JP2002131011A - Detector for reduction of gap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a watching for reduction of a gap due to the operation of machines having a minute gap between a high speed rotating body such as a turbine wing or screw rotor and a fixed body such as a casing or the like. SOLUTION: In a detector for reduction of gap, a projection part 2 embedding a short-circuit line 22 is connected to a main body 1 passed through a lead line 11, two terminals 14 are conducted via the line 11 and the line 22. The main body 1 is connected to the projection part 2 with low connecting strength in comparison with the destructive strength caused by respective bending breakage of the body 1 and the projection part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus having both a fixed body and a moving body moving at a high speed with a small gap therebetween, and the size of the gap is determined by thermal deformation, load conditions, vibration and the like. The present invention relates to a means for detecting when the size of the image is reduced.

[0002]

2. Description of the Related Art In turbines, turbo compressors, screw compressors and the like, a high-speed rotating body called a turbine blade or a screw rotor is housed in a fixed body called a casing or the like, and moves therein. The size of the gap existing between the outer peripheral surface of the rotating body and the bore, which is the cylindrical inner wall surface of the fixed body, has an important meaning. If the gap is large, the backflow of the working fluid inside the device increases, resulting in a decrease in the performance of the device. On the other hand, when the gap is small, the possibility that the rotating body and the fixed body come into contact with each other increases. When the rotating body comes into contact with the fixed side, frictional wear is rapidly increased while generating vibration noise, so that not only cannot the operation be continued, but also there is a possibility that the equipment may be damaged. Therefore, these gaps should be managed so as to be small enough not to make contact.

[0003] The size of these gaps at rest can be measured relatively easily. It is a method of inserting a gap gauge, which is a small piece having a known thickness, into the corresponding gap, whereby it is possible to determine whether the gap is appropriate. But,
When the equipment is operated, changes in the load conditions due to thermal deformation and the acting fluid pressure and vibration occur, and the gap changes from the size at rest.

[0004] As a method of determining the gap between the moving body and the fixed body by measuring the displacement of the moving body, there are conventionally known the following types of detecting means. As described in Japanese Patent Application Laid-Open No. Hei 8-271204, an eddy current displacement meter detects the distance to an approaching conductive object from the inductance change of a high-frequency coil. As described in Japanese Patent Application Laid-Open No. H11-230704, a capacitance displacement meter measures a distance between a detector and a measurement object by using a capacitance having a functional relationship with the distance. As described in Japanese Patent Application Laid-Open No. 11-230704, an optical displacement meter reads the angle and phase of reflected light of an object and measures the distance to the object. However, it is difficult to apply these conventional displacement measuring means to the above devices for the reasons described later.

Further, as means for measuring the minimum gap in the operating state, a projection made of a soft material such as lead is provided on the inner surface of the bore, and the projection of the portion which comes into contact with the outer periphery of the rotating body is cut off by the operation of the apparatus. There is also known a method of measuring the height of a projection.

[0006]

None of the above non-contact displacement meters have specifications that can satisfy the clearance measurement of high-speed rotating bodies such as the above-mentioned turbines and screw compressors. The reason is that the outer circumference of the turbine blade and screw rotor is narrow in the rotation direction, and when viewed from the fixed side, the outer circumference of the rotating body passes in a very short time. Due to lack of detection. Also, even if there is sufficient measurement means with response speed,
In many cases, it could not be used due to the temperature and pressure inside the equipment and the nature of the fluid inside.

[0007] For the measurement using the soft material projection, it is necessary to reattach the projection for each test and disassemble the device after the operation, which is troublesome and time-consuming. In addition, it was not possible to determine under what operating conditions, such as the rotational speed and pressure conditions, the minimum clearance was reached. Further, in this method, even if the gap becomes smaller than a specified value in the case of an abnormality or the like, it cannot be known immediately and cannot be used as a judgment material for instructing an emergency stop for preventing contact.

[0008] An object of the present invention is to achieve the above object.
An object of the present invention is to realize a means for monitoring the size of a gap between a moving body including a high-speed rotating body and a fixed body from the outside and detecting the fact immediately when the size becomes smaller than a prescribed value.

[0009]

The above object can be attained by constructing a clearance reduction detecting device by the following first means.

[0010] The clearance reduction detecting device is composed of two parts, a main body part and a protruding part, which are joined together. The bonding strength is set to be weaker than the breaking strength when the main body and the projection are broken alone. At least two conductive wires penetrate the inside of the main body from one surface of the main body to which the protrusions are joined, and are drawn out from the other surface on the opposite side. On a surface other than these two surfaces of the main body, means for coupling to members other than the present device are provided. On the other hand, the protruding portion includes therein a conductor that short-circuits two of the conducting wires penetrating the main body. The protrusion may be made of an insulating material and a conductive material may be embedded therein, or the protrusion itself may be made of a conductive material. In any case, it has a function of electrically coupling the two conductors coming out of the main body.

If the following second means is used in addition to the above-mentioned first means, the function can be further increased.

A plurality of projections are provided for one main body, and the height of each projection from the joint surface is made different. Each projection short-circuits two of the conductors that penetrate the body, but at least one of these penetrations does not share the conductor with which the other projection short-circuits; Let through. The other one may pass through the main body independently without being shared, or may be connected to a conductor from another projection inside the main body to form a shared line.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a gap reduction detecting apparatus according to the present invention, FIG. 2 is a cross-sectional view showing a specification state when the apparatus is incorporated in a device, and FIG. 3 is a use state in FIG. It is a cross section schematic diagram.

The gap reduction detecting device comprises a main body 1 and a projection 2 which are joined on a joint surface 3 by an adhesive. The bond strength is usually strong enough to handle,
The strength is made weaker than the strength when the main body 1 and the protrusion 2 are individually broken.

The main body 1 has a substantially cylindrical shape, and two conductors 11 penetrate the inside from the end face to which the projection 2 is bonded to the other end face. The end of the conductive wire 11 is exposed to the outside, and a terminal 14 is provided. The outer periphery of the cylinder of the main body 1 is covered with an outer shell 13, and the external thread formed on the surface of the outer shell 13 serves as a connecting means with members other than the present device. The hollow hole of the outer shell 13 is filled with the insulating filler 12 together with the conductive wire 11. However, on the joining surface 3 side, the filling material 12 is provided with a concave portion at the center, and the end of the conductive wire 11 is exposed there.

The projection 2 is formed of a covering material 21 in which a short-circuit line 22 is embedded, and has an approximately cylindrical shape. The cylindrical diameter of the protrusion 2 is smaller than the female screw bottom diameter of the main body 1. The short-circuit line 22 is connected before the projection 2 is joined to the main body 1.
The connection is made 23 with both of the conductors 11, and the excess conductor is folded into the recess 15. Therefore, the two terminals 14 are electrically connected via the conductor 11 and the short-circuit line 22.

As shown in FIG. 2, in order to attach the present apparatus to a device, a screw hole is previously provided at a predetermined position of a casing 31 of the device, and the fixing portion 1 is screwed into the screw hole. The height overhanging from the bore surface is adjusted to the predetermined gap size H by the amount of screwing in, and fixed with the nut 35. When the device to which the present apparatus is mounted is stationary, there is a gap of size H or more between the outer periphery of the rotating body 32 and the bore surface 36, and the rotating body 32 and the projection 2
Does not contact.

A conduction detecting means is added at the end of the terminal 14, but here, the simplest battery and light bulb are used. In actuality, the present invention can be applied to a system that makes a buzzer sound or a light-emitting diode light up when insulated by an electronic circuit, interlocks with an interlock device of an operation control panel of a device, or collectively manages a plurality of the devices.

During operation of the apparatus, thermal deformation, changes in load conditions, and vibrations occur, and the casing 31 of the rotating body 32
The case where the relative position with respect to has changed to 33 will be described. As shown in FIG. 3, the outer peripheral tip of the rotating body 33 contacts the tip of the protrusion 2 and applies an impact force. Due to this impact, the weakest bonding surface 3 is peeled off, and the projection 2 falls off the main body 1. Almost at the same time, the connection 23 between the short-circuit wire 22 having no strength and the conductive wire 11 is also disconnected. The disconnection of the conductor can be immediately confirmed from the outside by turning off the light bulb of the detection circuit 34.

Since it is warned that the gap has been reduced to the specified value H by cutting the conductor, the operation of the device can be stopped or the operating conditions can be relaxed. By these operations, direct contact between the rotating body 33 and the bore surface 36 is prevented beforehand, and fatal equipment damage can be avoided. Further, by simultaneously recording the operating conditions (rotational speed, pressure condition, temperature condition, etc.) of the device at the time of contact, it is possible to grasp the operating condition in which the gap becomes smaller than a specified value.

Since the dropped projection 2 is small and light, the impact on the equipment can be neglected even if it collides with the rotating body. Further, the dropped projection 2 flows downstream with the flow of the working fluid, but can be captured by a strainer (wire mesh) provided in the middle.

According to the present embodiment, since the screw is used for the connecting means to the casing 31, it is easy to adjust the size H of the specified gap, and the fixing after the adjustment is reliable. Communication between the inner surface of the casing 31 and the outside world after passing through the screw portion can also be prevented by biting the seal tape or the sealant into the screw groove. Further, the covering material 2 of the projection 2
Since 1 can be selected, it is also possible to select, for example, to make the thermal expansion coefficient close to that of the casing 31, and to select the bonding strength by the type of the adhesive or the application method.

2) A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a sectional view of the gap reduction detecting device according to the present invention. Note that the description of the structure, operation, and effects that match the first embodiment is omitted.

The outer shell 13 made of metal is formed so as to partially project on the joint surface 3 in addition to the outer periphery of the cylinder. The conductive wire 11 and the short-circuit wire 22 are formed of one thin electric wire, and the covering material 21 and the filler 12 of the projection are integrally formed of the same polymer material. Joint surface 3
In this case, since the metal outer shell 13 and the polymer material are not bonded, the tensile strength at the boundary surface is almost equal. For this reason, the joint is that the protrusion 2 is connected to the filler 12 at the center of the end face of the outer shell 13 at the joint surface 3.

In the present embodiment, when the rotating body comes into contact with the projection 2 and applies an impact force, stress concentration occurs at the joint surface 3 which is the boundary between the covering material 21 and the filling material 12, and at this portion. Break. At the same time, since the conducting wire is also cut in the middle, conduction is lost, and contact can be confirmed from the outside.

According to this embodiment, the number of component types is reduced, molding is easy, and assembly can be simplified.
This device can be provided at low cost. Further, the joining strength can be adjusted by the area of the hole of the outer shell 13 on the joining surface 3.

3) A third embodiment will be described with reference to FIG. FIG. 5 is a sectional view of the gap reduction detecting device according to the present invention. Note that the description of the structure, operation, and effects that match the first embodiment is omitted.

The joint surface 3 of the main body 1 has three projections 2
a, 2b, 2c are provided, and the height from each joint surface is H
Change to 1, H2, H3. The structure of each protruding portion is the same as that of the first embodiment, except that one of the short-circuited wires penetrates the main body 1 and the terminals 14a, 14b,
14c, but the remaining one is connected to three to form one and the common terminal 16 is provided through the main body 1.

When the apparatus is mounted on a device, care should be taken not to interfere with each other when the three projections are broken. For example, the rotation direction of the rotator is set to a direction from the low protrusion 2c to the high protrusion 2a, or the rotation direction is set to a direction perpendicular to the sheet of FIG.

When the gap is reduced due to the operation of the device, the contact is made in descending order of the height, and peeling is detected on the joint surface 3. The breakage of the protrusion is determined by the disconnection of conduction between the common terminal 16 and the terminals 14a to 14c of each protrusion.

According to the present embodiment, the following effects can be expected.

First, in the case where a sudden stop or a decrease in operating conditions during operation of important equipment may lead to a large loss, the loss can be suppressed. In the contact stage of the first projection 2a,
The gap is prevented from being further reduced by, for example, gradually reducing the operating conditions without an emergency stop of the device. Nevertheless, if the second projection 2b comes into contact, the related department is warned that the operating conditions may be further relaxed and that an emergency stop may be performed. Further, when the third projection 2c comes into contact, the emergency stop is performed. By taking steps in this way, it is also possible to reduce the influence only by alleviating the driving conditions, and it is possible to secure a sufficient time margin by giving a warning in advance even during an emergency stop. Of course, the maintenance of this equipment is necessary when the stop becomes possible due to the operation of the substitute machine or the like.

As a second effect, when the present apparatus is used in the research and development stage, severe operating conditions are gradually added, whereby it is possible to quantitatively grasp how much the gap has been reduced. The use of three of the present apparatus according to the first embodiment can be substituted, but this is an effective means when there are restrictions on the mounting position or when it is desired to accurately set the difference in contact height.

[0034]

According to the present invention, the reduction of the gap can be externally monitored in a high-speed rotating body or the like that moves with a small gap between the fixed body and the fixed body. If the gap breaks below the specified value, conduction between the terminals of the device will be cut off, and this information will be used to relax the operating conditions of the device or to make an emergency stop to prevent damage to the device before it occurs can do.

Further, by recording the operating conditions (rotational speed, pressure condition, temperature condition, etc.) of the device when it is confirmed by the present apparatus that the gap has become smaller than the specified value, the gap can be reduced to the specified value. It is possible to grasp the conditions for the reduction. Furthermore, by utilizing this data,
The operating conditions under which the gap is reduced to the specified value are known, and an operating method of a device that prevents the abnormal reduction of the gap and subsequent contact without using this device can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a gap reduction detecting device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a use state when the apparatus of FIG. 1 is incorporated in a device.

FIG. 3 is a schematic cross-sectional view at the moment when a gap is reduced in the use state in FIG. 2;

FIG. 4 is a sectional view of a gap reduction detecting device according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a gap reduction detecting device according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body part, 2 ... Projection part, 2a ... Projection part, 2c ... Projection part, 3 ... Joint surface, 11 ... Conducting wire, 12 ... Filler, 13 ... Outer shell, 14 ... Terminal, 14a ... Terminal, 14b
... terminal, 14c ... terminal, 15 ... recess, 16 ... common terminal,
Reference numeral 21: covering material, 22: short-circuit wire, 23: short-circuit wire joint, 3
DESCRIPTION OF SYMBOLS 1 ... Casing, 32 ... Rotating body, 33 ... Rotating body in operation, 34 ... Detection circuit, 35 ... Nut, 36 ... Bore surface.

Claims (1)

[Claims] 1. A detecting device comprising: a main body having at least two conductors penetrating therein; and a projection having therein a conductor for short-circuiting two of the conductors penetrating the main body. A structure in which the main body and the projection are joined together, and the main body and the projection are provided with coupling means for connecting members other than the present device on the joining surface and the surface other than the lead-out portion of the through conductor. A reduced joint strength between the main body and the protruding portion as compared with a breaking strength for breaking the gap.