US2894689A - Thermally sensitive valves - Google Patents

Description

H. E. sPlcER l-:TAL 2,894,689

THERMALLY SENSITIVE VALVES Jgly 14, 1959 2 Sheets-Sheet 1 Filed NOV. 29, 1957 F/GJ.

July 14,A 1959 H. E. sPlcER ETAL ATrim/[ALLY SENSITIVE VALVES 2 Sheets-Sheet 2 Filed Nov. 29, 1957 HAROLD E. sP'lrca-:R ROBERT CROSBY .FRsoERlcK .Ag SIMPSON nvenlvors Attorneys United States Patent On l 2,894,689 Patented July 14, 1959 ice 2,894,689 THERMALLY SENSITIVE VALVES VApplication November 29, f1957, Serial No. 699,684

Claims priority, application Great Britain December 3, 1956 5 Claims. (Cl. 236-345) The present invention relates to thermally controlled valves of the kind in which one or more valve ports are opened and closed by means of a rotary member which is turned by means of a thermally sensitive element.

In one known construction a Valve of this type comprises a cylindrical casing having three ports at substantially equiangular spacing around its curved periphery and a rotor carried on an axially arranged spindle, the rotor carrying two arcuate shutter members arranged diametrically opposite to each other. One port is always open and the rotor is permitted to rotate through a limited angle from a position in which one of the remaining ports is obscured by one shutter member through positions in 'which both ports are partially obscured to a position in which the third port is obscured by the other shutter member and the second port is fully open. The rotor is turned by means of a thermally sensitive element located within the valve casing and exposed to the lluid passing through the valve casing.

Valves of this type are employed, for example, for the control of the temperature of the coolant of an engine, one of the two closable ports being connected to a radiator or other heat exchanger Whilst the other port is connected to a by-pass leading back to the engine, so that with rise and fall of the temperature of the coolant entering the valve from the engine, a greater or less proportion of coolant is passed through the radiator or other heat exchanger.

Such valves are usually arranged so as to pass from a position in which all the coolant is by-passed to a position in which all the coolant is directed to the radiator or other heat exchanger within a relatively narrow temperature range, so as to maintain the temperature of the coolant substantially within this predetermined range during normal operation of the engine.

It will be appreciated that since the optimum operating temperature is not the same at all times for all engines, it is desirable to provide means for adjusting the valve operation to different temperature ranges so as to permit of variation of setting if necessary during operation of the engine.

It is an object of the present invention to provide a valve of this type in which the rotor is held in an angular position determined by the temperature of the incoming uid and cannot oscillate about such position to any appreciable extent.

It is a further object of the invention to provide a thermostatically controlled valve with a simple means for adjusting the commencement of the operating temperature range within which the valve rotor is subjected to movement.

Although temperature sensitive elements of the bimetal type are known which will act directly to provide an angular force, the force provided by these is relatively Small and such elements have a tendency to oscillate.

Linearly expanding thermosensitive elements provide, for their size, far greater forces and have little or no tendency to oscillation.

In its broadest aspects the present invention provides a thermally controlled valve comprising a housing having at least one port controlled by a member rotatably mounted in the housing, the said member being rotatable Within the housing by means of a linearly expanding thermosensitive element located axially of the housing, and a coupling means adapted to convert linear movement into rotary movement, one of the coupling means or the thermosensitive element being non-rotatably connected to the rotatable port-controlling member, whilst the other is non-rotatably connected to the housing.

A suitable form of coupling means for the present purpose comprises a member having a helical cam groove therein for engagement with a pin. The pin is preferably carried by the thermosensitive element to engage Iwith a helical cam groove in a sleeve, but obviously alternative arrangements are possible, such as having the cam groove on the outside of a part of the temperature sensitive element. In another alternative a part of the thermosensitive element is bored out to t over a rodlike coupling member, the pin then being carried either by the coupling member or the thermosensitive element.

In order to provide a means for rendering the thermo sensitive element ineffective to turn the shutter member, the cam groove may have terminal portions parallel to the axis of the rotatable port-controlling member at one or both ends of the middle helical portion. The pin may be brought into engagement with the straight portions of the cam groove by longitudinal adjustment of the coupling means. If the helical portion of the cam groove is arranged so that when a linearly moving pin traverses its entire length, the rotor of a valve of the type above referred to is rotated through a substantially larger angle than the minimum angular motion required for the valve operation, it will be seen that longitudinal `adjustment of the coupling will vary the temperature range within which the valve acts.

Various constructions of a valve made in accordance with the present invention are shown in the accompanying drawings, wherein:

Figure 1 is an `axial section of a valve made in accordance with the invention.

Figure 2 is a cross section of the valve of Figure 1 without the thermosensitive operating means.

Figure 3 is a part-axial section of a valve including an emergency release means.

Figure 4 is a cross section of a different form of valve which may lbe opera-ted by means of the mechanism shown in Figures 1 and 3.

Referring first to Figure 2, there is shown a valve of generally known type comprising a casing 1 having a cylindrical bore 2, which is closed by end plates 3 which serve to support a rotor 4. 'Ihe valve casing 1 is formed as a casting lhaving three flanges 5, which connect with the cylindrical bore 2 through long narrow ports 6, 7 and 8. The arcuate shutter members carried by the rotor control the ports 7 :and 8 respectively, so that the angular position of the rotor 4 will determine in what proportions uid entering the port 6 will pass out through the ports 7 and 8.

In the construction shown in Figure l the rotor 4 is controlled by a thermosensitive element 9 of known type, in which a semi-liquid substance is held within a closed container and transmits force, on expansion, to a piston through a rubber sealing diaphragm, simultaneously com-4 pressing a spring to provide return force on contraction of the semi-liquid substance. When cold, the spring presses the piston against a stop, so that the piston does not begin to move until a predetermined temperature is reached. The spring l@ of the element 9 is shown in Figure l. The body of the element 9 is held rmly against rotational or longitudinal movement in a central web ll of the rotor 4. The piston of the element 9 actuates a rod l2, in which a laterally extending pin ld is located. The distance by which the pin ld extends from the body of the element 9 is controlled by the temperature to which the element 9 is exposed.

The rotor d has a hollow bearing boss l which is rotatably supported in relation to the end plate 3 on a sleeve member lid. The sleeve member i6 has a cam groove i7 cut therein and the boss l5 has a straight groot/1 (not visible in Figure l). The pin ld engages both grooves, so as to hold the rod i2 from twisting with regard to the rotor d, whilst at the same time producing relative angular movement between the rotor d and the sleeve ld, whilst the pin le is engaged in the inclined portion extending between points B and C of the cam groove i7.

The sleeve lo is held against rotation in relation to the end plate 3 by means of a pin l engaging a keyway i9 in the outer surface of the sleeve i6,

The longitudinal movement of the piston of the thermosensitive element 9 within its stated operating range moves the rod l2 longitudinally by a distance less than the axial distance between the points B and C, whilst the radial angle between points B and C is greater than the angle through which the rotor d turns in moving between the two alternative positions shown in Figure 2, as explained above. lt will be appreciated that whilst the pin 14 is moving longitudinally within the portion of the cam groove between the points B and C, the rotor d is turned without any appreciable utter or oscillation, because of the engagement of the pin in the groove.

On the other hand, if the pin 14 is arranged so that it slides only in the straight portions of the cam groove lying between the points C and D or the points A and B, the rotor 4 will be locked against rotary movement and will hold the valve with one of the ports 7 or 8 fully open.

The longitudinal adjustment of the sleeve i6 necessary to produce these results is eiected through the engagement of a threaded tail Ztl of the sleeve with a nut 21, held captive within a cover member Z2. This is, of course, only one of many alternative possible devices for the longitudinal adjustment of the sleeve i6,

Figure 3 shows an alternative form of valve, in which no adjustment is provided for the alteration of the temperature range. The construction shown in Figure 3 is intended to direct the flow of liquid through the valve in the most suitable direction in the event of serious overheating.

In Figure 3, like reference numerals are applied to like parts. in this construction a modiiied sleeve i6' has a slightly modified cam groove i7. The sleeve 16 is normally held so that the motion of the pin ld is between the points B and C, but in the event of overheated liquid passing through the valve, a fusible plug 2d melts to permit a sear 25 to rotate and release a lever housing 2.6. The lever housing 26 is ordinarily held against rotation by the scar, but when released it rotates under the force produced by a torsion spring 27.

The tail of the sleeve i6 is hollow and receives a portion 28 of the lever housing 26. The portion 2S has a spiral groove 2.9 formed therein and this is engaged by a pin 30, so that rotational movement of the lever housing 26 causes the sleeve i6 to be moved inwardly to a point in which the pin i4 lies within the portion between the points C and D, so as to lock the appropriate port open.

in Figure 1 3 the application of the present invention to valves of the three-port type, in which two ports are controlled by a rotor, has been shown. The invention can also be applied to similar constructions of valve, in which, for example, the controlled ports are multi-mouthed, so that the rotor controls the opening and closing of all such mouths.

Another construction of valve which may be controlled in the same way is shown in Figure 4. This is a shut-off valve having an entry port 46 in a body lll and an exit port i2 having a seating for a valve member 43 mounted on an arm M adapted to turn `about the axis 45. lf the element 9 and associated parts are rigidly mounted to turn with the arm 44 and the sleeve 16 and associated parts are mounted in the body #il in the same manner as in the cover plate 3, then the valve will shut oli automatically when the temperature of the liquid cntering the body il reaches a predetermined temperature.

It will be appreciated that although it is preferred to use the type of thermosensitive element described because it provides large force and movement, nevertheless is can be replaced by other forms of linearly-expanding thermosensitive element without departing from the spirit of the invention.

We claim:

l. A thermally controlled valve comprising, in combination, a housing having a bore therein extending transversely to the direction of ow through said housing, said housing having at least two angularly spaced ports in the wall of the bore, a rotor member rotatably mounted in said bore and having at least one shutter member thereon contro-lling at least one of said ports, said rotor member being movable from a position in which said at least one of said ports is obscured, a linearly expanding therrnosensitive actuator of the type having an actuator member which commences movement at a predetermined temperature mounted axially of said rotor member, a sleeve member mounted axially of the bore in said housing, said sleeve having a helical cam groove therein, a earn follower member on said actuator member engaging said cam groove, and means on said housing for adjusting the longitudinal position of said sleeve member relative to said housing, whereby the position of the rotor may be adjusted to correspond to a given temperature.

2. A thermally controlled valve comprising, in combination, a housing having a cylindrical bore therein, said housing having three angularly spaced ports in the wall of the bore, a rotor member rotatably mounted in said bore and having shutter members thereon controlling two of said ports, said rotor member being movable from a position in which one of said two ports is obscured through intermediate positions in which both of said two ports are partially obscured to a position in which the other of said two ports are obscured, a linearly expanding thermosensitive actuator of the type having an actuator member which commences movement at a predetermined temperature mounted axially of said rotor member, a sleeve member mounted axially of the bore in said housing, said sleeve having a helical cam groove therein, a cam follower member on said actuator member engaging said cam groove, and means on said housing for adjusting the longitudinal position of said sleeve member relative to said housing, whereby the position of the rotor may be adjusted to correspond to a given temperature.

3. A. thermally controlled valve according to claim 2, wherein the cam groove is provided with straight portions at least at one end, the said portion extending parallel with the axis of the sleeve, the sleeve being adjustable longitudinally by an amount suiiicient to bring the cam follower within said straight portion throughout the operating range of the valve.

4. A thermally controlled valve according to claim 3, wherein means for moving the sleeve relative to said housing is a spring, a catch for holding said spring in a References Cited in the le of this patent UNITED STATES PATENTS Modine Dec. 1, 1931 Gaul Jan. 2, 1940 Orem May 7, 1940 June 14, 1949

Images