WO2014086421A1

WO2014086421A1 - Temperature sensor comprising moving screen for displacing contaminants

Info

Publication number: WO2014086421A1
Application number: PCT/EP2012/074598
Authority: WO
Inventors: Igor Dorrestijn; Vratislav ONDRAK
Original assignee: SKF AB
Current assignee: SKF AB
Priority date: 2012-12-06
Filing date: 2012-12-06
Publication date: 2014-06-12
Anticipated expiration: 2015-06-06

Abstract

The present invention provides an apparatus (1) for measuring the temperature of a surface within a gearbox, the apparatus comprising a screen (25) and a contactless temperature sensor (20), wherein the contactless temperature sensor is arranged to receive radiation through said screen for determining the temperature of the surface, wherein said screen is configured to move for displacing contaminants deposited on said screen.

Description

TEMPERATURE SENSOR COMPRISING MOVING SCREEN FOR

DISPLACING CONTAMINANTS

Technical field The present invention relates generally to the field of remote sensing and condition control and management. In particular, the present invention relates to a sensor unit for use in hazardous or contaminated environments, such as the insides of gearboxes and other oil-containing environments. Background

It is known to include sensors within vehicle components in order to record performance data and also to monitor conditions in critical equipment to predict and avoid component failure. In particular, it is known to use temperature sensors to check that components are within their intended working environment and are working within their specific tolerance.

Accordingly, it is an object of the present invention to provide an improved temperature sensor and/or tackle at least some of the problems associated with the prior art or, at least, to provide a commercially useful alternative thereto.

Summary

In a first aspect, the present invention provides an apparatus for measuring the temperature of a surface within a gearbox, the apparatus comprising a screen and a contactless temperature sensor,

wherein the contactless temperature sensor is arranged to receive radiation through said screen for determining the temperature of the surface, wherein said screen is configured to move for displacing contaminants deposited on said screen.

The present disclosure will now be further described. In the following passages different aspects of the disclosure are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

The present inventors have discovered that when sensors are used in, for example, engine components, the presence of the oil and grease can cause distorted or inaccurate readings. In particular, rather than record the temperature of a specific surface, such as a gear cog, the sensor may simply record the temperature of grease deposited on the sensor. The inventors have therefore found a means to ensure that the sensor is clear to make accurate readings without being hampered by the presence of contaminants.

A contactless temperature sensor is a device designed to take measurements of the temperature of a surface remotely by the capture of radiation emitted by a surface whose temperature is to be measured. That is, the contactless temperature sensor is preferably a single thermopile, a thermopile array or an infrared heat imaging camera module.

Contaminants are any material that could be deposited on the screen to obscure, alter or prevent the taking of a reading. Such contaminants include at least the grease and oil present in a gearbox or engine environment.

The screen serves to protect the temperature sensor from the environment but to also let through the radiation required for the sensor to function. Preferably the screen is infrared transparent. Suitable materials for the screen include silicon and polyethylene

Preferably the screen has oil-repellent properties, to further facilitate the displacement of oil and similar deposits from the screen. In one example, the screen is provided with an oleophobic coating. In a further example, the screen is provided with a surface texture that is "self-cleaning" and which repels oil droplets, as well as moisture droplets and other contaminants.

The screen of the present invention is designed to move for displacing contaminants from the surface of the screen. Preferably the screen is configured to move by rotating. Rotation includes oscillation in alternate directions. The screen is preferably flat and the rotation is preferably substantially in the plane of the screen. As the screen rotates the resulting centrifugal force drives the contaminants off the screen. In another embodiment, the screen is configured to move by vibrating. This may be achieved, for example by using a piezoelectric motor. This embodiment is less preferred since it is less efficient at clearing larger deposits.

In order to save energy, the screen is preferably stationary unless a temperature measurement is to be recorded. That is, the screen may be moved intermittently or on a schedule to ensure that when the measurement is being taken the screen is clear.

Preferably the apparatus of the present invention is provided within a housing. This serves to protect the sensor equipment from direct contact with the contaminants and the harsh operating environment. Preferably an upper surface of the screen is flush with or only slightly recessed within the housing, to help displace the contaminants from the apparatus. In one embodiment, the sensor is located within an engine or a gearbox. These environments are especially suited for the use of the sensor of the present invention.

According to a second aspect, the present invention provides a method of measuring the temperature of a surface within a gearbox or engine, the method using the apparatus of any of the preceding claims located within the gearbox or engine, the method comprising moving the screen to displace any contaminants deposited on said screen and

measuring the temperature of the surface with the contactless temperature sensor.

Figures

The disclosure will now be described in relation to the following non-limiting figures, in which: Figure 1 shows a cross-sectional schematic of a temperature sensor unit in accordance with the present invention. Figure 2 shows a three-dimensional schematic of a temperature sensor in accordance with the present invention.

Figure 1 shows an example of a temperature sensor unit 1 . The unit 1 comprises a housing 5 defining a cavity 10. A motor 15, thermopile array 20 and a screen 25 are mounted in the housing 5. The screen 25 covers the thermopile array 20 and is made of an infrared-transparent material such as silicon or PE. An outer surface of the screen is provided with an oleophobic coating, which is likewise infrared- transparent. The screen 25 is rotationally supported relative to the housing 5 by means of a bearing 30. The screen is mounted to an inner ring of the bearing 30, which ring is driven by an output shaft 45 of the motor 15. The motor 15 is connected to an external power source (not shown), and the thermopile array 20 is connected to an output circuit (not shown), both via an opening 50 into the housing 5. In use, the screen 25 allows the transmission of external infrared radiation (not shown) to the thermopile array 20, generating a response voltage. Independently, a voltage is applied across the motor 15 to drive its rotation. The torque of the rotating shaft 45 of the motor 15 is transferred to the bearing inner ring, causing the inner ring and mounted screen 25 to rotate. The rotation of the screen 25 will fling off oil and other contaminants that splash onto the screen. Furthermore, rotation of the screen 25 gives rise to a centrifugal force that drives any deposited oil (not shown) to the periphery of the screen 25. The screen 25 may be flush with an outer rim 35 of the housing such that the oil is flung off upon reaching the periphery. When, as in the depicted example, the screen 25 is slightly recessed relative to the outer rim 35, the thermopile array is suitably located so as to lie beneath a central region of the screen 25.

Thus, oil is flung off or is prevented from remaining on the part of the screen that covers the thermopile array 20, and hence the temperature recorded by the thermopile array reflects that of the external infrared-emitting target (not shown) rather than that of the oil.

The temperature sensor unit 1 is installed within a gearbox of an engine (not shown) in order to read the operating temperature of the gears and to ensure that there are no deviations from the expected conditions.

Although preferred embodiments of the disclosure have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the scope of the disclosure or of the appended claims.

Claims

Claims:

1 . Apparatus for measuring the temperature of a surface within a gearbox, the apparatus (1 ) comprising a screen (25) and a contactless temperature sensor (20), wherein the contactless temperature sensor is arranged to receive radiation through said screen (25) for determining the temperature of the surface, wherein said screen is configured to move for displacing contaminants deposited on said screen.

2. The apparatus according to claim 1 , wherein said screen (25) is infrared transparent.

3. The apparatus according to any of the preceding claims, wherein said screen (25) is made of silicon or polyethylene.

4. The apparatus according to any of the preceding claims, wherein an outer surface of said screen (25) is provided with an oleophobic coating or with a fluid- repellent surface texture.

5. The apparatus according to any of the preceding claims, wherein the contactless temperature sensor (20) is a single thermopile, a thermopile array or an infra-red heat imaging camera module.

6. The apparatus according to any of the preceding claims, wherein the screen is configured to move by rotating.

7. The apparatus according to any of claims 1 to 5, wherein the screen is configured to move by vibrating.

8. The apparatus according to any of the preceding claims, wherein the movement of the screen is driven by a motor (15).

9. The apparatus according to any of the preceding claims, wherein the screen (25) is stationary unless a temperature measurement is to be recorded.

10. The apparatus according to any of the preceding claims, provided within a housing (5).

1 1 . The apparatus according to claim 10, wherein an upper surface of the screen (25) is flush with an outer rim (35) of the housing (5).

12. The apparatus according to any of the preceding claims, wherein the contactless temperature sensor (20) is arranged beneath a central region of the screen (25).

13. A method of measuring the temperature of a surface within a gearbox or engine, the method using the apparatus of any of the preceding claims located within the gearbox or engine, the method comprising moving the screen to displace any contaminants deposited on said screen and