with a return spring.
According to another feature of this invention, the hydraulic regulator is located downstream with respect to the mixer valve, with the result of a better efficiency.
Indeed, when located downstream regarding the mixer valve, the hydraulic regulator regulates the whole fluid flow since it influences the flow mixed in the mixer valve. If located upstream regarding the mixer valve, the regulator involves only the part of the flow processed in the booster-pump, that part of the flow coming from the boiler. It results from efficiency comparison for a same hydraulic regulator that upstream position efficiency is less than downstream position efficiency, except in the particular case where the total ingoing flow is processed that is with no mixing operation.
It is a further purpose of this invention to provide a single apparatus forming a small-sized compact block having in a central heating installation the following functions:
boosting heat exchange fluid flow,
hydraulically varying pump characteristics,
automatically regulating temperature, and
providing protection against corrosion.
Other purposes and features of the present invention will appear more clearly from the following description of embodiments, the said description being made in conjunction with the accompanying drawings, wherein:
FIG. 1 is a general cross-sectional view of a first embodiment of a booster apparatus according to this invention,
FIG. 2 is a cross-sectional view along the line 22 of the embodiment shown in FIG. 1,
FIG. 3a is a schematic bottom view of the micromotor-reduction-gear assembly,
FIG. 3b is a schematic diagram of the planet-wheel set in a plane normal to the speed reduction-gear shaft,
FIG. 4 is a schematic diagram illustrating how the embodiment shown in FIG. 1 is mounted in a central heating installation provided with a room thermostat,
FIG. 5 is a front view of a second embodiment of a booster apparatus according to this invention,
FIG. 6 is a cross-sectional view in a horizontal plane passingby the booster pump motor axis as well as by the micromotor-reduction-gear axis, along the line 6-6 of FIG. 5,
FIG. 7 is a vertical cross-sectional view of the booster, along the line 7-7 of FIG. 5,
FIG. 8 is a horizontal cross-sectional view of the apparatus along the line 8--8 of FIG. 6,
FIG. 9 is a vertical cross-sectional view in the plane of the vertical symmetrical axis common to upper and under ports and to the micromotor-reduction-gear assembly, for a third embodiment according to this invention,
FIG. 10 is a schematic cross-sectional view of a fourth embodiment of a booster apparatus according to this invention,
FIG. 11a is a front view of the apparatus shown in FIG. 10,
FIG. 11b is a front view of an alternative of the apparatus shown in FIG. 10, provided with automatic control means,
FIG. 12 is a cross-sectional view of the mixer-valve branch of the apparatus shown in FIG. 11b, and
FIG. 13 is a schematic diagram illustrating how the embodiment shown in FIG. 11b is mounted in a central heating installation.
As it appears from FIG. 1, the booster apparatus consists of two coaxially mounted parts: the regulation micromotor-reduction-gear assembly 10 and the booster 20. The booster 20 includes a pump and a mixer-valve inside a pump housing 23. In the embodiment shown in FIG. 1, the illustrated valve-pump is provided with four ports, as shown with details in the crosssectional view of FIG. 2, taken along line 22 of FIG. 1. More particularly, FIG. 2 shows the rotatable segment valve T which enables the various channels to communicate.
In FIGS. 1 and 2, the same reference numerals indicate the same components; the following description is first made with reference to both figures. In valvepump 20, the impeller 21 is secured to one end of the motor shaft 22. The main fluid circuit comprises a first region, called input port E, a second median region M and a third region S, called output port designed for connection with an external pipe. The derived circuit comprises a ring cavity 25 adjacent to the paddles of impeller 21. That volute-shaped cavity, called impeller cavity, is provided with a port 0, which can only be seen in FIG. 2, which causes it to communicate with the main circuit, as shown, via the feedback pipe 24. The rotatable segment valve T is driven by reduction-gear output shaft 8 by means of coupling means 28. When the pump is unoperative, the fluid entirely flows between E and S along the path EMS with a negligible loss of pressure. When the pump is operative the main flow from port S is accelerated by the impeller 21. A part of the flow derived in the impeller cavity 25 is sent back through port 0 and feedback pipe 24 toward the main circuit in the median region M and finally flows out with the main flow through port S.
For adjusting flow rate and selecting the flowpressure characteristic of the pump, a cock 27 regulates the aperture size of the port 0 of impeller cavity 25 in response to rotation of screw head 26 integral to the cock 27. The screw head 26, which controls the position of cock 27, is level with the housing body of the pump 23 which includes the various components which have been hereabove described.
In the embodiment of the FIGS. 1 and 2, the hydraulic regulator control screw head 26 is located on the same side as coupling means 28 between valve-pump 2 and regulation assembly 10, in an accessible location. It is rotatable in front of a predetermined scale so as to render easier the selection of the flow-pressure characteristic of the pump.
The valve-pump is driven by a first electric motor 29, located inside the pump housing 23 and illustrated by a dotted line in the FIG. 1.
In the described embodiment, the micromotorreduction-gear assembly 10 is directly coupled by 28 to the rotatable segment valve T of the valve-pump 20, the output reduction-gear shaft end being toothed to mesh with the sleeve 30 integral with, for instance, the segment valve T. Such a coupling means, called sleeve coupling, or any other coupling means may be pennanent. In alternatives, if it is designed for being used only when automatic regulation is operative, such a coupling means may be a direct-drive dog-clutch secured to the output reduction-gear shaft, for example.
In the longitudinal cross-sectioal view of the FIG. 1, there are illustrated, inside the general housing 11, an electric micromotor l, a speed planet-wheel reductiongear 4 and an electric circuit C providing power supply and control to the micromotor l. The shaft 2 of motor 1, which rotates with easy fit in the selflubricating bearing 9, carries a driving toothed wheel 3 which meshes directly with a set of three planet-wheels such as r, angularly spaced at 120 from one another in a plane normal to the driving shaft. That first set constitutes the first reduction stage of the reduction-gear 4. Reduction-gear 4 includes four three-planet-wheel reduction stages. Each of the planet-wheels of the said stages, such planet-wheels r, r", r, FIG. 1, freely rotates on a shaft secured to a bearing plate associated to the stage, such as the plate 5 with which the shaft associated to the planet-wheel r may be casted. The fixed body 6 has an internal fixed toothed ring 7 which meshes with planet-wheels r, r", r', r of each reduction stage. The output reduction-gear shaft 8, which rotates with easy fit in the selflubricating bearing 12, carries cam 13 whose pattern may push the mobile contact 14 of a first switch 15 of a miniature type. The same cam is so shaped that, when its pattern pushes the contact 14 of the first switch 15, it releases the mobile contact 14 of a symmetric switch 15'.
The FIG. 3a illustrates schematically the micromotor-reduction-gear assembly as it appears from a point located below it.
The electric circuit C is connected, as shown, to other components illustrated in the FIG. 1. The wire C' is connected to a first terminal h of the miniswitch 15 whose second terminal f is connected at g to the connecting bar 16; in addition the first terminal h is connected to a capacitor 17. Capacitor 17 is connected to the first terminal d of the second miniswitch 15; that terminal d is, in addition, connected to the wire C from the FIG. 1. A second terminal e of the miniswitch 15 is connected at i to the connecting bar 16 which is supplied by the mains. The mobile contacts 14 and 14 may be alternatively pushed by the pattern of the cam 13. e
The FIG. 3b is a schematic view, in a plane normal to the motor shaft, of a set of planet-wheels forming a reduction stage. The teeth of the driving pinions carried by the driving shaft may be seen in 3. The three planet-wheels are angularly spaced by I20", W W W and mesh, on the one hand, the fixed teeth carried by the body 6, FIG. 1, and on the other hand, the pinion 3. The rotation speed, which is reduced by the first set of planet-wheels, is transmitted to the second set form- 'ing the next stage, and so on. The teeth 3 of the driving pinion is only used by the first set of planet-wheels.
That assembly operates as follows. The micromotor shaft 2 drives the pinion 3 and consequently the first set of planet-wheels. For the following stages, the reduced rotation speed is transmitted from the fixed teeth 7 of the body 6 from that of the first set of planet-wheels, and so on, up to the reduction-gear output. The miniswitches l5, 15, secured to the general housing 11, permit to stop the micromotor by means of cams, when any limit position has been reached. Such a cam may be the cam 13 secured to the control shaft 8. Thus, by means of the cam 13, it it possible to modify angular rotation of shaft 8 and to determine the micromotor rotation direction. Should an electric single-phase motor, a capacitor 17, FIG. 2, is added between the two miniswitches l5 and 15'. That capacitor, in a conventional manner, shifts phase of the coil windings. Finally, the reduced rotation speed is produced to be utilized at the point 28 for coupling mixer valve control means.
The FIG. 4 illustrates how the apparatus, according to this invention, may be used in a central heating installation, which includes a boiler 41, a booster apparatus 42, according to this invention, a radiator 43, symbolizing a set of radiators, a water tank 44, a room thermostat 45. The booster port E is used as an inlet for heated water from output of boiler 41 while booster port A is used an an outlet for circulated heated water to radiator 43. Cooled water from radiator 43 enters booster 42 through inlet port B, which avoids cooled water from directly returning to boiler 41 and, as a result therefrom, boiler corrosion. Cooled water is mixed with heated water from inlet E and sent back, at a mean temperature avoiding strong corrosion, to the boiler 41 through outlet S. The micromotor-reduction-gear of apparatus 42 receives data from room thermostat 45. A secondary circuit for heating water tank 44 may be possibly mounted in parallel to the first circuit. Return of water, to be heated again, is separated or not from mixed water return from radiators after having passed through the booster.
The FIG. 5 shows details of a second embodiment of a booster apparatus according to this invention. The same reference numerals will be used for indicating the same components as in FIGS. l-4. Booster 20 is arranged in a parallel direction to micromotor-reductiongear assembly 10. Axis O of 10 and axis 0' of 20 are located in a common horizontal plane 6-6.
Both motor of booster 20 and micromotor of 10 are located at the front side of the apparatus. So it is for control screw of hydraulic variator which appears on the front side below the booster motor. Inlets and outlets are indicated by reference numerals 31, 32, 33 and 34; they are located at the rear side of the apparatus and oriented along two parallel vertical axis.
FIG. 6 is a horizontal cross-sectional view of the apparatus along plane 66 defined by the above mentioned axis 0 and O. The right portion of FIG. 6 shows details of micromotor-reduction-gear assembly 10 which is similar to that of FIG. 1. Output axis 28 is directly coupled to axis 18 of the mixer valve.
FIG. 7 is a vertical cross-sectional view of the booster of the second embodiment, along the line 7-7 of FIG. 5. To be noted that hydraulic variator 27, controlled by screw 26, is substantially the same as the one shown in FIG. 1.
FIG. 8 is a horizontal cross-sectional view of the paaratus along line 8-8 of FIG. 6, at the level of the junction between the two branches of the I-I-shaped structure determined by inlets and outlets. A butterflyvalve V is used instead of rotatable segment valve T of FIG. 2, but fulfills the same function while its structure is considerably simplified.
General operation of this second embodiment, as illustrated in FIGS. 5-8, is the same as that of the first embodiment, as hereabove described. Booster-pump flow-pressure characteristic is controlled by operating screw 26. Rotation of mixer valve V is controlled by micromotor-reduction-gear assembly 10 with direct coupling of output assembly shaft 28 and valve axis 18 (i.e., butterfly-valve) as shown in FIG. 5. Operation of assembly 10 is controlled by a signal resulting from the difference between one preset temperature and another one detected in the heated room, for example. Temperature control may be either digital or proportional. In a preferred temperature control embodiment, a proportional control has been achieved wherein a thermistor detects boiler output flow temperature, another thermistor detects temperature in the room to be heated by means of a room thermostat while a predetermined preset temperature serves as a reference. Temperature changes are signaled by thermostat to micromotor which operates in response thereto and rotates the mixer valve which is positioned in accordance with the requested thermal load. For balancing the constant gap due to proportional control, a probe is incorporated into the external temperature measure bridge so as to maintain room temperature constant.
The main advantages of this second embodiment are that its mounting is very similar to standard booster mountings, particularly with respect to means for securing it to a wall. All mechanical and electrical components are accessible on the front side. The apparatus is less bulky, it may be more easily machined and mounted in the field.
FIG. 9 shows a third embodiment of the booster apparatus according to this invention, wherein the components are arranged in a different manner. While in FIG. 5, axis does not cross the vertical symmetry axis of ports 32 and 34, in this third embodiment they are crossing. Moreover, for rendering easier the maintenance of assembly 10 and, possibly, the interchange of components without stopping heating operation, a clutch 30 is inserted between shaft 28 and shaft 18. Clutch 30 includes a control handle 35 the position of which is determined by spring 36 secured to handle 35 and held by pin 37 in engagement condition.
This apparatus operates as follows:
In engaged condition, spring 36 is held in a position which provides a perfect coupling of output shaft 28 and valve shaft 18, due to the fixed pin 37. In disengaged condition, spring 36 is free from pin 37, is curved at its free end toward handle 35 and shafts 28 and 18 are disconnected.
In addition to all the previously mentioned advantages, specific ones of this third embodiment are easier machining and mounting as well as much easier maintenance in case of failure.
FIG. 10 is a schematic cross-sectional view of a fourth embodiment of a booster apparatus according to this invention. With respect to the H-shaped structure of FIG. 5, H-shaped structure shown in FIG. 10 is symmetrical, that is booster motor appears now in the right section while mixer valve appears in the left one. The four-port butterfly-valve V has a circular cross-section wherein a butterfly 46 is rotatable around an axis 0. Impeller 21 of booster 20 rotates in impeller cavity 25, located in the middle right section. Impeller axis is indicated in 0'. High in the middle of the structure, located is a feedback pipe 47-48. Portion 47 of this feedback pipe is cylindrical with an axis 0. A cock 55 is rotatable around axis O for opening more or less pipe portion 48. As shown in FIG. 10, pipe portion 48 is entirely closed by cock 55.
The four ports of the booster apparatus comprise an inlet E for fluid from boiler 41, outlet A for fluid to central heating installation, i.e., to radiator 43, on the right side, and inlet B for fluid from radiator 43 and outlet S to boiler 41, on the left side.
The front view of FIG. 11a shows an alternative provided with manual control by means of handle 49 rotatable around axis O. Handle 49 operates butterfly 46, as shown in FIG. 10. In the middle of the right section, there is a front view of motor 20 of the booster. Screw 47 for controlling the hydraulic variator may be rotated before a scaled sector.
The front view of FIG. 11b shows another alternative provided with automatic control comprising manual control handle 49, motor of control micromotorreduction-gear assembly superimposed to handle 49, and the same components as shown in FIG. 11a.
FIG. 12 shows a cross-sectional view of the left branch of the apparatus shown in FIG. 11b. Particularly, FIG. 12 shows the arrangement of the micromotor-reduction-gear assembly provided with a clutch. Axis O 0 of butterfly 46 coincides with axis of shaft 102 of the said assembly and is connected to it by means of clutch 50. Handle 49 is made secured to the automatic arm p by any known means, such as for example a spring leaf 104 provided on both sides by a bolt-screw system, a pin-and-socket system, etc. Preferably, close to output of shaft 102, a recess 103 facilitates mounting of clutch 50. Handle 49, secured to automatic arm p integral with shaft 102 may be freely rotated within recess 103.
FIG. 13 shows a diagram of a domestic central heating installation provided with a booster apparatus according to this invention and comprising, the same reference numerals being used as in FIG. 4, boiler 41, booster 51, radiator 43, hot water tank 44, temperature probe t, regulation device 52, electric power supply 53 and room thermostat 54.
Such an installation operates as follows: hot fluid from boiler 41 enters booster 51 via inlet E and circulates inside the booster as indicated by the arrows. From inlet E, fluid flows toward butterfly-valve V wherein it is mixed with fluid from radiator 43 via inlet B, then mixed fluid enters impeller room 25, feedback pipe 47-48 being closed, and is boosted to radiator 43 via outlet A. Rotation of control screw 26' of hydraulic variator, as shown in FIGS. 11a and 11b, permits to open feedback pipe by rotating the cock and thus to select the most suitable flow-pressure characteristic for the booster.
For summarizing, the functions fulfilled by the booster apparatus according to this invention are the following:
1. boosting central heating fluid flow which improves installation efficiency,
2. hydraulically varying pump characteristics; adjusting means consisting of an adjustable cock mounted in an auxiliary fluid path in the valve enables pressureflow operation characteristic range for the booster to be enlarged and provides a great flexibility in selecting the operation point,
3. self-regulating installation temperature by means of a micromotor-reduction-gear assembly, and
4. protecting the boiler against corrosion due to a plurality of inlets and outlets which permit to avoid direct cold water return to the boiler.
In addition to the above mentioned advantages, the apparatus being made of one housing, is small sized and easily inserted into an installation and is less expensive than a plurality of various devices as nowadays for the same functions.
While the principles of this invention have hereabove been mentioned in relation with several specific examples, it must be clearly understood that the said description has only been made by way of example and does not limit the scope of this invention.
What is claimed is:
1. Booster apparatus for automatically controlling the circulation of fluid in a heat exchanger system, COmpl'lSlIlg a pump adapted to be connected to a fluid circulating system,
a first motor coupled to drive said pump,
a hydraulic flow regulator mounted in said pump to enable selection of flow-pressure characteristics of said pump and thereby a suitable operation point,
a rotatable valve associated with said pump to control the flow rate through the pump,
a second motor coupled to control the position of said rotatable valve,
control means responsive to signals from thermostatic control means to position said second motor and said rotatable valve and control flow through the pump accordingly, and
means positioning the pump, the first motor and the second motor together in a common housing.
2. The invention according to claim 1, in which the pump includes a port positioned between a pump impeller cavity and a connection pipe through the pump, and
the hydraulic flow regulator consists of an adjustable cock mounted in said port.
3. The invention as claimed in claim 1, in which the valve is a multi-port valve.
4. The invention as claimed in claim 1, in which the second motor consists of a micromotor, and
the micromotor is equipped with speed reduction means to regulate the position of the rotatable valve.
5. The invention as claimed in claim 4, in which the speed reduction means includes a planetary-gearspeed reduction means, and
the micromotor is connected to the planetary-gearspeed reduction means via a driving pinion secured to the micromotor shaft.
6. The invention as claimed in claim 1, in which the rotatable valve is coupled to the second motor by a sleeve coupling device whereby the end of the motor output shaft is inserted in a sleeve integral with the rotatable valve.
7. The invention as claimed in claim 4, in which the control means includes a cam secured to the output speed reduction means and having a pattern so as to operate at least a switch to modify the on or off condition of the second motor.
8. A booster apparatus according to claim 1, in which said hydraulic flow regulator is located in the hydraulic circuit after the rotatable segment valve for processing mixed fluid.
9. A central heating installation with automatic temperature regulation including a booster apparatus according to claim 5, in which the micromotor-reduction-gear assembly operates a multi-port rotatable segment valve.
10. The invention as claimed in claim 1, in which the rotatable valve is a butterfly-valve to which the motor is coupled through a reduction-gear assembly, and
the micromotor is responsive to a signal proportional to a difference in temperature from a desired level to adjust the position of said butterfly valve.
11. The invention as claimed in claim 1, in which the said reduction-gear assembly includes an output shaft which is coupled by a clutch to the rotatable valve.
12. A booster according to claim 11, in which a handle is rigidly joined to a shaft of the rotatable valve.
13. A booster according to claim 12, in which control is manually performed by said handle.