DE102020006614A1 - Electric heating sleeve - Google Patents

Abstract

The object of the invention is to develop an electrical heating sleeve for heating the valve spindle housing of valves used in high-temperature energy technology, which is resistant to the salts and acids used in high-temperature energy technology, and which under very extreme conditions, such as high daily outside temperature fluctuations, extremely high Humidity, with a heating temperature of the heating sleeve of up to 750 °C, a highly precise and very reliable temperature control is guaranteed over a long service life. The electric heating sleeve (1) according to the invention with two half-shells (3) made of cast material, which have an inner contour (4 ) and have an approximately cylindrical outer lateral surface (5) on the outside, is characterized, among other things, by the fact that the two half-shells (3) are completely identical in construction, and a separate terminal box (7) for power supply is arranged on each of the half-shells (3), U.N d that a spacer tube (9) is arranged between the half-shell (3) and the terminal box (7) assigned to it, and that around the outer lateral surface (5) of the half-shell (3) there is a spacer tube approximately in its thickness dimensions of the length of the spacer tube ( 9) appropriate thermal insulation (14) is arranged. The invention relates to an electrical heating sleeve for heating the valve spindle housing of valves used in high-temperature energy technology.

Description

The invention relates to an electrical heating sleeve for heating the valve spindle housing of valves used in high-temperature energy technology, which are used in particular in connection with solar thermal power plants, mostly under very extreme conditions (such as in the desert), in order to use the superheated steam to operate the electrical to produce turbines.

During the course of the day's solar radiation, the brines are heated by solar cells. Temperatures of over 700°C occur here. These brines are pumped through the valves into appropriately insulated tanks and at night, when the outside temperatures drop, to generate superheated steam and then removed/drained/pumped back from the storage tanks through these valves to operate the turbines. The rapid temperature changes that occur can result in a drop in temperature. At minus 27°C, the salts freeze and make the valves unusable, which is why the adjusting spindles are heated.

In the prior high-temperature energy technology electric heaters for such valve stem housing are known, as in the 1 shown, consist of a tubular heating element wound around the respective valve spindle housing, which is additionally encased with insulating material for thermal insulation (insulating material not included in the 1 shown). During assembly, as well as in the event of a defect for repairs, the complete spindle head must be dismantled with this spindle heater constructed in this way, ie for the installation and replacement of the tubular heater.

In the prior art, despite the use of this electrical heating of the valve spindle housing, for example if the hot salts stored in liquid form at approx , at a valve temperature of, for example, approx. +27°C, the salts passed through the valve solidify in the valve body.

This inevitably means that the valve spindle can no longer be adjusted, i.e. that the valve is no longer functional.

The uncontrolled "frozen" valves then have to be completely removed and then repaired, which is very costly and time-consuming.

Special heating sleeves for heating tubular objects are already described in the prior art, particularly in the field of plastics processing.

That's it DE 34 28 539 A1 a heating collar for heating tubular objects, in particular for injection nozzles of plastic injection molding machines, is known, which consists of two bent metallic plates, for example made of an aluminum alloy, and which are bent according to the circumference of the respective tubular object and attached to the tubular object by means of a pipe clamp are tense. It is essential that in the concavely curved inner surface of each of the plates there are grooves running parallel to the axis, into which, before the plates are bent, tubular heating elements in the form of heating cartridges are inserted.

This from the DE 34 28 539 A1 However, the known solution is by no means suitable for use in high-temperature energy technology, since these are not designed for rapid temperature changes of several 100° C. and they are not suitable for brine.

In addition, from the DE 4013538 A1 another temperature control device for plastics processing machines is known, which is formed by two half-shells, which are produced in the die-casting process, for example from aluminum. Temperature control elements are cast into these half-shells, which can be used as a heating element or as a cooling element, depending on requirements.

Due to the process, these temperature control elements have supporting surfaces which are not covered by the cast metal and which are directed towards both the inner and the outer lateral surface of the half-shell and which are required to secure the position of the temperature control element during injection molding.

This according to the in the DE 4013538 A1 The half-shells produced in the solution presented are placed on the surface to be tempered and braced using tensioning straps.

This after the DE 4013538 A1 However, the half-shells made of aluminum cannot be used in high-temperature energy technology at heating temperatures of the heating sleeve of up to 750 °C, since aluminum already becomes "soft" in the temperature range of 300 °C to 400 °C and melts at around 660 °C.

In addition, there is a significantly increased tendency to corrosion in the area of the support surfaces at significantly lower temperatures, even under normal boundary conditions makes it completely impossible to use under the extreme and salty conditions of high-temperature energy technology.

Furthermore, from the DE 10 2010 021 968 A1 a surface heating device, here for heating a container, is known, which comprises at least one heat transfer body on which at least one heating element is arranged.

This heating element is a conductor that can be charged with electrical energy, has electrical insulation from the heat transfer body and can also be bent without being destroyed. In an advantageous embodiment of the DE 10 2010 021 968 A1 the conductor is in the form of a heating wire and the insulation is in the form of a plastic sheath in contact with the heating wire.

Also these in the DE 10 2010 021 968 A1 The solution presented is not suitable for use in high-temperature energy technology, since the heating wire is covered with a plastic sheath and is therefore not suitable for temperatures up to a maximum of 750 °C.

It is therefore the object of the invention to develop an electric heating sleeve for heating the valve spindle housing of valves used in high-temperature energy technology, which can be installed easily and quickly, but also maintained easily, quickly and inexpensively, but which also prevents the valves from "freezing". should be completely avoided, and which should at the same time enable energy-efficient heating of the valve spindle housing, should be resistant to the salts and acids used in high-temperature energy technology, and which should also be used under very extreme conditions, such as daily outside temperature fluctuations in the range of minus 10 °C above the dew point up to plus 60 °C, an extremely high humidity, with a heating temperature of the heating sleeve of up to a maximum of 750 °C, a highly precise and very reliable temperature control over a long service life is to be guaranteed, and which is also easy to manufacture in terms of production technology en can.

According to the invention, this object is achieved by an electrical heating sleeve 1 for valve spindle housings 2 used in high-temperature energy technology, according to the features of the main claim of the invention.

Advantageous designs, details and features of the invention result from the dependent claims and from the following description of the exemplary embodiment according to the invention in connection with the exemplary embodiment of five representations of a possible design of the solution according to the invention.

• 1 : eine im Stand der Technik, in der Hochtemperaturenergietechnik, eingesetzte elektrische Heizung für Ventilspindelgehäuse 2, die aus einem um das jeweilige Ventilspindelgehäuse 2 herum gewickelten, elektrischen Rohrheizkörper 6 besteht;
• 2 : eine Halbschale 3 der erfindungsgemäßen Heizmanschette 1 zur Beheizung der Ventilspindelgehäuse 2 der in der Hochtemperaturenergietechnik eingesetzten Ventile, in einer Draufsicht;
• 3 : die Seitenansicht zu der in 2 dargestellten Halbschale 3 der erfindungsgemäßen Heizmanschette 1;
• 4 : die räumliche Darstellung der erfindungsgemäßen Heizmanschette 1 in einer Zusammenbauzeichnung, wobei diese aus zwei baugleichen erfindungsgemäßen, in den 2 und 3 dargestellten, Halbschalen 3 besteht;
• 5 : eine an einem Ventilspindelgehäuse 2, gemäß der 4, montierte erfindungsgemäße Heizmanschette 1 mit Wärmedämmung 14, d.h. im wärmegedämmten Endmontagezustand, in der Draufsicht;
• 6 : die Schnittdarstellung bei A-A, gemäß der 5.

The illustrations show in the

• 1 : an electric heater for valve spindle housing 2 used in the prior art, in high-temperature energy technology, which consists of an electric tubular heater 6 wound around the respective valve spindle housing 2;
• 2 : a half-shell 3 of the heating sleeve 1 according to the invention for heating the valve spindle housing 2 of the valves used in high-temperature energy technology, in a plan view;
• 3 : the side view to the in 2 shown half-shell 3 of the heating sleeve 1 according to the invention;
• 4 : The spatial representation of the heating sleeve 1 according to the invention in an assembly drawing, this being made up of two identical constructions according to the invention 2 and 3 shown, half-shells 3 consists;
• 5 : one on a valve stem housing 2, according to 4 , Mounted heating collar 1 according to the invention with thermal insulation 14, ie in the thermally insulated final assembly state, in plan view;
• 6 : the sectional view at AA, according to the 5 .

The in the 2 until 6 illustrated, according to the invention, electric heating sleeve 1 for valve spindle housing 2 used in high-temperature energy technology consists of two identical, ie identically constructed, in the 2 and 3 shown, consisting of cast material half-shells 3, which have an inner contour 4 on the inside as a contact surface to the jacket of the valve spindle housing 2, and an approximately cylindrical outer jacket surface 5 on the outside.

In each of the half-shells 3, as in the 2 and 3 shown, in each case an originally linear electrical tubular heating element 6 deformed in a meandering manner by bending is cast in such a way that its electrical connection points open into a terminal box 7 arranged on the heating sleeve 1 .

The casting of the tubular heating elements in the half-shells 3 results in a stable and secure construction of the respective half-shell 3, which enables the heating sleeves 1 to be used in a robust, reliable manner even under the most extreme operating conditions.

The size and heating capacity of the heating sleeves 1 used in each case can be optimally adapted to the valve spindle housing design to be heated by the sand casting process used in the production of the half-shells 3 .

The tubular heating elements 6 are always arranged in the half-shells 3 and cast there in such a way that an even heat distribution is ensured on the inner surface, the inner contour 4 of the heating sleeve 1 .

According to the invention is that in the connection area of the two half-shells 3 mounting brackets 8 are always arranged to connect the two half-shells 3 to each other.

In the present exemplary embodiment, both half-shells 3 are screwed together via six cast-on mounting brackets 8 .

The use of mounting brackets 8 makes it possible to quickly mount and dismantle the heating sleeves 1 according to the invention. Advantageously, 8 through holes 17 for receiving clamping screws 18 are arranged in these mounting brackets.

In the present exemplary embodiment, a through hole 17 is arranged in each of the mounting brackets 8 .

Through the use of arranged in these through holes 17 clamping screws 18, the two half-shells, after they have been placed around the valve stem housing 2, as in the 4 and 5 shown, are screwed together.

However, it is also important that the inner contour 4 of the half-shells 3 can be optimally and precisely adapted in size and shape to the outer contour, i.e. also to the outer diameter of the valve spindle housing 2 to be heated, by mechanical processing after casting, so that a very energy-efficient Heating of the valve stem housing 2 is guaranteed. It is also characteristic that a separate terminal box 7 for the power supply is arranged on each of the half-shells 3 of identical construction.

This makes it possible for each half-shell 3 of the heating sleeve 1 to be easily and inexpensively replaced separately and also maintained separately within the scope of maintenance at a reasonable cost. In addition, this ensures redundancy, which, for example, in the event of the failure of a thermocouple 11, ensures rapid error detection and continued operation until repairs are made, thereby improving reliability.

According to the invention, the cast material of the half-shells 3 consists of the brass alloy CC761S.

This brass alloy is resistant to salt water and can be operated continuously up to a temperature of 700°C and a maximum of up to a temperature of 750°C.

It is also important that the material 1.4541 (X6CrNiTi18-10) is used as the casing 15 for the tubular heating element 6 .

In combination, the materials used, i.e. the respective casting material used according to the invention in conjunction with the steel alloy used according to the invention for the casing 15 of the tubular heating element 6, cause the tubular heating element 6 to withstand the casting temperature due to the joint expansion behavior of these materials used according to the invention during casting.

The encapsulated tubular heaters used in the exemplary embodiment according to the invention have a diameter of 6 mm.

It is also essential to the invention that a spacer tube 9 is arranged between the half-shell 3 and the terminal box 7 assigned to it, which also distances the terminal box 7 from the lateral surface 5 of the half-shell 3 and stabilizes it safely and reliably, and in addition to safe cable routing, also the installation of others assemblies enabled.

It is essential that the spacer tube 9 is cast into the respective half-shell 3 or is firmly/rigidly anchored in an adapter plate 16 hard-soldered to the half-shell 3 .

In the present exemplary embodiment, the spacer tube 9 consists of a U-profile made of the material 1.4301 (X5CrNi18-10) and is firmly anchored in the sprue nozzle 16 in the respective half-shell 3 .

It is also essential to the invention that the end regions 10 of the tubular heating element 6 arranged in the spacer tube 9 are designed as cold ends 10 (i.e. without heating coils).

The electrical connection of the tubular heating elements ends in the terminal box 7.

The structure according to the invention, with the spacer tube 9 according to the invention and the inventions end regions 10 of the tubular heating element 6 arranged as cold ends 10 in the spacer tube 9 according to the invention, causes a thermal decoupling according to the invention of the terminal box 7 with the electrical connection points of the lateral surface 5 of the heating jacket 1, which then ensures reliable continuous operation of the heating jacket 1 according to the invention at high operating temperatures of up to 750 °C allowed.

It is also important that the terminal box 7 itself consists of stainless steel, as a result of which the entire heating sleeve 1 can be designed very cost-effectively in such a way that the degree of protection IP67 is guaranteed.

It is also essential that a thermocouple 11 is arranged in the spacer tube 9, which serves as a measuring system for temperature control in order to prevent the respective valves from “freezing”.

It is also characteristic that the measuring point 12 of the thermocouple 11 is arranged in a bore 13 in the half-shell 3, which ensures a very short reaction time for temperature regulation.

In the present embodiment, a thermocouple 11 type K is used.

It is also essential to the invention that thermal insulation 14 is arranged around the outer lateral surface 5 of the half-shell 3 and its thickness dimensions correspond approximately to the length of the spacer tube 9 .

As a result, not only a highly precise and very reliable temperature control of the valve spindle housing 2, but also a very heating cost-optimized temperature control of the valve spindle housing 2 is ensured by means of the heating collar 1 according to the invention.

It is also important that the thermocouple 11 is arranged in the spacer tube 9 and in the bore 13 of the half-shell 3 so that it can be replaced. As a result, the thermocouple 11 can also be replaced separately, very easily, quickly and inexpensively, or maintained.

By means of the solution according to the invention, it has thus been possible to develop a heating collar 1 for heating a valve spindle housing 2 in valves used in high-temperature energy technology, which can be installed easily and quickly, but can also be maintained easily, quickly and inexpensively, but which also prevents "freezing". of the valves and which at the same time enables energy-efficient heating of the valve spindle housing 2, is resistant to the salts and acids used in high-temperature energy technology, and which is also even under very extreme conditions, such as daily outside temperature fluctuations in the range from minus 10 °C above the dew point to plus 60 °C, an extremely high humidity, with a heating temperature of the heating jacket of up to a maximum of 750 °C, a highly precise and very reliable temperature control is guaranteed over a long service life, and which are also easy to manufacture in terms of production technology ka nn.

Reference List

1

heating sleeve

2

valve stem housing

3

half shell

4

inner contour

5

lateral surface

6

tubular heater

7

terminal box

8th

mounting tab

9

spacer tube

10

cold end

11

thermocouple

12

measuring point

13

drilling

14

thermal insulation

15

sheathing

16

sprue nozzle

17

through hole

18

clamping screw

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 3428539 A1 [0008, 0009]
• DE 4013538 A1 [0010, 0012, 0013]
• DE 102010021968 A1 [0015, 0016, 0017]

Claims (10)

Electrical heating collar (1) for heating a valve spindle housing (2) in valves used in high-temperature energy technology, with two half-shells (3) made of cast material, which have an inner contour (4) as a contact surface on the inside and an approximately cylindrical outer lateral surface (5) on the outside, wherein in each of the half-shells (3), an originally linear electrical tubular heating element (6) deformed in a meandering manner by bending is cast in such a way that its electrical connection points are arranged in a terminal box (7) for electrical power supply arranged on the heating sleeve (1), characterized - that the two half - shells (3) are completely identical in construction, and - that mounting brackets (8) are arranged in the connection area of the two half-shells (3), - that the inner contour (4) of the half-shells (3) corresponds in size and shape to the Outer contour of the respective valve spindle housing (2) is adapted, and - that on each of the half-shells (3) a separa ter terminal box (7) is arranged for the power supply, and - that a spacer tube (9) is arranged between the half-shell (3) and the terminal box (7) assigned to it, and - that the spacer tube (9) is fixed/rigid in the respective half-shell (3) is anchored, and - that the end regions of the tubular heating element (6) arranged in the spacer tube (9) are designed as cold ends (10) (ie without heating coils), and - that a thermocouple (11) is arranged in the spacer tube (9). , and - that the measuring point (12) of the thermocouple (11) is arranged in a bore (13) in the half-shell (3), and - that around the outer lateral surface (5) of the half-shell (3) a roughly Thickness dimensions of the length of the spacer tube (9) corresponding thermal insulation (14) is arranged. Electrical heating sleeve (1) after claim 1 , characterized in that the cast material of the half-shells (3) consists of the brass alloy CC761S. Electrical heating sleeve (1) after claim 1 and/or 2, characterized in that the tubular heating elements (6) have a casing (15) made of steel. Electrical heating sleeve (1) after claim 3 , characterized in that the material 1.4541 (X6CrNiTi18-10) is used as the casing (15) for the tubular heating element (6). Electric heating jacket (1) according to one of Claims 1 until 4 , characterized in that the spacer tube (9) consists of the material 1.4301 (X5CrNi18-10). Electric heating jacket (1) according to one of Claims 1 until 5 , characterized in that on each of the half-shells (3) a sprue (16) is arranged, in which the spacer tube (9) is cast. Electric heating jacket (1) according to one of Claims 1 until 5 , characterized in that the spacer tube (9) is firmly anchored in an adapter plate (16) brazed to the half-shell (3). Electric heating jacket (1) according to one of Claims 1 until 6 , characterized in that the terminal box (7) is made of stainless steel. Electric heating jacket (1) according to one of Claims 1 until 8th , characterized in that the thermocouple (11) is arranged interchangeably in the spacer tube (9) and in the bore (13) of the half-shell (3). Electric heating jacket (1) according to one of Claims 1 until 9 , characterized in that in the mounting brackets (8) through holes (17) for clamping screws (18) are arranged.

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