FR2730787A1 - Probe investigating insides of for steam tubes - Google Patents

Abstract

The probe (1) has a housing (3A-C) connected to a semi-rigid tube (4). The probe has guides for centring it within a steam tube, formed by a group of at least three fingers (7) which are regularly spaced around the probe housing. Each finger is positioned in a radial seating (8) communicating with an axial bore and actuated by a return spring (1) in the seating. The expansion of the fingers is actuated by a pressure fluid in the axial bore (9) via the feed tube. The middle section of the probe carries the sensing instruments. The probe is connected to the end of the feed tube by an olive (5).

Description

Tube probe
The present invention relates to a probe for tubes.

 To find out the condition of the tubes of a steam generator, a steam condenser, etc., investigation tools are introduced into the tubes. It can be probes of various kinds depending on the physical parameters studied: ultrasonic probe, eddy current probe, vibrating probe ...

 It is necessary to guide and center the probe in the tube studied and also to fix it in the tube.

 Currently, flexible brushes, split tulips or spring pins are used for centering. For locking, a system of expansive clamps is used, the slats of which slide on inclined planes.

 However, flexible guidance systems have the disadvantage of random centering. The spring pin system has the drawback of poor friction control. The clamp system is too fragile and complex to carry out.

 The object of the present invention is to propose an effective and simple means for centering and locking a tool or a probe in a tube.

 In the remainder of the text, the word "probe" designates any object, tool, detector carrying out investigations or carrying out work, introduced inside a tube.

 The subject of the invention is thus a probe for tubes comprising a body connected to a semi-flexible sheath, comprising centering and locking means in a tube, characterized in that said means comprise at least one group of at least three fingers regularly distributed around the probe body, each finger being housed in a radial housing communicating with an axial hole and being subjected to the action of an elastic retraction means in said housing, the expansion of the fingers coming from the sending pressurized fluid in said axial hole through said sheath.

We will now give the description of an exemplary implementation of the invention with reference to the appended drawing in which:
FIG. 1 represents a probe according to the invention.

 Figure 2 is a section along ll-ll of Figure 1 without the centering fingers.

 Figure 3 shows in enlarged view and in section the front part of the probe of Figure 1 showing the centering and fixing fingers.

 Referring to the figures, we see a probe 1 intended to carry out investigations inside a tube 2. This probe is of any kind. It can even be a tool.

 It comprises a body, in three parts 3A, 3B and 3C in the example shown. Part 3B is supposed to contain said investigative bodies, not shown because they have nothing to do with the invention. The probe is connected at its rear to a semi-flexible sheath 4 by means of an olive 5 set on the sheath and a ring 6 screwed onto the part 3C of the probe body and resting on the olive 5. This sheath is for example wound on a drum and is unwound as the probe is inserted into the tube 1. The probe is directly pushed into the tube by the semi-flexible sheath. The sheath contains the connections connecting the investigation organs of the probe to visualization, processing, etc. organs of the signals, information, supplied by the probe and possibly connections for orders supplied from the outside to certain organs. of the probe.

 The probe 2 comprises two groups of three fingers 7 for centering and locking the probe in a tube 2.

 A first group is located in the part 3A of the body and a second group in the rear part 3C.

 These two groups of three fingers are identical. They are housed 1200 from one another in radial housings 8 (see FIG. 2), opening onto an axial hole 9 which communicates with the sheath 4.

 As seen in Figure 2, the holes 8 form countersinks opening into the axial hole 9, but having a bottom 10 on which rests each finger 7 pushed by a spring II. The spring 11 bears on the one hand against a flange 12 of the fingers 7 and on the other hand against a cap 13 forced into the counterbores 8. The fingers 7 rest on the bottom 10 of the counterbores 8 by an enlarged foot 14 of the fingers 7.

 A seal 15 is placed on each finger 7 between the flange 12 and the enlarged base 14.

 At rest, the fingers 7 are in the retracted position, as can be seen in FIGS. 1 and 3.

 When the probe is sent into a tube 2, in order to center it in the tube, a fluid under pressure, for example air, is sent into the axial hole 9, for example so as to bring out the three fingers 7 In order not to trap air, which would prevent the fingers from coming out, the caps 13 are each pierced with a vent 16.

 The stiffness of the three springs 11 being identical, as well as the surface of the three fingers 7 offered to the thrust of the compressed air, this results in an identical output of the three fingers ensuring good centering of the probe.

 Depending on the pressure of the fluid, it is ensured that the probe is locked at a given point on a tube, only its centering, but with the possibility of sliding inside the tube.

 Of course, the invention is not limited to three centering fingers, nor to a probe of circular section.

Claims (1)

CLAIM Probe (1) for tubes (2) comprising a body (3A, 3B, 3C) connected to a semi-flexible sheath (4), comprising means for centering and locking in a tube (2), characterized in that said means comprise at least one group of at least three fingers (7) regularly distributed around the body of the probe, each finger (7) being housed in a radial housing (8) communicating with an axial hole and being subjected to the action elastic means (11) for retraction in said housing (8), the expansion of the fingers (7) coming from the sending of a pressurized fluid into said axial hole (9) via said sheath (4).