SOLIDIFICATION SENSOR

• US 20080121024A1
• Filed: 11/21/2007
• Published: 05/29/2008
• Est. Priority Date: 11/24/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohta, Hiroyuki, Tanno, Yohei, Shimazu, Hiromi, Saito, Naoto, Uchida, Mari
• Granted Patent: US 7,836,755 B2
• Time in Patent Office: Days
• US Class Current: 73/61.44
• CPC Class Codes: G01N 2203/0075 Strain-stress relations or elastic constants
• CPC Class Codes: G01N 2203/0092 Visco-elasticity, solidification, curing, cross-linking degree, vulcanisation or strength properties of semi-solid materials
• CPC Class Codes: G01N 25/02 by investigating changes of state or changes of phase; by investigating sintering investigating or analysing oils or hydrocarbon fluids by measuring cloud point or pour point G01N33/2811

Abstract

In a solidification sensor for measuring a solidification state of a liquid with a high degree of accuracy in real time, and for making the sensor small-sized with a reduced power consumption, the solidification sensor comprises a liquid absorbing portion formed of a liquid absorbable material, a substrate coupled to the liquid absorbing portion and a strain sensor for measuring strain exerted to the substrate due to a volumetric change upon solidification of a liquid absorbed in the liquid absorbing portion.

Claims

1. A solidification sensor comprising:

a liquid absorbing portion formed of a member capable of absorbing a liquid,

a substrate coupled to the liquid absorbing portion, and

a strain sensor for measuring a strain exerted to the substrate.

2. A solidification sensor as set forth in claim 1, wherein the substrate provided with said strain sensor is rectangular.

3. A solidification sensor as set forth in claim 1, wherein the liquid absorbing portion is coupled to both ends of the substrate on which the strain sensor is provided.

5. A solidification sensor as set forth in claim 1, wherein a length of the liquid absorbing portion is shorter than that of the substrate provided with the strain sensor.

6. A solidification sensor as set forth in claim 1, wherein the substrate has a strip-like shape, and the liquid absorbing portion is formed of a strip-like fabric coupled to both ends of said substrate.

7. A solidification sensor as set forth in claim 1, wherein the liquid absorbing portion is coupled to said substrate over one side surface of the latter in its entirety.

8. A solidification sensor as set forth in claim 1, wherein the substrate is made of metal material.

9. A solidification sensor as set forth in claim 1, wherein the strain sensor has a bridge which is formed of an impurity layer on a silicon substrate.

10. A solidification sensor as set forth in claim 1, wherein said strain sensor has four p-type impurity layers which are arranged in a direction of <

110>

.

11. A solidification sensor as set forth in claim 1, wherein said strain sensor has four n-type impurity layers arranged in a direction of <

100>

.

12. A solidification sensor as set forth in claim 1, wherein said substrate is made of a silicon monocrystal, and said strain sensor is made of an impurity layer formed on a surface of said substrate made of the silicon monocrystal.

13. A solidification sensor as set forth in claim 1, further comprising a temperature sensor.

14. A solidification sensor as set forth in claim 13, wherein said temperature sensor is provided in the strain sensor.

4. A solidification sensor as set forth in claim, wherein the substrate provided with the strain sensor has a U-like cross-sectional shape.

15. A method of detecting a solidification, comprising the steps of:

absorbing a liquid in a liquid absorbing portion,

causing a substrate to generate a strain due to a volumetric change of said liquid absorbing portion, and

detecting said strain exerted to said substrate.