Abstract: An arrangement is disclosed wherein a luminosity detector and a pressure transducer are used in an internal combustion engine to determine the burned gas temperature and trapped mass within each combustion chamber of the engine on a cycle-to-cycle basis or over a period of cycles, and to predict NO.sub.x emissions from the engine. Also disclosed is an arrangement wherein the burned gas temperature in each combustion chamber can be determined using only the luminosity detector.

Abstract: A refrigerant storage container includes a temperature indicator to indicate the temperature of fluid in the container, a pressure gauge for indicating the pressure of the contained fluid and a temperature indexed vapor pressure scale on the face of the gauge. Another embodiment includes a thermal strip on the outside wall of the container which indicates a target pressure for a pure refrigerant contained therein. A third embodiment includes a temperature indicator, pressure gauge and a temperature pressure chart on an exterior wall of the container.

Abstract: An immersion well assembly for a fluid vessel, such as a boiler, hot water heater or piping system, having an existing threaded opening. A preexisting well housing a mechanical temperature sensor, which is connected to a temperature display or control first system, is removed from the opening, and the present assembly threaded therein. In this assembly are a (replacement) mechanical sensor to be connected to the first system and an electronic sensor. The electronic sensor is positioned in a small distal pocket and the sensor wires travel along a groove adjacent the mechanical sensor and out to a second system, such as a remote computer control system.

Abstract: A can testing device for measuring pressure and temperature in a sealed container wherein a strap encircles the body of the container circumferentially and a probe affixed to the strap penetrates the sidewall of the container to allow instruments for measuring the temperature and pressure of the container contents to come into physical contact with said contents.

Abstract: A monolithic pressure and/or temperature transducer comprises at least two sensitive semiconductor layers of III-V material sensitive to pressure and to temperature and supported by a common substrate of III-V material, which two layers comprise: a first layer doped with donor type impurities at a first concentration and having a first resistivity as a function of pressure and of temperature; and a second layer doped with donor type impurities at a second concentration different from the first concentration and having a second resistivity as a function of pressure and of temperature, which second resistivity depends on temperature in a different manner than the first resistivity.

Abstract: Methods and compositions for measuring the pressure of an oxygen-containing gas on an aerodynamic surface, by oxygen-quenching of luminescence of molecular sensors is disclosed. Objects are coated with luminescent films containing a first sensor and at least one of two additional sensors, each of the sensors having luminescences that have different dependencies on temperature and oxygen pressure. Methods and compositions are also provided for improving pressure measurements (qualitative or quantitive) on surfaces coated with a film having one or more types of sensor.

Abstract: A fluid temperature measuring device (10) comprises a substrate (12) upon which is deposited a first insulating layer (14). A first metallic layer (16) is sputtered onto the first insulating layer (14), a second insulating layer (18) is deposited on the first metallic layer (16) and a second metallic layer (20) is sputtered onto the second insulating layer (18).The second metallic layer (20) is thin and has a low heat capacity so that it responds quickly to changes in temperature of the fluid. The first metallic layer (16) is thin and is heated by supplying an electric current from an electrical power supply (22) to maintain the first metallic layer (16) at the same temperature as the second metallic layer (20).The second metallic layer (20) is electrically connected to an electrical resistance measuring device (24) which detects temperature changes of the fluid by detecting corresponding changes of the electrical resistance of the second metallic layer (20).

Abstract: A system is provided for measuring both the temperature and pressure of fluid in a borehole utilizing a single small diameter tube extending from the surface to the desired downhole test location in a borehole. Downhole fluid pressure is transmitted through the small diameter tube, while a sheathed thermocouple or fibre optic line extending along the flow path of the tube is used for transmitting downhole fluid temperature information to the surface. A continuous surface read-out of both pressure and temperature is thus possible, and the temperature read-out may be used to both monitor downhole fluid temperature and increase the accuracy of the fluid pressure measurement system.

Abstract: A device for measuring or controlling a property of a flow medium comprises a conduit which carries a flow medium. A choke element located in the conduit has a first open operating position and a second closed operating position. A driver drives the choke element from one operating position to the other. A pressure sensor measures the difference in pressure before and after the choke element in said conduit. A processor responsive to the pressure difference calculates a flow or thermal property of the flow medium. The processor comprises an input for receiving a continuous control signal which indicates a desired value of a flow or thermal property of the flow medium and a converter for converting the continuous control signal into a pulse-pause signal for controlling the driver.

Abstract: There is provided an apparatus for measuring variations in pressure including a container for housing a volume of liquid and an indicator float to be movably supported by the liquid therein. The float is to have a hollow interior portion for maintaining a volume of compressible fluid, and is vertically movable within the container. The apparatus further includes a variable buoyancy equilibrium force device for automatically offsetting buoyant forces created by the compressible fluid within the float, whereby the equilibrium force is automatically varied in response to changing buoyancy of the float corresponding to changing ambient pressures. In a preferred embodiment, the variable buoyancy equilibrium force device comprises a flexible ballast structure attached to an adjustable support above the float, and wherein excess length of the ballast collects in a ballast retainer on the upper portion of the float.

Abstract: A circuit arrangement is suggested for monitoring the air volume in vehicle tires which effects the most accurate possible correction of the temperature measured by a sensor fastened at the wheel to the actual air temperature in the tire. For this purpose, the temperature and pressure measurement value of the tire measured by the rotating sensor (13) of the wheel to be monitored is fed to a correction circuit (18) which is also receives a plurality of correction parameters (p, F, K, v). A corrected value for the temperature (t.sub.k) or for the air pressure in the tire is transmitted at the output of the correction circuit (18) as a function of the correction parameters (FIG. 1).

Abstract: A probe has an inlet and outlet by which a fluid flows over an optical sensing element in the sensing probe. Broad band optical radiation is supplied to the element and radiation transmitted through the optical sensing element is supplied to three photodiodes responsive respectively to radiation at different wavelengths. The transmission characteristic of the optical sensing element varies in different ways with change in temperature and pressure respectively. A store of temperature and pressure against amplitude of radiation at different wavelengths is addressed by the outputs of the photodiodes to give an indication of pressure and temperature at the sensing element.

Abstract: The differential pressure measuring apparatus comprises a single chamber differential pressure sensor filled with a fluid and having two measuring capacitors whose capacitances vary in opposite senses in response to the differential pressure to be measured and in the same sense in response to the temperature said capacitances being transformed by means of associated capacitance measuring circuits into measurement signals which are supplied to a calculation circuit for calculating the temperature and the differential pressure. A temperature measuring means which comprises a temperature sensor mounted on the differential pressure sensor and a temperature measuring circuit connected to the temperature sensor measures directly the temperature of the single chamber differential pressure sensor.

Abstract: A sensor for determining the pressure and temperature of the air in a vehicle tire and comprising temperature sensor elements decoupled from the temperature of the wheel rim and coupled to the temperature of the tire air. The temperature sensor elements are arranged on an insulating foil which is stretched over one of the openings of a cover cap which is fastened at the sensor housing so as to be thermally insulated. The temperature sensor elements are connected with connecting leads of the electronic circuit of the sensor via conductor paths of the insulating foil.

Abstract: A superheat sensor (10, 100) for sensing the superheat of a fluid (14) flowing through a fluid channel (16) in accordance with the invention includes an aperture (18) within the fluid channel; a sensor body (20) engaging the aperture with a fluid tight seal (26) between the body and the aperture, the sensor body having a sensor body channel (44) in fluid communication with fluid flowing within the fluid channel; a pressure sensor (22) contained within the sensor body having a pressure responsive element in fluid communication with the fluid flowing through the fluid channel for producing an electrical signal representative of pressure of fluid flowing in the fluid channel; a temperature sensor (52) connected to the sensor body having at least one surface in fluid communication with the fluid flowing through the fluid channel for producing an electrical signal representation of temperature of fluid flowing in the fluid channel contacting the at least one surface; and a superheat calculator (56), responsive to

Abstract: A sensor module supplying analog data signals from one of a temperature or pressure sensing element connects to a modular switch system through a D-shaped sensor port in the modular switch housing. The manufacturer and user may modify the standard modular switch system, which includes an internal electrical assembly to be a pressure or temperature switch by applying and removing selected sensor modules. The interconnection between the sensor module and the modular switch system includes particular leads carrying analog data signals and serial digital information signals. These leads are attached to a connector secured to the sensor module substrate. The connector is enclosed in a D-shaped extended portion of a cover which snap fits to an open end of the sensor module base. Mounted on the sensor module substrate are an amplifier, a reference voltage circuit and a non-volatile memory containing calibration data relating to the standardization of output signals from the sensors.

Abstract: In a method and an apparatus for testing a pneumatic tire such as for testing the uniformity thereof, a tire to be tested is inflated to a given pressure and rolled against a test surface at a tire contact patch, and forces and/or moments acting at the contact patch are measured. To at least reduce the period of time required for the tire to warm up for a testing operation, the compressed air used to inflate the tire is heated to a given temperature before being passed into the interior of the tire. The compressed air may be heated as it flows through a supply conduit, under the control of a sensor for sensing the temperature in the tire.

Abstract: An underwater frazil ice detector is disclosed comprising channel means disposed underwater for moving water therethrough, means for drawing water through said channel means, screen means disposed in and across said channel means so that water drawn therethrough by said water drawing means passes through said screen means, pressure detecting means disposed in said channel means and downstream of said screen means for detecting pressure differential across said screen means, whereby flow of water through said screen means is constricted when frazil ice forms thereon, creating an increased pressure differential across said screen means and thereby indicating the presence of frazil ice.

Abstract: An apparatus for measuring heat flow from a surface, including a heat flow measuring device for measuring heat flow from a surface; a structure for applying a relatively constant and repeatable force on the heat flow measuring device contacting the surface; an infrared pyrometer for measuring test surface temperature; an infrared pyrometer for measuring surrounding atmospheric temperature and a free standing support for supporting all of the above identified elements of the heat flow measuring device.

Abstract: Coding of the value of any number of quantities measured in a tire, for example its pressure and its temperature, is carried out using a ratio of time intervals TP/Tr, Tt/Tr. This frees the device from the effect of the time shift of the modulation system, the time shift affecting simultaneously the numerator and the denominator of said ratio.

Abstract: A nonintrusive flow sensing system (10) and related method are provided for monitoring fluid flow within a conduit (14), particularly such as a liquid flow (12). The sensing system (10) includes an array of ultrasonic transducers (18, 20, 24, 26) mounted on the conduit (14) and adapted to send and receive pulsed ultrasonic signals bidirectionally across the conduit with an upstream-downstream component of direction, and through the conduit in longitudinal and circumferential directions. Signal transit times are processed to obtain accurate measurements of liquid flow velocity, temperature and pressure.

Abstract: A kind of underground temperature and pressure measuring system for hot-exploiting oil well mainly comprises a casing, a high-temperature sealing element, a high-temperature time-controlling unit, a pressure sensing unit and its recording system and a temperature sensing unit and its recording system, wherein, the high-temperature sealing element is made of flexible graphite, and the pressure sensing element is made of particular material; the temperature sensing unit is connected with the pressure sensing unit by bellows, so that the temperature sensing unit and its recording system can be put around the pressure sensing unit and its recording system, and therefore the present device is not long, but it can be used to measure temperature and pressure of underground steam at different depth simultaneously, which make the calculation of underground thermal conditions possible and reliable.

Abstract: A single sensor is provided as part of a fiberoptic probe to measure up to three parameters, namely pressure (or force or displacement), temperature, and heat flow or fluid velocity. A solid elastomeric optical element is formed at the end of optical fiber transmission medium, and adjacent light reflective and temperature dependent materials are formed on the resulting convex surface of the optical element. The amount of light reflected is proportional to the force or pressure against the element. The temperature dependent material is preferably a luminescent material. Over the luminescent material is formed a layer of material that is absorptive of infrared radiation, thereby allowing a determination of characteristics of heat or fluid flow by measuring the rate at which heat is carried away from the infrared heated layer. The sensor can be formed at the end of a single optical fiber, thereby having extensive applications where a very small sensor is required.

Abstract: Multi-functional sensor comprises a support base made from borosilicate, a diaphragm with a E-shaped section secured to the base, the diaphragm being made from single crystalline silicon, principal plane thereof being oriented to be a crystalline plane (110), a differential pressure sensor having p-doped piezoresistor elements formed in the principal plane of the diaphragm at a thin wall portion of the E-shaped sectional diaphragm, each element being arranged along a crystal axis <111>, a static pressure sensor having p-doped piezoresistor elements formed in the principal plane at an outer peripheral thick wall portion of the E-shaped sectional diaphragm, each element being arranged along the crystal axis <111>, and a temperature sensor having a p-doped piezoresistor element formed in the principal plane at the outer peripheral thick wall portion of the E-shaped sectional diaphragm, the element being arranged along the crystal axis <100>.

Abstract: A temperature and pressure detecting type spark plug has a metallic shell having a mounting seat around an outer surface of the shell. The plug further has a center electrode which is placed into a tubular insulator.The center electrode has a hollow portion to enclose a thermocouple to detect a temperature of the front end of the center electrode.An annular pressure sensor is placed at the mounting seat of the metallic shell to detect a pressure within a combustion chamber in a cylinder head. The pressure sensor is arranged to be sandwiched between the mounting seat and the cylinder head when the spark plug is secured to the cylinder head of an internal combustion engine.

Abstract: A system and method of operation of a jet aircraft for a specific flight. The mass of liquid fuel in the aircraft's fuel tank is determined from the actual heating value of the fuel, based upon its density and temperature. The flight time available from the amount of fuel in the tank is determined and displayed. At least the amount of the fuel required for a specific flight is loaded into one or more fuel tanks on the aircraft.

Abstract: A sensor apparatus includes a pressure sensor, a reference device and a temperature sensor collocated within a common environment. The reference device and the temperature sensor are constructed to have temperature response times matched to the temperature response time of the pressure sensor to compensate for temperature gradients produced either by external heating or by pressure-volume heating.

Abstract: An apparatus for measuring heat flow from a surface, including a heat flow measuring device for measuring heat flow from a surface; a structure for applying a relatively constant and repeatable force on the heat flow measuring device contacting the surface; a free standing support for supporting the heat flow measuring device and the force applying structure, and an infrared pyrometer for measuring the temperature of the surface.

Abstract: In an improved semiconductor pressure sensor adapted to detect a pressure of a measured medium such as a refrigerant used in a refrigerating cycle for an automobile, there are provided a sensing portion composed of a glass support plate and a silicon substrate disposed thereon and provided with a diaphragm portion displaceable in accordance to a pressure of the measured medium at such a position of the silicon substrate as to be brought into contact with the measured medium, a detecting means disposed within the sensing portion so as to detect a displacement of the diaphragm portion, a housing having an interior space including an accommodation portion for accommodating the sensing portion and having at least a predetermined portion of the accommodation portion made up of metal as opposed to the sensing portion, and a solder glass provided between the predetermined portion of the housing and a predetermined portion of the sensing portion so as to hermetically seal the interior space of the housing with respec

Abstract: A circuit arrangement for transmitting variable measurement values, such as pressure and temperature, at vehicle wheels is provided which transmits the measurement values in the form of H-F signals to a stationary evaluating circuit (12) with great accuracy, high reliability and in short time intervals. A repeater coil (b 13), which is connected with the latter, arranged in the vicinity of the wheel so as to be stationary and connected to voltage by a square-wave generator (15), cooperates with a revolving repeated coil (19) which is fastened at the vehicle wheel and connected with a sensor circuit arrangement (20) supplied by it.

Abstract: In a method and apparatus for measuring temperature by using a state change of a working fluid, a temperature measurement is executed in a manner such that the working fluid is initially supplied at a constant mass flow rate into a flow channel having a throttle portion at a temperature-sensitive portion. Upon the measurement of a pressure difference between opposite ends of the throttle portion, the temperature can be determined through a calculation using the measured pressure difference. The temperature measuring apparatus includes a source of a working fluid and a probe. The probe includes an external cylinder closed at one of its ends and an internal cylinder which is accommodated in the external cylinder and has a capillary tube at its forward end. The apparatus further includes a supply tube for introducing the working fluid from the source into either the internal cylinder or the external cylinder, and a pressure control device.

Abstract: A modular switch device includes a housing enclosing an interconnected control module, a display module and a power module. A sensor module supplying analog data signals from one of a temperature or pressure sensing element connects to the control module through a passage in the housing. A user connects his electrical wires and electrical power to the electrical assembly within the housing through an opening. The user can select between AC and DC switched output modules and the presence or absence of a 4-20 milliampere output module by plugging and unplugging same from wells provided in the housing. The manufacturer and user thus can modify the standard housing, which includes an internal electrical assembly to be a pressure or temperature switch and to provide selected output switch characteristics by applying and removing selected sensor and output modules thereto.

Abstract: An apparatus for measuring heat flow from a surface, including a heat flow measuring device for measuring heat flow from a surface; a structure for applying a relatively constant and repeatable force on the heat flow measuring device contacting the surface; and a free standing support for supporting the heat flow measuring device and the force applying structure.

Abstract: An apparatus and method for measurement of the thermal conductivity of polymer melts is disclosed. A sample of material to be measured is placed in an elongated cylindrical container and is heated to a preselected base temperature. A probe placed in the container in contact with the sample contains a transient heating element and a temperature sensor. To determine the thermal conductivity of the sample material, the transient heating element is energized and the resulting changing temperature of the sample material is measured for a short period of time. The rate of temperature change is a measure of the thermal conductivity of the sample material at the base temperature.

Abstract: A transducer to measure pressure or temperature comprising a quantity of compressible material such as gas and a quantity of incompressible material such as liquid and proper means (16,17) to detect volume and interface(s) (14) changes of said compressible material induced by pressure or temperature variation. Radiation may be used to detect said changes. Both source (16) and detector (17) of radiation may be separated from said compressible and incompressible materials using appropriate waveguides (10,11) thus allowing for transducer miniaturization. The only deformable element of the transducer is said compressible material, every other part of it being substantially rigid this feature offering robustness and simplicity of construction. Provision is made for the in-situ calibration and flushing of the instrument when required.

Abstract: A system for detecting a nuclear weapon explosion and assessing damage therefrom comprising a sensor head and an electronic signal processor is disclosed. The sensor head is spherical in shape and comprises a plurality of temperature sensors at different locations on the sensor head and provide information concerning the direction of the radiation. Elapsed time between thermal pulse peaks measure yield of the weapon. A plurality of pressure sensors embedded in the sensor head measure blast overpressure. The time lapse between the temperature and pressure signals measures distance. Gamma and neutron sensors indicate the type of weapon and radiation hazard. The electronic signal processor provides the necessary calculations.

Abstract: Air data measurement apparatus for use on an aircraft, comprises a housing (1) open at both ends (2, 3) and divided into two chambers (8, 9) by a transverse wall (7). The leading end chamber (8) contains a total pressure sensor (11) and the trailing end chamber (9) contains a total temperature sensor assembly (15) whereby the apparatus functions to measure total temperature and pressure at a common point on an aircraft.

Abstract: A sensor apparatus includes a pressure sensor, a reference device and a temperature sensor collocated within a common environment. The reference device and the temperature sensor are constructed to have temperature response times matched to the temperature response time of the pressure sensor to compensate for temperature gradients produced either by external heating or by pressure-volume heating.

Abstract: A probe housing includes a cover and an aluminum base that comprises a plate and a threaded collar for screwing the base onto a pipe-T. A threaded bore permits liquid from the pipe-T to pass through the plate. A pressure transducer, comprises a transducer housing and a threaded coupling. The transducer, a circuit board, and a washer-shaped circuit board support are mounted in the probe housing with the threaded coupling passing through a hole in the circuit board and the circuit board support and screwing into the bore in the base plate so that the circuit board is firmly held between the transducer housing and the support. A temperature sensor is held in a cavity in the plate by thermally conductive adhesive and is separated from the liquid in the pipe-T by only a relatively thin portion of the base to sense the temperature of the liquid.

Abstract: A probe suitable for monitoring temperature and pressure in a relatively thin-walled container fabricated from plastic. The internal probe monitors the pressure and temperature at substantially the geometric center of a container in a pasteurizing or sterilizing apparatus. The probe is provided with a sharp container-wall piercing end and a tapered threaded self tapping portion which provides an effective seal. The probe is hollow so that fluid can be conducted from the interior of the container and its pressure determined. A temperature sensing member is carried within the hollow probe so that temperature within the container may be sensed.

Abstract: A sensor for fluid systems for continuous detection of operating pressures and temperatures, with a sensor housing to receive a temperature probe and a pressure sensor. Simultaneous detection of pressures and temperatures is achieved by a sensor housing having a connecting nipple equipped with a bore. A temperature probe passes through the bore forming an annular flow channel which is fluidically connected to a pressure sensor chamber of a pressure sensor. The temperature probe is adjustable in an axial direction by an adjusting device.

Abstract: Method and apparatus are provided for simultaneously measuring temperature and pressure in a class of crystalline materials having anisotropic thermal coefficients and having a coefficient of linear compression along the crystalline c-axis substantially the same as those perpendicular thereto. Temperature is determined by monitoring the fluorescence half life of a probe of such crystalline material, e.g., ruby. Pressure is determined by monitoring at least one other fluorescent property of the probe that depends on pressure and/or temperature, e.g., absolute fluorescent intensity or frequency shifts of fluorescent emission lines.

Abstract: A portable test device for set point and leakage testing of a variety of sizes of pressure relief valves using the actual operating fluid under realistic test conditions includes a housing having a cylindrical bore, a main piston slidable in the bore to form at one end a test chamber, a translator piston also slidable in the bore to form at the other end a pressurizing chamber, and a spring pack biasing the pistons apart. An adapter plate mounts various size relief valves to the device with the valve inlet in communication with the test chamber. With a fixed amount of test fluid sealed in the test chamber, the pressure of hydraulic fluid introduced into the pressurizing chamber increases the pressure of the test fluid until the valve actuates. An electric immersion heater in the test chamber provides the capability for hot liquid testing and vapor testing.

Abstract: A pressure and temperature measuring probe with a low drag, airfoil shaped cross section includes a longitudinally extending pressure cavity adjacent the leading edge and a separate longitudinally extending temperature cavity immediately downstream thereof. Longitudinally spaced apart passages extend downstream from their inlets at pressure measuring stations along the leading edge and intersect the pressure cavity. At temperature measuring stations along the leading edge passages extend downstream adjacent the pressure cavity to intersect the temperature cavity and direct a high velocity flow of gases over a thermocouple junction disposed within the temperature cavity. Stagnation devices at the leading edge reduce gas velocity to zero at the passage inlets.

Abstract: Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction of vapor pressure changes.

Abstract: An apparatus is disclosed for monitoring the temperature of the propulsion gas at the inlet to a turbine wheel in a turbine in which a compressor fuels air into a chamber where it is heated and the heated products exiting the chamber form the propulsion gas. The temperature of the heated products exiting the chamber is a function of the inlet static and total pressure, the total inlet temperature, the static pressure of the heated products and the static pressure drop across the chamber.

Abstract: A conduction-responsive meter head has a device having electrical conduction responsive to a condition such as pressure to be metered. The device communicates with the condition to provide its electrical-conduction response to a bridge electrically including the device. A power supply has two terminals on the meter head for providing electrical power to the bridge. The measurement signal from the bridge is provided, however, to a third terminal by a lead from the bridge.

Abstract: A tire pressure monitor arranged on a conventional wheel with a visual display viewable from the exterior of the wheel when it is stationary. The display typically presents a numerical indication of tire pressure. The electronic components for the display are housed within an enclosure mounted to the disk of the wheel. An air duct leads through the rim of the wheel to the enclosure for sampling interior tire pressure.

Abstract: A coding circuit comprises an astable multivibrator which transforms the measurement of the variables in question, for instance pressure and temperature, into a time measurement. The astable multivibrator delivers a pulse signal whose pulse width is a function of the temperature and the cyclic ratio of which is a function of the pressure.

Abstract: A temperature-compensated Bourdon tube gauge for indicating a parameter of a pressurized fluid, including a support structure, a Bourdon tube having an open fixed end receiving the fluid and a free closed end carrying an indicating member, a dial member carrying a parameter scale disposed along the path of motion of the indicating member, and a temperature-responsive element for moving the dial member in accordance with a sensed temperature such that the indicating member indicates the fluid parameter on the dial member scale. The temperature-responsive element comprises a bimetallic element connected between the support structure and the dial member. The bimetallic element may be connected to the dial member by a lever having a "variable fulcrum" which varies along the length of the lever in accordance with the shape of a cam with which the lever is maintained in contact.