VALVE REPSONSIVE TO TEMPERATURE CHANGES OVER A LIMITED RANGE
United States Patent 3696997
A fluid flow metering valve which varies effective flow area in response to temperature changes over a limited temperature range. The valve core, having a conically shaped end positioned in the fluid flow port, expands freely as temperature increases to a predetermined value from a temperature below that value. Thereafter, an abutment in the valve casing is engaged by a shoulder on the valve core to prevent the conically shaped end of the core from advancing further into the port, with additional expansion of the core being accommodated at the opposite end of the casing. A spring retains the core in the casing and returns it to its original position upon a decrease in temperature to and below the predetermined value.
US Patent References:
Temperature compensated metering valve
Raulins - December 1960 - 2966170
Thermostatic snap-action valve device
Meyer et al. - December 1961 - 3014664
Temperature regulated flow control valve
Getz - May 1967 - 3322345
Temperature compensated metering valve
Raulins - December 1960 - 2966170
Thermostatic snap-action valve device
Meyer et al. - December 1961 - 3014664
Temperature regulated flow control valve
Getz - May 1967 - 3322345
Application Number:
05/132666
Publication Date:
10/10/1972
Filing Date:
04/09/1971
View Patent Images:
Export Citation:
Assignee:
Vernay Laboratories, Inc. (Yellow Springs, OH)
Primary Class:
Other Classes:
261/DIG.038, 261/71, 261/39.100, 261/41.500
International Classes:
G05D23/02; G05D23/01; G05D23/275
Field of Search:
236/102,101,93,87
Primary Examiner:
Michael, Edward J.
Claims:
What is claimed is
1. A thermally responsive valve comprising:
2. The valve of claim 1 wherein:
3. The valve of claim 2 wherein:
4. The valve of claim 3 further comprising:
5. The valve of claim 1 wherein:
6. The valve of claim 5 wherein:
7. The valve of claim 6 further comprising:
8. A thermally responsive valve comprising:
9. The valve of claim 8 further comprising:
10. The valve of claim 8 further comprising:
11. The valve of claim 4 wherein:
12. The valve of claim 7 wherein:
13. The valve of claim 10 wherein:
14. The valve of claim 13 wherein:
1. A thermally responsive valve comprising:
2. The valve of claim 1 wherein:
3. The valve of claim 2 wherein:
4. The valve of claim 3 further comprising:
5. The valve of claim 1 wherein:
6. The valve of claim 5 wherein:
7. The valve of claim 6 further comprising:
8. A thermally responsive valve comprising:
9. The valve of claim 8 further comprising:
10. The valve of claim 8 further comprising:
11. The valve of claim 4 wherein:
12. The valve of claim 7 wherein:
13. The valve of claim 10 wherein:
14. The valve of claim 13 wherein:
Description:
CROSS REFERENCE TO RELATED APPLICATION
THERMALLY RESPONSIVE VALVE ASSEMBLY, by Robert T. Gifford, Ser. No. 132,494, filed Apr. 8, 1971.
BACKGROUND OF THE INVENTION
In the above noted, related application a valve assembly is disclosed in which a unitary, rod-like valve member is received in a valve casing with one end of the valve member attached to the casing and the opposite end projecting outwardly thereof into a fluid flow port. The diameter of the valve member is sufficiently smaller than the internal bore of the valve casing to permit the main body of the valve member to move within the casing and the materials of which the casing and valve member are constructed are selected such that the coefficient of linear thermal expansion of the valve member is appreciably greater than that of the casing.
The free end of the valve member projects outwardly of the casing so that when the casing is attached to the wall of a member having a flow port therein through which the fluid flow is to be regulated, the outwardly projecting end of the valve member is positioned in the fluid flow port. With this construction an increase in temperature will cause the valve member to expand and advance its outwardly projecting end farther into the fluid flow port. This results in a decrease in the effective flow area through the port. A decrease in temperature of course, will result in an increase in effective flow area as the valve member contracts and in this way the flow of fluid through the port is regulated in response to temperature changes.
While the above described construction functions effectively in its intended environment, it will be seen that the effective flow area through the flow port will be continuously decreased in response to increases in temperature. In certain installations, however, it is desirable to set a lower limit for effective flow area regardless of further temperature increases. In the idling inlet port of a carburetor, for example, while it is desirable to decrease the effective flow area of the port in response to increases in temperature, there is a certain minimum effective open area which must be maintained regardless of continued temperature increases. Obviously, in a valve construction in which movement of the valve member is unrestrained temperatures may be encountered which are high enough to close the effective flow area below the minimum desired or even close it completely.
SUMMARY OF THE INVENTION
The present invention provides a valve assembly which is responsive to temperature changes over a limited range of values. Thus, as the temperature rises above a first value, which is below some preselected temperature, the valve member will expand, advancing its flow regulating end farther into the flow port with which it is associated, thereby reducing the effective area of the flow port. However, after the valve member has expanded a certain predetermined amount, at which point the valve member will be at the preselected temperature, an outwardly projecting shoulder on the valve member engages an inwardly projecting shoulder on the casing within which it is mounted to prevent further advance of the conically shaped end of the valve member in any appreciable amount.
A further increase in temperature above the preselected temperature, and thus, further expansion of the valve member, is accommodated at the opposite end of the casing, where the opposite end of the valve member advances in opposition to the pressure of a spring mounted in the casing at that point. As a result, after the temperature has reached some predetermined value and the effective open area of the flow port has been reduced to a predetermined amount, the effective area of the flow port remains relatively constant regardless of continued temperature increases.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view, partly in section, showing the valve assembly with the valve core thereof in a first position;
FIG. 2 is a view similar to FIG. 1, but showing the valve core in a second position thereof; and
FIG. 3 is a graph comparing the travel of the valve member of the present invention in response to temperature change to the travel of a valve member in which movement thereof is unrestrained.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference initially to FIG. 1 of the drawings, it will be seen that a valve assembly in accordance with the present invention includes a valve casing 10 having an internal bore 11 and an externally threaded portion 12 extending from adjacent one end 14 thereof to an enlarged opposite end 16. At the end 14 of the casing a shoulder projects radially inwardly into the bore 11 to define an abutment 18 at that point. At its enlarged end 16 a shoulder or stop member 22 is defined by a portion projecting outwardly of the bore 11.
Received within the casing 10 is an elongated, unitary, rod-like valve member or core 24 having a conically shaped, fluid flow regulating end 26. The valve core 24 is also provided with an outwardly projecting shoulder 28 positioned in opposition to the inwardly projecting abutment 18 of the valve casing. The opposite end of the valve core 24 is provided with an enlarged head portion 30 to provide an outwardly projecting shoulder 32 positioned in opposition to the shoulder 22 of the casing 10.
A retainer 34 is force fitted into the enlarged open end of the casing 16 and serves to retain a spring member 36 mounted in a pocket 38 in the end of the valve member or core 24. The valve assembly thus described may be readily fixed within a threaded opening of a member 40 with which it is associated by means of the external threads 12 thereof engaging complementary threads 42 formed in the wall of the member 40.
Thus, the casing 10 is threaded into the portion 42 of the member 40 to obtain the desired clearance between the conically shaped end 26 of the valve core 24 and the flow port 44 at a preselected temperature. A coil spring 46 encircles the outwardly projecting portion of the casing 10 and bears against the member 40 at one end and the enlarged head 16 of the casing at its opposite end and serves to retain the casing in this preset position. It will also be noted that the enlarged head 16 of the casing 10 may be provided with a tool engaging portion, such as the slot 48, to facilitate adjustment of the casing within the threaded portion of the member 40.
In operation, assume that the temperature is below the preselected temperature such that the position of the core 24 within the casing 10 is as shown in FIG. 1 of the drawings. Fluid flow may be in the direction indicated by the arrows in FIGS. 1 and 2 although it will be apparent that the flow direction could be reversed. In this position it will be noted that the outwardly projecting shoulder 28 is spaced from the abutment 18 formed by the inwardly projecting portion of the casing 10 and that the under surface of the enlarged head 30 of the core 24 is seated against the outwardly projecting shoulder 22 of the casing 10 and held in this position by means of the spring 36.
If the temperature thereafter increases, the core 24 will expand, causing its conically shaped end 26 to advance farther into the flow port 44. This advance will continue as the temperature increases further until the shoulder 28 engages the abutment 18 at the preselected temperature, with additional advancement being negligible since it is caused only by the expansion of the relatively short section of the core extending from adjacent the outwardly projecting shoulder 28. Continued increase in temperature and commensurate expansion of the core 24 will be accommodated in the enlarged end 16 of the casing by movement of the head 30 in opposition to the spring member 36.
This, as seen in FIG. 2, will cause the under surface 32 of the head 30 to move from engagement with the outwardly projecting shoulder 22, compressing the spring 36. Of course, as the temperature thereafter decreases, the spring 36 will first urge the shoulder 32 into engagement with the stop 22 and further contraction of the core 24 will cause the shoulder 28 to become disengaged from the abutment 18, retracting the conically shaped end 26 of the core 24 from the flow port 44 and thereby increasing the effective flow area therethrough.
With reference to FIG. 3 of the drawings it will be noted that the travel of the conically shaped end of the core 24 in response to changes in temperature is essentially the same as that of a valve assembly of the type described in the above noted related application until some predetermined advancement of the core 26, as indicated by the letter A on the curve, is reached. Thereafter, continued increase in temperature will result in only negligible travel of the end 26 of the core, as indicated by that portion of the curve labelled B, as contrasted to the continued travel of a corresponding portion of a core in which movement thereof is unrestrained, as indicated by the portion of the curve labelled C in FIG. 3 of the drawings.
Of course, it is necessary to dimension the length of the core 24 with respect to the length of the bore of the casing 10 as well as properly select materials for the core and the casing having coefficients of linear thermal expansion to give the desired results. In this regard it has been found that the valve casing may be formed of a material such as steel having a coefficient of linear thermal expansion of approximately 6 × 10 - 6 inch/inch/°F., although a 20-40 percent glass filled, relatively rigid, organic polymer, such as nylon, will also function satisfactorily.
The material of which the core is formed must have an appreciably higher coefficient of linear thermal expansion and desirably is at least three times greater than the thermal coefficient of expansion of the valve casing. In constructing the valve core various relatively rigid, organic polymers, such as nylon, polyethylene, acetal resins, acrylics and polyvinylidene fluoride, have been found satisfactory. Thus, using steel as the casing material and forming the core of polyvinylidene fluoride, the coefficient of linear thermal expansion of the core will be approximately thirteen times greater that that of the casing or shell.
Obviously, however, a wide variety of materials may be utilized in practicing the present invention and with various combinations of readily available materials the range of differences in coefficients of linear thermal expansion will range from about 3 to 25. The only requirements are that the coefficients of linear thermal expansion of the core and the casing are sufficiently different to give appreciable core travel and that the length of the core relative to the length of the internal bore of the casing is such as to permit appreciable travel of the core only within certain predetermined limits.
While the forms of apparatus herein described constitutes preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.
THERMALLY RESPONSIVE VALVE ASSEMBLY, by Robert T. Gifford, Ser. No. 132,494, filed Apr. 8, 1971.
BACKGROUND OF THE INVENTION
In the above noted, related application a valve assembly is disclosed in which a unitary, rod-like valve member is received in a valve casing with one end of the valve member attached to the casing and the opposite end projecting outwardly thereof into a fluid flow port. The diameter of the valve member is sufficiently smaller than the internal bore of the valve casing to permit the main body of the valve member to move within the casing and the materials of which the casing and valve member are constructed are selected such that the coefficient of linear thermal expansion of the valve member is appreciably greater than that of the casing.
The free end of the valve member projects outwardly of the casing so that when the casing is attached to the wall of a member having a flow port therein through which the fluid flow is to be regulated, the outwardly projecting end of the valve member is positioned in the fluid flow port. With this construction an increase in temperature will cause the valve member to expand and advance its outwardly projecting end farther into the fluid flow port. This results in a decrease in the effective flow area through the port. A decrease in temperature of course, will result in an increase in effective flow area as the valve member contracts and in this way the flow of fluid through the port is regulated in response to temperature changes.
While the above described construction functions effectively in its intended environment, it will be seen that the effective flow area through the flow port will be continuously decreased in response to increases in temperature. In certain installations, however, it is desirable to set a lower limit for effective flow area regardless of further temperature increases. In the idling inlet port of a carburetor, for example, while it is desirable to decrease the effective flow area of the port in response to increases in temperature, there is a certain minimum effective open area which must be maintained regardless of continued temperature increases. Obviously, in a valve construction in which movement of the valve member is unrestrained temperatures may be encountered which are high enough to close the effective flow area below the minimum desired or even close it completely.
SUMMARY OF THE INVENTION
The present invention provides a valve assembly which is responsive to temperature changes over a limited range of values. Thus, as the temperature rises above a first value, which is below some preselected temperature, the valve member will expand, advancing its flow regulating end farther into the flow port with which it is associated, thereby reducing the effective area of the flow port. However, after the valve member has expanded a certain predetermined amount, at which point the valve member will be at the preselected temperature, an outwardly projecting shoulder on the valve member engages an inwardly projecting shoulder on the casing within which it is mounted to prevent further advance of the conically shaped end of the valve member in any appreciable amount.
A further increase in temperature above the preselected temperature, and thus, further expansion of the valve member, is accommodated at the opposite end of the casing, where the opposite end of the valve member advances in opposition to the pressure of a spring mounted in the casing at that point. As a result, after the temperature has reached some predetermined value and the effective open area of the flow port has been reduced to a predetermined amount, the effective area of the flow port remains relatively constant regardless of continued temperature increases.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view, partly in section, showing the valve assembly with the valve core thereof in a first position;
FIG. 2 is a view similar to FIG. 1, but showing the valve core in a second position thereof; and
FIG. 3 is a graph comparing the travel of the valve member of the present invention in response to temperature change to the travel of a valve member in which movement thereof is unrestrained.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference initially to FIG. 1 of the drawings, it will be seen that a valve assembly in accordance with the present invention includes a valve casing 10 having an internal bore 11 and an externally threaded portion 12 extending from adjacent one end 14 thereof to an enlarged opposite end 16. At the end 14 of the casing a shoulder projects radially inwardly into the bore 11 to define an abutment 18 at that point. At its enlarged end 16 a shoulder or stop member 22 is defined by a portion projecting outwardly of the bore 11.
Received within the casing 10 is an elongated, unitary, rod-like valve member or core 24 having a conically shaped, fluid flow regulating end 26. The valve core 24 is also provided with an outwardly projecting shoulder 28 positioned in opposition to the inwardly projecting abutment 18 of the valve casing. The opposite end of the valve core 24 is provided with an enlarged head portion 30 to provide an outwardly projecting shoulder 32 positioned in opposition to the shoulder 22 of the casing 10.
A retainer 34 is force fitted into the enlarged open end of the casing 16 and serves to retain a spring member 36 mounted in a pocket 38 in the end of the valve member or core 24. The valve assembly thus described may be readily fixed within a threaded opening of a member 40 with which it is associated by means of the external threads 12 thereof engaging complementary threads 42 formed in the wall of the member 40.
Thus, the casing 10 is threaded into the portion 42 of the member 40 to obtain the desired clearance between the conically shaped end 26 of the valve core 24 and the flow port 44 at a preselected temperature. A coil spring 46 encircles the outwardly projecting portion of the casing 10 and bears against the member 40 at one end and the enlarged head 16 of the casing at its opposite end and serves to retain the casing in this preset position. It will also be noted that the enlarged head 16 of the casing 10 may be provided with a tool engaging portion, such as the slot 48, to facilitate adjustment of the casing within the threaded portion of the member 40.
In operation, assume that the temperature is below the preselected temperature such that the position of the core 24 within the casing 10 is as shown in FIG. 1 of the drawings. Fluid flow may be in the direction indicated by the arrows in FIGS. 1 and 2 although it will be apparent that the flow direction could be reversed. In this position it will be noted that the outwardly projecting shoulder 28 is spaced from the abutment 18 formed by the inwardly projecting portion of the casing 10 and that the under surface of the enlarged head 30 of the core 24 is seated against the outwardly projecting shoulder 22 of the casing 10 and held in this position by means of the spring 36.
If the temperature thereafter increases, the core 24 will expand, causing its conically shaped end 26 to advance farther into the flow port 44. This advance will continue as the temperature increases further until the shoulder 28 engages the abutment 18 at the preselected temperature, with additional advancement being negligible since it is caused only by the expansion of the relatively short section of the core extending from adjacent the outwardly projecting shoulder 28. Continued increase in temperature and commensurate expansion of the core 24 will be accommodated in the enlarged end 16 of the casing by movement of the head 30 in opposition to the spring member 36.
This, as seen in FIG. 2, will cause the under surface 32 of the head 30 to move from engagement with the outwardly projecting shoulder 22, compressing the spring 36. Of course, as the temperature thereafter decreases, the spring 36 will first urge the shoulder 32 into engagement with the stop 22 and further contraction of the core 24 will cause the shoulder 28 to become disengaged from the abutment 18, retracting the conically shaped end 26 of the core 24 from the flow port 44 and thereby increasing the effective flow area therethrough.
With reference to FIG. 3 of the drawings it will be noted that the travel of the conically shaped end of the core 24 in response to changes in temperature is essentially the same as that of a valve assembly of the type described in the above noted related application until some predetermined advancement of the core 26, as indicated by the letter A on the curve, is reached. Thereafter, continued increase in temperature will result in only negligible travel of the end 26 of the core, as indicated by that portion of the curve labelled B, as contrasted to the continued travel of a corresponding portion of a core in which movement thereof is unrestrained, as indicated by the portion of the curve labelled C in FIG. 3 of the drawings.
Of course, it is necessary to dimension the length of the core 24 with respect to the length of the bore of the casing 10 as well as properly select materials for the core and the casing having coefficients of linear thermal expansion to give the desired results. In this regard it has been found that the valve casing may be formed of a material such as steel having a coefficient of linear thermal expansion of approximately 6 × 10 - 6 inch/inch/°F., although a 20-40 percent glass filled, relatively rigid, organic polymer, such as nylon, will also function satisfactorily.
The material of which the core is formed must have an appreciably higher coefficient of linear thermal expansion and desirably is at least three times greater than the thermal coefficient of expansion of the valve casing. In constructing the valve core various relatively rigid, organic polymers, such as nylon, polyethylene, acetal resins, acrylics and polyvinylidene fluoride, have been found satisfactory. Thus, using steel as the casing material and forming the core of polyvinylidene fluoride, the coefficient of linear thermal expansion of the core will be approximately thirteen times greater that that of the casing or shell.
Obviously, however, a wide variety of materials may be utilized in practicing the present invention and with various combinations of readily available materials the range of differences in coefficients of linear thermal expansion will range from about 3 to 25. The only requirements are that the coefficients of linear thermal expansion of the core and the casing are sufficiently different to give appreciable core travel and that the length of the core relative to the length of the internal bore of the casing is such as to permit appreciable travel of the core only within certain predetermined limits.
While the forms of apparatus herein described constitutes preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.