EP3784865B1 - Melting head for an ice melting apparatus - Google Patents

Description

The invention relates to a melting head of an ice-melting device, comprising an attachment area at the rear with respect to the propagation direction for attachment to a drilling device or a drill pipe and a heatable front area at the front with respect to the propagation direction, the front area having a radially outer surface area in which the front area in the Propagation direction up to the front axial melt head end in the external cross section tapers, in particular the outer diameter tapers, and the radially outer surface area surrounds an inner recess whose free internal cross section decreases from the axial melt head end counter to the propagation direction. A connection created from such a melting head and the drilling device or a rod assembly can then preferably form an ice-melting device.

Such a melting head is known, for example, from the publications SU 1 149 670 A1 , SU 1 087 648 A1 and DE 19 36 902 B1 .

The direction of propagation is understood to mean the direction in which the melting head or an ice melting device formed with it moves forward melting in the ice when used as intended. The direction of propagation preferably coincides with a center axis, in particular a center longitudinal axis of the melting head and/or an ice melting device formed therewith.

Melting heads of this type are generally known in the prior art and are used to drill holes in ice, in particular because the ice surrounding the melting head is melted by the heated front area of the melting head and the melting head, together with the drilling device or drill rods connected to it, is Gravity direction through the acting weight force penetrates into the depth. possibly an additional driving force can also be exerted by means of a drill rod.

The prior art and also the invention further described here can provide that heating elements within the melting head are supplied with energy that is provided by the drilling device or the rods.

For example, it can be provided that a drilling device forms a cylindrical housing, at the front end of which, in the direction of propagation, the melting head is attached with its rear attachment area. The melting head preferably has a maximum external cross section, in particular diameter, which corresponds to the cross section, in particular diameter, of the cylindrical drilling device. Inside the drilling device, for example, an energy source, possibly also additional electronics, can be carried along, in particular, for example, a supply of cable that can be unwound, in order to provide a communication option and/or energy transmission via the cable between the drilling device and the surface.

A possible area of application is, for example, drilling holes in water-ice, for example in glacier areas or arctic areas of the world. Another application is the creation of boreholes in the ice surface of distant astronomical bodies (e.g. planets, moons, comets, etc.). In particular, it should be noted that the term "ice" is not limited to water ice. For the purposes of the invention, ice is also understood to mean any other substance that is in the solid state and is converted into another state of aggregation by means of the heat of the melt drill head can be, particularly in the liquid state or even gaseous state.

As mentioned above, fusion heads of fusion drilling devices have heating elements with which heat is generated, e.g. by resistance heating, which is transported by thermal conduction between the heating element and the material of the fusion head to its outer surface in order to bring about the melting process there.

As a rule, heat is transported not only from the typically multiple heating elements to the outside to the surface of the front region of the fusion head heated thereby, but also into the interior of the fusion head and the entire drilling device, which can lead to problems.

For example, heat can build up inside, which can have an effect on the electronics or energy storage devices that are carried along. Furthermore, the heat given off to the inside is effectively not available or only available with reduced efficiency for heating the front of the fusion head and is therefore possibly lost via the rear areas of the fusion head or the drilling device without having contributed to the progress of the fusion drilling.

It is therefore an object of the invention to provide an improved melting head with which it is possible to overcome the disadvantages mentioned, in particular to make better use of the amount of heat given off to the outside and inside by heating elements in the melting head.

This object is achieved according to the invention in that in a region between the point of intersection of the inner recess with the central axis and the axial melt head end, the surface sizes of the radially outer surface area and the surface of the inner recess are the same and the surfaces projected in the propagation direction of the outer Surface area and the surface of the inner recess are equal.

The plane in which the axially front melting head end lies preferably also forms the plane of the opening of the inner recess. A normal vector on this (opening) plane preferably lies parallel to the propagation direction.

The outside and inside cross-sections mentioned here are viewed perpendicularly to the direction of propagation.

The result of this configuration according to the invention is that the heated front area has both a heated surface lying on the outside in the radial direction and a heated surface lying on the inside in the radial direction, namely that of the inner recess.

In particular, the radial direction is understood as being perpendicular to the propagation direction or central longitudinal axis of the melting head. Located radially on the inside and on the outside means in connection with the surfaces mentioned that the inner surface has a smaller radial distance to the central axis than the outer surface.

Both the inner and the outer surface of the front area are not parallel or inclined to the propagation direction due to the respective tapers in or counter to the axial direction to the propagation direction, so that the movement of the melting head in the propagation direction results in an effective application of force to the surrounding ice through these surface areas results.

Due to these inclinations of the inner and outer surfaces, when considering an imaginary projection of these surfaces in the direction of propagation or the central axis of the melting head, respective projection surfaces result which are therefore perpendicular to the propagation and are acted upon by the ice.

The inner projection surface actually corresponds to the inner free cross section of the inner recess in the plane of the front axial one melting head end. The outer projection surface forms a ring surrounding the inner projection surface, the outer cross section, in particular outer diameter, of which corresponds to the maximum outer cross section of the melting head and preferably of the entire drilling device.

The amount of heat emitted by the heat transport from the heating elements to the outside and inside can thus be dissipated to the environment much better, according to the invention in each case via the front area of the melting head, which contributes to improved drilling progress and prevents internal heat build-up.

Due to the embodiment described, the front axial melting head end forms a frame, in particular a ring, via which the radially outer surface area and the surface of the inner recess merge into one another. The end face of this ring pointing in the direction of propagation can, for example, be sharp-edged or crowned (or rounded) or flattened.

Due to the increase in the external cross-section of the radially outer surface area, starting from the front end of the melting head in the opposite direction to the propagation direction, and the reduction in the internal cross-section of the recess in the opposite direction to the propagation direction, the result is that the front area of the melting head forms an annular area that extends in the axial direction, the annular width of which is the difference between the external and internal cross-sections from the front axial melt head end against the direction of propagation increases, in particular up to the axial position of the bottom of the inner recess.

It represents a particularly preferred embodiment of the invention if the heating elements are arranged at least in certain areas, in particular at least with their tip areas that emit heat, in the material of the front area of the melting head, which is arranged between the tapering outer surface and the surface of the inner recess, i.e. actually in the material of the named ring area of the front area. Through this it is particularly well ensured that the heat emitted by the heating elements can be dissipated to the environment both via the tapered outer surface area and the inner surface of the recess by a particularly short, in particular almost radial transport and contributes to melting.

Particularly preferably, the melting head can comprise a plurality of heating elements, in particular which are each inserted in rearward recesses of the melting head, which in particular are open counter to the direction of propagation, the heating elements and/or recesses each having a radial distance from the central axis of the melting head which corresponds to the radial distance of the frame- or at least essentially corresponds to the annular, axially front melt head end, in particular corresponds to the radial spacing of the melt head end. The result of this is that the transport path to the inner surface and the transport path to the outer surface are at least essentially of the same length.

In particular, it can also be provided that the axial length of the tapering radially outer surface area and the axial depth of the inner recess are the same. This also contributes to the equalization of the heat transport.

According to the invention, the area sizes of the radially outer surface and the area of the inner recess are the same in a region between the point of intersection of the inner recess with the central axis of the melting head and the front axial end of the melting head. This ensures that at least essentially the same amount of heat can be transported away through these respective surfaces per unit of time, in particular which in turn equalizes the heat transport to the inside and to the outside.

Furthermore, it is provided according to the invention that, in combination with the aforementioned embodiment, the areas of the outer surface area and the area of the inner recess projected in the direction of propagation are the same are large, in particular since an at least substantially equal application of force then takes place as a result of the propagation onto the inner and outer surfaces.

In all possible embodiments, the invention can preferably provide that the surface area lying on the outside and the inner recess are configured n-fold rotationally symmetrically, preferably rotationally symmetrically, about a central axis of the melting head lying in the direction of propagation. With n-fold rotational symmetry, the outer and inner cross-section of the melting head (viewed perpendicularly to the propagation) is n-polygonal, or the respective outer and inner surfaces are faceted, and with a rotationally symmetrical design, the respective cross-section is therefore circular.

A preferred, in particular rotationally symmetrical geometry of the melting head can provide that the outer surface area and the surface of the inner recess each correspond to a cone section or a section of a paraboloid.

The invention can also provide that the tapering front area corresponds to a body of rotation which is rotationally symmetrical about the central axis, in particular a cone section or paraboloid section, the tip area of which is folded over on the plane in which the front axial end of the melting head lies, to form the recess towards the interior of the melting head.

In particular, the shape, in particular the cross-sectional shape viewed along the central axis of the outer surface area and the inner recess, apart from the sign and an axial displacement, in particular an axial displacement of twice the axial length of the front area, can obey the same mathematical function depending on the radial distance from the central axis .

Embodiments of the invention and embodiments not according to the invention are described in more detail with reference to the figures.

The Figures 1A to 1D show different geometries of the outer surface 1a and inner surface 1b of a melting head 1 in cross section, ie cut in a plane in which the central axis 2 of the melting head 1 lies. The Figures 1A and 1D show here inventive designs and the Figures 1B and 1C not according to the invention.

The propagation direction 3 is for everyone figures 1 using the arrow to the left of the figures 1 visualized.

It can be seen for all versions of the figures 1 that the front area 1c of the melting head 1 comprises the radially outer surface area 1a. This surface area tapers in cross section perpendicularly to the central axis 2 in the direction of propagation. With the rotational symmetry present here, the outer diameter of the outer surface area 1a thus decreases in a direction from the rear attachment area 4 to the axially front melting head end 1d. The start of the taper at the collar 1e preferably defines the axial start of the front area and the melting head end 1d the end of the front area.

The upper circular area representations over the Figures 1A to 1D visualize the surfaces of the radially outer surface area and the inner surface 1b of the respective recess 5 projected in the propagation direction or direction of the central axis 2. According to the information about the projected surfaces p1a and p1b, the versions represent the possibilities, the sizes of the surfaces 1a and 1b or to make the sizes of the projections p1a and p1b the same or different, in particular with the special advantages as they are mentioned in the general part of the description.

Figure 1A represents an embodiment according to the invention, in which the inner surface 1b and the outer surface 1a in the cross section shown here are each described by a parabola. The two parabolas differ only in the sign and an offset along the central axis 2 and are otherwise parameterized in the same way. The mathematical description thus obeys the cross-sectional shape of both surfaces of the same function depending on the radial distance to the central axis 2 apart from the offset and an inversion. Due to the rotational symmetry, Figure 1A in space the shape of a paraboloid section of both surfaces.

The same can be done for the Figures 1B to 1D apply, whereby the function describes a straight line here, which, given the rotational symmetry in space, leads to a cone section shape of both surfaces.

The figures 2 show various inventive embodiments of the melting head 1 according to Figure 1A , So with a respective paraboloid shape of the inner and outer surfaces 1b and 1a.

At Figure 2A the front axial melting head end 1d forms a sharp-edged shape on the axial end face Figure 2B forms the melt head end 1d a rounded or crowned shape and at Figure 2C a flattened shape.

The figures also visualize recesses 6 which serve to accommodate heating elements, or the heating elements 6′ themselves. This is supplementary in the figure 3 shown more clearly. It can be seen here that the recesses 6 or heating elements 6 ′ are all arranged on a circle with a radius which corresponds to the radial distance of the melting head end 1d from the central axis 2 .

As a result, at least the heat-dissipating tips of the heating elements 6' are preferably centered in the ring area 7 of the front area of the melting head, so that their heat can be dissipated both outwards and inwards over a short distance.

Right side in the figure 3 , which relates to possible embodiments according to the invention, it is shown that a drilling device 8 with a cylindrical housing is connected to the rear of the rear fastening area 4, which, for example, energy sources 9 for the heating elements 6', shown here only symbolically, or other electronics 9 or cable 10 can accommodate. The melting head 1 thus forms, together with this drilling device 8, an ice melting device.

figure 4 makes it clear that in the embodiment according to the invention, both the outer surface 1a and the inner surface 1b of the recess 5 are described by the same parabolic formula P and differ only in an inversion I and an offset O along the central axis 2.

. Hier gehen die Innenflächen und Außenflächen 1a, 1b ineinander über. R ist dabei der maximale Außendurchmesser des Schmelzkopfes 1 und h die Tiefe der Ausnehmung 5 bzw. Höhe des verjüngten Frontbereiches bzw. Ringbereiches 7.In the parameterization shown here, the axially front ring-shaped melting head end is at the position $\mathrm{right}=\frac{\mathrm{<figure-callout\; id="2"\; label="R\; \surd "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">R</figure-callout>}}{\surd }$

. Here the inner surfaces and outer surfaces 1a, 1b merge into one another. R is the maximum outer diameter of the melting head 1 and h is the depth of the recess 5 or the height of the tapered front area or annular area 7.

Claims (10)

1. Melting head (1) of an ice-melting device (1, 8), comprising a fastening region (4), which is rearward with respect to the propagation direction and is intended for fastening to a drilling device (8) or a drill pipe, and a heatable front region (1c), which is forward with respect to the propagation direction, wherein the front region (1c) has a radially outer surface region (1a), in which the outer cross section of the front region (1c) tapers in the propagation direction (3) as far as the forward axial melting head end (1d) and the radially outer surface region (1a) surrounds an inner recess (5), the free inner cross section of which decreases from the axial melting head end (1d) counter to the propagation direction (3), characterized in that, in a region between the point of intersection of the inner recess (5) with the centre axis (2) and the axial melting head end (1d), the surface areas of the radially outer surface region (1a) and the surface (1b) of the inner recess (5) are the same and the surfaces (pla, plb) of the outer surface region (1a) and the surface (1b) of the inner recess (5), projected in the propagation direction (3), are the same size.
2. Melting head according to Claim 1, characterized in that the melting head end (1d) forms a frame, in particular a ring, via which the radially outer surface region (1a) and the surface (1b) of the inner recess (5) merge into one another and the end face of which that faces in the propagation direction (3) has a sharp-edged or crowned or flattened form.
3. Melting head according to either of the preceding claims, characterized in that the outer surface region (1a) and the inner recess (5) have an n-fold symmetry of revolution, preferably a rotationally symmetrical form, about a centre axis (2) in the propagation direction (3).
4. Melting head according to one of the preceding claims, characterized in that the axial length (h) of the tapering, radially outer surface region (1a) and the axial depth (h) of the inner recess (5) are the same.
5. Melting head according to one of the preceding claims, characterized in that it comprises multiple heating elements (6') arranged at least in certain regions in the material of the front region (1c), which material is arranged between the tapering, radially outer surface region (1a) and the surface (1b) of the inner recess (5), in particular in the material of an axially extending annular region (7) of the front region (1c).
6. Melting head according to one of the preceding claims, characterized in that it comprises multiple heating elements (6'), in particular which are each inserted in rear recesses (6), wherein the heating elements (6') and/or recesses (6) have a respective radial distance from the centre axis (2) that at least substantially corresponds to the radial distance of the annular melting head end (1d), in particular corresponds to the radial distance of the melting head end (1d).
7. Melting head according to one of the preceding claims, characterized in that the outer surface region (1a) and the surface (1b) of the inner recess (5) corresponds to a respective cone portion or a portion of a paraboloid.
8. Melting head according to one of the preceding claims, characterized in that the tapering front region (1c) forms a rotational element, in particular cone portion or paraboloid portion, which is rotationally symmetrical about the centre axis (2) and the vertex region of which is folded over inwards in the plane of the melting head end (1d) to form the recess (5).
9. Melting head according to one of the preceding claims, characterized in that the shape, in particular the cross-sectional shape along the centre axis (2), of the outer surface region (1a) and the surface (1b) of the inner recess (5) irrespective of the sign (I) and an axial offset (O), in particular of twice the axial length of the front region (1c), satisfy the same mathematical function (P) depending on the radial distance from the centre axis (2).
10. Ice melting device comprising a melting head (1) according to one of the preceding claims, which, at its fastening region (4) which is rearward in the propagation direction (3), is connected to a drilling device (8), in particular wherein the drilling device (8) comprises an axially extending, cylindrical housing (8), which contains an energy store (9) for the heating of heating elements (6) of the melting head (1) and/or a cable store (10) which can be unspooled.

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