Electronic thermometer and method

• US 4,008,617 A
• Filed: 12/08/1975
• Issued: 02/22/1977
• Est. Priority Date: 01/09/1975
• Status: Expired due to Term

• Current Assignee: Filac Corporation
• Original Assignee: Filac Corporation
• Inventors: Lee, John J., Yen, David H., Connely, Tim R.
• Primary Examiner(s): Myracle, Jerry W.
• Application Number:
  US05/638,430
• Time in Patent Office: 442 Days
• Field of Search: 73/362 AR, 73/362 R
• US Class Current: 374/169
• CPC Class Codes: G01K 3/00 Thermometers giving results other than momentary value of temperature G01K7/42 takes precedence

Abstract

Electronic thermometer and method for determining temperature in which compensation is provided for the localized cooling of a body caused by bringing a sensing element of lower temperature into contact with the body. The output of the sensing element is combined with a signal representative of the initial temperature of the element to compensate for the localized cooling and provide an advance indication of the equilibrium temperature of the body.

Claims

1. In a method of determining the temperature of a body utilizing a sensing element having an initial temperature different than the temperature of the body, the steps of:

bringing the sensing element into contact with a predetermined region of the body, the temperature of said region being changed by the contact with the sensing element, maintaining the sensing element in contact with the body to permit the temperature of the sensing element and the temperature of the predetermined region to approach equilibrium with the temperature of the remainder of the body, providing an electrical signal corresponding to the temperature of the sensing element, storing a signal corresponding to the initial temperature of the sensing element, and combining the stored signal with the temperature signal a predetermined time after the sensing element is brought into contact with the body to provide an advance indication of the equilibrium temperature.

2. The method of claim 1 wherein the temperature signal is combined with the stored signal according to the following relationship:

space="preserve" listing-type="equation">T.sub.OUT = T.sub.PROBE + K1 (K2 - T.sub.INIT) + K3,

where T_OUT is the advance indication of the equilibrium temperature, T_PROBE is the temperature of the sensing element at the end of a predetermined measurement period, T_INIT is the initial temperature of the sensing element, K1 is the change in T_PROBE per unit change in T_INIT, K2 is a predetermined value of T_INIT, and K3 is the difference between the equilibrium temperature and T_PROBE when T_INIT = K2.

3. In an electronic thermometer for determining the temperature of a body:

a sensing element contactable with the body and having an initial temperature lower than the temperature of the body, means connected to the sensing element for providing an electrical signal corresponding to the temperature of the element, means for storing an electrical signal corresponding to the initial temperature of the sensing element, and means responsive to the stored signal and the temperature signal a predetermined time after the sensing element is contacted with body for providing an advance indication of the equilibrium temperature of the sensing element and body.

4. The thermometer of claim 3 wherein the means responsive to the stored signal and the temperature signal includes means for combining said signals according to the following relationship:

space="preserve" listing-type="equation">T.sub.OUT = T.sub.PROBE + K1 (K2 - T.sub.INIT) + K3,

where T_OUT is the advance indication of the equilibrium temperature, T_PROBE is the temperature of the sensing element at the predetermined time, T_INIT is the initial temperature of the sensing element, K1 is the change in T_PROBE per unit change in T_INIT, K2 is a predetermined value of T_INIT, and K3 is the difference between the equilibrium temperature and T_PROBE when T_INIT = K2.

5. In an electronic thermometer:

a sensing element adapted to be brought into contact with a body for determining the temperature of the body, means connected to the sensing element for providing an electrical signal corresponding to the temperature of said element, means for storing a signal corresponding to the temperature of the sensing element prior to contact with the body, means responsive to the electrical signal for detecting contact between the sensing element and the body, summation means for combining the electrical signal and the stored signal in a predetermined manner to provide an output signal indicative of the temperature of the body, and means for delivering the output signal to a temperature indicator a predetermined time after contact between the sensing element and body is detected, said predetermined time being shorter than the time required for the temperature of the sensing element and body to reach equilibrium.

6. The thermometer of claim 5 wherein the means for storing a signal comprises a digital counter and means for advancing the counter to a level corresponding to the temperature of the sensing element prior to contact with the body.

7. The thermometer of claim 5 wherein the means for detecting contact comprises a level detector responsive to a predetermined level of the electrical signal.

8. The thermometer of claim 5 wherein the means for detecting contact comprises a slope detector responsive to a predetermined rate of change in the electrical signal.

9. The thermometer of claim 5 wherein the electrical signal and the stored signal are combined according to the following relationship:

space="preserve" listing-type="equation">T.sub.OUT = T.sub.PROBE + K1 (K2 - T.sub.INIT) + K3,

where T_OUT is the output signal, T_PROBE is the advance indication of the equilibrium temperature, T_PROBE is the temperature of the sensing element at the predetermined time, T_INIT is the initial temperature of the sensing element, K1 is the change in T_PROBE per unit change in T_INIT, K2 is a predetermined value of T_INIT, and K3 is the difference between the equilibrium temperature and T_PROBE when T_INIT = K2.