CN201110899Y - Fiber optic icing sensor - Google Patents

Abstract

Fiber-optic icing sensors, which belong to photoelectric sensors, are used to detect icing conditions on the surface of objects. The purpose is to be more miniaturized, lighter in weight, better in sensitivity and minimum detection limit, and at the same time, no sensitive materials are required, and the production cost is reduced. The lower the signal processing is, the simpler it is. The ends of the transmitting optical fiber bundle and the receiving optical fiber bundle of the utility model are combined into a concentrated optical fiber bundle, and the end face of the concentrated optical fiber bundle constitutes the end face of the detection head; the other end of the emitting optical fiber bundle is equipped with a transmitting circuit, and the other end of the receiving optical fiber bundle is equipped with a signal detection circuit. The detection circuit is composed of a photodiode and a preamplifier circuit connected in series. The utility model has the advantages of small size, light weight, multi-point distribution, good electromagnetic compatibility, no movable accessories, high reliability and simple signal processing; it is suitable for detecting icing conditions on the surface of objects.

Description

Fiber optic icing sensor

technical field

The utility model belongs to a photoelectric sensor, in particular to an optical fiber type icing sensor, which is used for detecting the icing condition on the surface of an object.

Background technique

The icing sensors currently used for aircraft icing detection have many shortcomings: the radiation type is harmful to human health; the conductivity type has poor reliability; the differential pressure type has a large volume and complex structure. Moreover, none of these icing sensors can give quantitative information about the severity of icing. The recent magnetostrictive vibrating cylinder and piezoelectric resonant diaphragm icing sensors can give quantitative information on the severity of icing within a certain range of ice thickness, but the volume and weight of the magnetostrictive vibrating cylinder-type icing sensors are relatively large. Large, complex structure, high production cost, can only be installed on the fuselage, not flush and conformal installed on some parts of the aircraft, such as the leading edge of the wing, and the minimum detection limit is not satisfactory (0.254mm abroad, about 0.254mm domestically) is 0.300mm). Although the volume and weight of the piezoelectric resonant diaphragm type icing sensor is small, it can be installed flush and conformal on the curved surface of the machine, and the minimum detection limit can reach about 0.10mm, which is better than the magnetostrictive vibrating cylinder type, but it has higher requirements for sensitive materials. Strict, the production cost is higher, and the signal processing is more complicated.

Contents of the invention

The utility model provides an optical fiber type icing sensor, which aims to be more miniaturized, lighter in weight, better in sensitivity and minimum detection lower limit performance, does not need sensitive materials, has lower production cost, and is simpler in signal processing.

An optical fiber type icing sensor of the utility model includes a transmitting optical fiber bundle and a receiving optical fiber bundle, and is characterized in that: the ends of the emitting optical fiber bundle and the receiving optical fiber bundle are combined into a concentrated optical fiber bundle, and the end face of the concentrated optical fiber bundle constitutes a detection head End face; the other end of the transmitting optical fiber bundle is equipped with a transmitting circuit, and the other end of the receiving optical fiber bundle is equipped with a signal detection circuit. The signal detection circuit is composed of a photodiode and a preamplifier circuit in series.

The optical fiber type icing sensor is characterized in that: the distribution form of the transmitting optical fiber bundle and the receiving optical fiber bundle on the end face of the concentrated optical fiber bundle is random uniform distribution, concentric circle distribution or semicircular distribution.

The optical fiber type icing sensor is characterized in that: the shape of the end surface of the detection head is a threaded structure; the ends of the transmitting optical fiber bundle and the receiving optical fiber bundle are equipped with connectors with a threaded structure, which are used to connect the transmitting circuit respectively and signal detection circuit.

The ends of the transmitting optical fiber bundle and the receiving optical fiber bundle are combined to form a Y-shaped conductive optical fiber bundle, which constitutes the basic structure of the utility model. The end face of the concentrated optical fiber bundle constitutes the end face of the probe head, which is screwed into the surface of the measured object. When there is no ice on the surface of the measured object, the emitted light of the light-emitting device is transmitted along the emitting fiber bundle and the concentrated fiber bundle, and is injected into the air through the end face of the detection head, and the photodiode cannot detect any emitted light. When ice is formed on the surface of the object to be measured, the emitted light will produce reflected light, scattered light, transmission and absorption of emitted light in the ice layer, among which the reflected light at the ice layer-air interface and the part inside the ice layer The scattered light enters the receiving fiber bundle through the end face of the probe head, and the photodiode in the signal detection circuit converts the light energy obtained by the receiving fiber bundle into a current, which is converted and amplified into a voltage signal by the preamplifier circuit. Within a certain range of ice thickness, the voltage signal has a good single-value function relationship with the ice thickness, so the detection of the ice thickness can be realized by obtaining the voltage signal.

The utility model has the advantages of small size, light weight, multi-point distribution, good electromagnetic compatibility, no movable accessories, high reliability and simple signal processing; it is suitable for detecting icing conditions on the surface of objects.

Description of drawings

Fig. 1 is a schematic diagram of the utility model;

Fig. 2 is a schematic diagram of the circuit part of the utility model;

Fig. 3 is the structural drawing of the utility model embodiment;

Fig. 4 is the top view of the end face structure of the embodiment of the present invention, the emitting fiber bundle and the receiving fiber bundle are distributed in concentric circles on the end face of the concentrated fiber bundle;

Fig. 5 is the implementation state that the transmitting fiber bundle and the receiving fiber bundle are randomly and evenly distributed on the end face of the concentrated fiber bundle;

Fig. 6 is an implementation state of semicircular distribution of the emitting fiber bundle and the receiving fiber bundle on the end face of the concentrated fiber bundle.

Detailed ways

Now in conjunction with Fig. 1 to Fig. 4 the utility model is described in detail.

In Fig. 1, the ends of the transmitting optical fiber bundle 7 and the receiving optical fiber bundle 4 are merged into a concentrated optical fiber bundle 8, and its end face constitutes the end face 3 of the probe head, and its shape is a metal thread, which is convenient for screwing into the surface 2 of the measured object to achieve flushness installation purpose. The working wavelength of the light emitting device 6 in the transmitting circuit is near infrared, so as to eliminate the interference of the visible light in the background light to the detection circuit. When there is no icing on the surface 2 of the measured object, the emitted light from the light-emitting device 6 is transmitted along the emitting fiber bundle 7 and the concentrated fiber bundle 8 and enters the air through the end face 3 of the probe head, and the photodiode 5 cannot detect any emitted light. When ice is formed on the surface 2 of the object to be measured, the emitted light will produce reflected light as shown in RL in the figure, scattered light as shown in SL in the figure, and the transmission and absorption of emitted light in the ice layer 1. , the reflected light from the ice-air interface and part of the scattered light in the ice layer enter the receiving optical fiber bundle 4 through the probe end face 3, and the photodiode 5 in the signal detection circuit converts the light energy obtained by the receiving optical fiber bundle 4 into The current is converted and amplified into a voltage signal by the preamplifier circuit.

In FIG. 2, the photodetection circuit including the photodiode 5 is actually a converter that converts light into current and then into voltage. The photodiode 5 converts the light energy obtained by receiving the optical fiber bundle 4 into a current, which is converted and amplified into a voltage signal Vo by a preamplifier circuit.

Fig. 3 and Fig. 4 are an embodiment of the present utility model, and in Fig. 3, launch fiber bundle sheath 9, the thread nominal diameter of connector 10 is 4mm; 11. The transmitting optical fiber bundle 7 is located at the axis, and the receiving optical fiber bundle 4 is arranged in a coaxial and concentric circle with it. The nominal diameter of the thread of the end sheath 11 is 10mm. Using the front slope of its modulation characteristic curve for measurement can achieve higher sensitivity and facilitate signal processing. In addition, the coaxial arrangement is convenient to manufacture, and the structure is symmetrical, and the texture direction and the inclination of the measured surface have little influence on it.

The distribution form of the transmitting fiber bundle 7 and the receiving fiber bundle 4 on the probe end face 3 can also be a random uniform distribution as shown in FIG. 5 or a semicircular distribution as shown in FIG. 6 . The specific distribution form should be determined by comprehensively considering the ice thickness measurement range, sensor sensitivity, and size limitation of the combined optical fiber bundle. In FIGS. 4 , 5 and 6 , the slanted lines on the cross-section indicate the transmitting fiber bundle 7 ; the slanted lines on the cross-section indicate the receiving optical fiber bundle 4 .

Claims (3)

1. a fibre-optical freezing sensor comprises the launching fiber bundle and receives fibre bundle, it is characterized in that: described launching fiber bundle is with the reception optical fiber bundle end portion and become to concentrate fibre bundle, concentrates the end face of fibre bundle to constitute the detecting head end face; The launching fiber bundle other end is equipped with radiating circuit, receives the fibre bundle other end signal deteching circuit is housed, and signal deteching circuit is composed in series by photodiode and pre-amplification circuit.

2. fibre-optical freezing sensor as claimed in claim 1 is characterized in that: launching fiber bundle and reception fibre bundle distribute for evenly distribution at random, concentric circles distribution or semicircle at the end face distribution form of concentrating fibre bundle.

3. fibre-optical freezing sensor as claimed in claim 1 or 2 is characterized in that: the profile of described detecting head end face is a helicitic texture; Described launching fiber bundle and reception optical fiber bundle end portion are equipped with the connector of threaded structure, are used for connecting respectively radiating circuit and signal deteching circuit.

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