DE3022068A1 - Heater esp. for liquefied gases - has coiled tube as secondary winding of electrical transformer and acting as ohmic resistor - Google Patents

Abstract

An appts. for heating liquid or gaseous media, esp. for evaporating liquified gas such as propane, butane and/or mixts. of these, comprises a coiled tube through which the medium flows. This coiled tube (13) is of metal, constitutes an ohmic resistor and is part or the whole of the secondary winding (14) of a transformer. The prim. winding of this transformer (16) is connected to an alternating voltage source and the coiled tube (13) is electrically short circuited at its inlet and outlet ends. Pref. electrical insulation between the prim. and sec. windings has good thermal conductance. Pref. also, there may be an ohmic resistor (28) in series with the primary winding of the transformer This resistor heats the inlet end of the coiled tube. More specifically, this ohmic resistor (28) is wound around the feed line (27) leading into the coiled tube. Used esp. for an evaporator for liquified gas consisting of propane and butane, where the gas must be thermally evaporated to prevent these constituents becoming unbalanced in their proportions.

Description

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. ■ '■■ ?. ^ The present invention relates to a device for-, *

ff · ÄsUwärmen liquid or gaseous media, especially for ^ f

* #. CJtfVaporation of liquid gas, such as propane, butane and / or the like, ■;

£ *% liP ^acn the generic term of claim 1. "? ·

* Since almost all commercially available liquefied gases have more or fewer propane-butane mixtures are used when Gas from containers first the lower-boiling components |

evaporates. As the emptying progresses, the proportion of propane decreases and finally the proportion of butane predominates.

In many cases, the gas in uniform composition _"must; the burners are supplied A typical example is the inert gas system, which is used in the iron industry increasingly apply But many other consumers need composition a constant gas...

In all of these cases it is only possible to use an evaporator to maintain the gas composition, at least one container filling, from the beginning to the end of the withdrawal. §

Smaller capacity evaporators come in certain climates |

also for household heating, kitchen installations, swimming pools Ij

etc. are used. Similar devices can also be used, for example, for |

Lubricating oil preheating for internal combustion engines or also as a preheating

warmer of liquid fuel to be used for burners.

Such devices have been designed so that the from to heating medium flowing through a coil into a heat transfer medium is immersed in a container made by i

For example, an electric heating coil is heated. Disadvantageous ||

what is important here is that the liquid heat transfer medium, such as, for example, |

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Genantin or Glycol has to be serviced and replaced after a long time 'and that the container is corroded and thus damaged after a certain period of time. In addition, this type of device only has indirect heating, namely - ^; by means of the liquid heat exchanger and indirect heat cooling is possible, which in turn results in slow regulation and poor efficiency.

In another known device, a heat exchanger is used for indirect heating of the medium to be heated Aluminum core used in which the coil is cast. Apart from the fact that here, too, the same unfavorable If there are thermal conduction conditions (if not even less favorable), this device is practically exclusively made up of separately manufactured Components produced, so that the device is very expensive overall.

The object of the present invention is therefore to provide a. device to create for heating liquid or gaseous media of the type mentioned, in which these disadvantages are avoided are, with aem there is direct heating of the medium in question, which has a simple, robust structure and which works economically in terms of energy.

In the case of a device of the type mentioned at the outset, this object is achieved by the features specified in the characterizing part of claim 1 solved.

Because the coil in which the medium to be heated is located is designed directly as an ohmic resistor and heats up because a short-circuit current flows through it, this heat is directly transferred to the Transfer medium. This results in a very fast and good heat conduction and the heat losses are to a minimum

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degraded. In addition, the device can essentially consist of Standard parts, because only the secondary winding of the transformer has to be specially manufactured. It is possible that the coil forms the secondary winding as a whole, i.e. over its entire length, i.e. around the primary winding is wound. But it can also be part of the length of the coil outside of the actual transformer lie, so that this part of the indiu; .. erred Subject to voltage and short-circuit current flowing through it is, but is no longer magnetically coupled to the primary winding. In this way, given the primary winding determine the short-circuit voltage and thus the heating power with constant electrical resistance of the pipe coil, without possibly having to use non-standard transformer cores!

In preferred embodiments of the invention The device is also used as heat energy losses for indirect preheating of the medium in question used. For example, the heating of the primary winding is used in this way, in which the electrical insulation between The primary and secondary windings of the transformer have good thermal conductivity and the two windings are connected to one another are shed. Depending on the type of scheme and the type of used electrical control components, it can be useful to limit the peak voltage when switching on the Device to install a resistor in series in front of the primary winding of the transformer. This upstream resistor is then expediently designed so that it has a feed line connected to the inlet end of the coil electrically insulating, but not thermally surrounds in an insulating or thermally conductive manner. Besides, it can be expedient be another part of this connected to the pipe coil supply line with a metal mounting plate, the

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serves as a heat sink for the electronic components of the control, to connect in a thermally conductive manner. In this way too this results in indirect preheating of the medium in question.

The control or regulation of the device according to the invention to achieve and maintain the desired temperature of the pipe coil and thus of the medium to be heated can be carried out, for example, by what is known as phase control. This type r ^ of the control is, however, admitted to operating the device directly to the grid only for a particular service. In a preferred embodiment of the present invention, therefore, a control device according to the characterizing part of claim 8 is used. This type of regulation with vibration packet control is very precise and can also be used, in particular, for. higher powers can easily be expanded in such a way that "the primary winding of the transformer is given one or more intermediate taps into which further triacs are then switched on, which are controlled according to the required power.

Further details and embodiments of the invention can be found in the following description in which the invention based on the example shown in the drawing game is described and explained in more detail. Show it:

1 shows a side view of a device for heating liquid or gaseous media according to a preferred one Embodiment of the present invention,

FIG. 2 shows a side view of the device according to FIG. 1 opposite the side view in FIG. 1, also at removed side wall and in a schematic representation, and

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3 shows a block diagram of the control device of the device according to the invention.

According to FIGS. 1 and 2, the device 11 according to the invention for heating liquid or gaseous media, in particular for evaporating liquid gas such as propane, butane and / or the like. "'-" t ^Λ within an upright, roughly cuboidal structure

'"Housing 12 arranged. The main component of the device 11 is' _f ^ - a pipe coil 13 through which the medium to be heated flows

"'- - and which at least partially the secondary winding 14 of a" ^? J 'transformer 16 forms. Here, the coil 13, which is made of aluminum or copper, that is, an electrical and heat- '; moderately conductive metal, with a shorting clip

'-: provided that connects the input end 18 to the ausgangssei- • ^ ;, _"v> term end 19 of the coil 13 electrically. on

Thus, in the coil 13 because they 'are at least partially short-circuited secondary winding V \ of the transformation -, induces a short-circuit voltage, ^J tors forms 16 at Ge, gebenem Ohm'sehen resistance of the coil 13 has a loading > Correct short-circuit current causes the coil 13 through - C). ' flows and, since it is designed as an ^{ohmic 1} shear resistor, heats up. This thermal energy is transferred directly to the medium to be heated.

For the compact structure of the device 11, the following results in detail from FIGS. 1 and 2: The transformer 16 is fastened with its rectangular laminated core 22 on the housing base 21 in an electrically insulating manner. A primary winding 2 3 and the secondary winding I ¹ + of the transformer 16 that concentrically surrounds it are arranged within the laminated core. Electrical insulation, which has good thermal conductivity, is arranged between the two windings 14 and 23 designed as cylinder coils. For example are the two windings

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14, 2 3 cast in resin. The connections of the primary winding 2 3 are brought out in a known manner. As mentioned, the secondary winding 14 consists of the pipe coil 13, wherein, as can be seen from FIG. 2, the input and output ends 18, 19 on one side of the laminated core 22
are arranged directly next to each other. In the exemplary embodiment, the coil 13 is essentially completely as
Secondary winding 14 is formed, that is to say wound concentrically around the primary winding 2 3 jgf ^, namely in the embodiment of ■ fj! bottom up as a single-layer winding, with the individual S |; "Windings for electrical insulation are kept at a distance from one another J§f |!. The individual turns of the secondary Mip winding 14 can be thermally insulated individually or as a whole as a winding in addition to Up fäußen

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sBefore- ί | in another, not shown embodiment ! I lying invention, only a portion of the coil 13, the * fp "secondary winding 14 of the transformer 16. The other part of the 'Λ coil 13 in this case runs, though immediately adjacent, so * ^ | but outside of the transformer 16, so that it is not influenced magnetically. Nevertheless, the entire coil 13 is from. | % Short-circuit current flowed through, since only its ends 18, 19 are provided with ^ Idem short-circuit clip 17. One achieves with it
compared to the first embodiment, a lower number of turns * of the secondary winding 14 a lower short-circuit voltage and
thus with the same ohmic resistance of the pipe coil 13
because of their same length, a lower short-circuit current. It
however, it is also possible to leave the number of turns unchanged and to increase the length of the pipe coil, so that the short-circuit current also decreases but the effective heat transfer area increases.

At the ends 18, 19 of the coil 13 opposite
Side of the laminated core 22 is a substantially U-shaped
Part 2 6 of a supply line 2 7 for the medium to be heated in

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perpendicular direction parallel to the solenoid 14, 2 3 arranged in their immediate vicinity. The end of the rising area of the U-shaped lead part 2 runs horizontally above the laminated core 2 2 and is on the other side of the laminated core 22 with the input side Enae 18 of the coil 13 connected, for example screwed. The descending area of the U-shaped lead part 26 is from

ii .. ^ ₁ '- a series resistor 2 8, preferably coaxially surrounded, woks V

-; , ''",;" in this case it is electrical compared to the »supply line 27, but 'ii - ·' · = ■, \

'[' ·, F is not thermally insulated. The series resistor 28 is coil-

[j ~, ■ like wound and can, if necessary, by means of an inner Metallj ^ ■, the tube may be formed such that it at the same time as radio

, Interference suppression choke can act. The upper end of the descending j · area of the U-shaped feed line part 26 merges into a feed /, P line part 29, which is initially parallel to the upper leg> · F; of the laminated core 22 runs and then in the vertical direction f *. this one above crosses. On this part 29 is a thermally conductive metallic mounting plate 31, which is firmly connected to this Zuleitungsi part 29 with good thermal conductivity, for example. Is soldered.

ί; On the mounting plate 31, the control device 32 is partly I as a block within a box 24 and partly in the form; individual components 46, 47 attached. This mounting plate X \ J>. thus serves on the one hand to hold the components of the control device 32 and on the other hand as a cooling plate for certain components subject to thermal power losses, such as triacs; Zener diodes, series resistors and the like. In addition, these

Mode the heat from the mentioned components via the mounting plate 31 indirectly to the "medium to be heated" flowing through the supply line part 29.

The supply part 29 is connected at its other end to a solenoid valve 3 3, from which a pipe section is connected, which runs vertically upwards and penetrates a housing cover 34, is screwed to this and a

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Connector 38 has. In a corresponding manner, a line output part 36 is provided, which by means of a screw connection is connected to the cover 34 and has a connecting piece 39 and the other end with the initial one End 19 of the pipe coil 13 is firmly connected, for example. / Is screwed. Parallel to this output part 36 is a Pressure relief valve 37 is provided. *

In the illustrated embodiment of the present invention The ends 18, 19 of the coil 13 are arranged on one side of the laminated core 22. According to a not shown Embodiment, it is also possible that the two ends 18, 19 of the coil 13 on both sides of the vertical Legs of the laminated core 22 are provided. In this case, the ends 18, 19 of the pipe snake 13 are, for example, up to the Laminated core 2 2 pulled up and provided with a longer short-circuit clip, which then lies across the laminated core 22.

In a manner not shown, the device 11 located within the housing is thermally insulated from this, at least as regards the area around the transformer 16 below the honing plate 31.

To the connecting pieces protruding from the housing cover 34 38, 39 on the one hand, for example, a liquid gas tank for supplying the relevant medium or a removal line is connected. Instead of the extraction line, it is also possible to use a buffer to be provided. The pressure relief valve 37 is also passed to the outside through the cover 34.

According to FIG. 3, the control device 32 for regulating the desired temperature on the surface of the pipe coil 13'j or the temperature of the medium to be heated has the following blocks j or components. The secondary and primary windings 14 and 23 of the transformer 16 are shown schematically. J The primary winding 23 has in addition to the two end connections 41 j

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and 42 an intermediate tap 43. The end terminal 41 and the intermediate tap 43 are respectively connected via a controllable - _"Λ ',''- ^ switches, in the exemplary embodiment through a triac 46 and Xs, .147-'I to the one terminal and the End connection 42 to the other "; - / / ^ terminal of a voltage 44, for example the mains voltage. /; \ ·; ^ - /" By means of the two mutually locked triacs 46, 47 "" - either the whole Primary winding 2 3 or only a part _; "of this primary winding 2 3 can be applied to AC mains voltage. The triacs 46, 47 are controlled by means of a control Γ) part or ignition part 48 or 49, which together with a constant

voltage supply circuit 51 of a power supply unit 52 connected to the mains voltage 44 '. The power supply unit 52 also has a DC voltage supply circuit 53 which is galvanically isolated from the supply circuit 51 and which is connected to a temperature regulator part 54. The controller 5 4 is connected to the solenoid valve 3 3 on the one hand and to a temperature sensor 56, in the embodiment in the form of an NTC resistor. This measuring sensor 56 is attached directly to a region of the coil 13, for example near the output-side end 19, in which it is, for example, soldered onto the coil. In addition, the controller 54 is via an optocoupler 5 7 or 5 8 with the control = or ignition part 48 O _or . 49 connected. In this way exists between the regulator

54 and the ignition parts 48, 49 a galvanic separation.

The control or regulation now takes place in such a way that when the device 11 is connected to the mains voltage, the triac 4 7 is activated so that mains voltage is applied to part of the primary winding 2 3, i.e. the maximum power is switched on. Once a certain temperature, for example 40 ^° C., has been reached, the controller 54 controls the solenoid valve 33 so that it opens and the medium to be heated can flow through. If a surface temperature of the pipe coil 13 of, for example, approximately 46 ° C. is reached, the triac 47 is closed (non-conductive) and the triac 46 is activated and thus opened (conductive), see above

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that now the primary winding 2 3 with its full number of turns is applied to the AC mains voltage. In this way the trans-U | j ρ siformator 16 is corresponding to a certain part of the performance; JÖlll! switched to the number of turns ratio. This triac 46 is SIBS1 Ariun off so long and on, as long as a certain i§i | S ^§: | f% will have no 'temperature range of, for example, between 46 ° C and 48 verffl.. In doing so, the desired temperature is maintained by switching the WiSl- I on and off, for example half the power. ψ ^ '- ν /' .^ If, however, the minimum Φφ ΐ 'temperature of 46 ° C, for example, cannot be maintained with this half power, see; is switched back to full rated power by closing the triac 46 and opening the triac 47. In this way, only a certain power difference and not the maximum nominal power is fully switched in each case. The regulator part 54 has the effect that the triacs 46, 47 are locked against one another, so that they never overlap in their open state (conductive state). Since this can occur for at least one half-wave when switching on, possibly because of the voltage peaks, the aforementioned pre-shell twi de rs tand 28 is provided, which is arranged in the supply voltage feed to the primary winding 23. When leaving

f. switch the device Ii to the above-mentioned temperature of 40 C, for example

'fallen below, the controller 54 causes the solenoid valve

33 closes and shuts off the medium supply.

It goes without saying that if the device 11 only has a certain To have maximum power, which can still be switched according to the VDE rules, is also sufficient, just one triac to use and to omit the intermediate tap 43 of the primary winding 2. There is of course no control part, so that the control device 32 becomes simpler as a whole. But it is also possible to subdivide the Make switchable power by providing several intermediate taps on the primary winding 2 3, in which

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In each case a triac is provided for the supply voltage line, each of which is in turn assigned an ignition part. In this. Shape, the control device 32 can be expanded more or less arbitrarily, so that it is always guaranteed that With certain services that are to be switched, only a certain number of switching operations takes place.

As mentioned, the triacs on the mounting plate 31 for f. Dissipation of heat together with other components of the control device 32, in particular the power supply unit are mounted. The other components of the control device 32 are preferably held on circuit boards on this mounting plate 31. It goes without saying that the control device 32 can have an overtemperature protection in a manner not shown.

- End of description -

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Claims (1)

Claims Device for heating liquid or gaseous media, in particular for evaporating liquefied gas, such as propane, butane and / or the like., With at least one of the medium to be heated flowing through heated pipe coil, characterized in that the metal coil (13) shear than Ohm ¹ Resistance is formed and at least partially forms the secondary winding (14) of a transformer (16) directly, to whose primary winding (23) an alternating voltage can be applied, and that the coil (13) in the area of its input and output ends (18, 19) is electrically short-circuited. Ϊ. Device according to Claim 1, characterized in that the electrical insulation between the primary winding (23) and the secondary winding (14) of the transformer (16) is a good heat conductor. 130052/0153 -2- t · Il Ii I SUBMITTED 3. Apparatus according to claim 1 or 2, that
an Ohmic resistor (2 8) connected in series upstream of the primary winding (23) is arranged in such a way that it has the
the input end of the coil (13) influenced by heat. 4. Apparatus according to claim 3, characterized in that the vori ^ lifp§f | Äes ehalte te resistor (28) wound like a coil and a ^ SÄÄÄit the input end of the pipe coil (13) ^ he {% ΡΛ ¹ ! _A Sundene supply line (27, 26) surrounds in an electrically insulating manner. ^ cj 5;: iDevice according to claim 3 or 4, characterized in that || 3i; ^; > |: ^ ' ^tf % er upstream resistor (28) as radio interference suppression q ! if "'"' * '! throttle is designed. _v - SI '' I ^ device according to one of claims 3 to 5, characterized in that it rejects. || -I * ^ ijjdaß the upstream resistor (28) a further part, _t; . ^ ₂ - ^ l ^e - | the supply line (27, 26) is arranged adjacent, and this. | ^ J || ^% ^! Arrangement (26 - 28) is encased by thermal insulation. Ii ~ ^? ■ ΐ "; | 4 | $ ^τ \ · - - ^ ¹ JDevice according to one of the preceding claims, characterized ^d \ / 4 ■.: Ip marked that a thermally highly conductive assembly ■ , | ^ia i "^ plate (31) for the electrical, especially heat loss \\ ! afflicted components (46, 47) of a control device (32) J on one with the inlet end (18) of the coil I, (13) connected supply line (27, 29) is attached in a thermally conductive manner. | f .- ». ν! Device with a control device to achieve τιηά hold
I "the desired temperature of the pipe coil or this ? if 'flowing through the medium, after one of the preceding I claims, characterized in that the control device I; (32) at least one connected to a control part (48, 4-9) Triac (46, 47) in the one AC voltage supply line to the primary winding (2 3) of the transformer (Ib) 130052/0153 ;> ^? Jtf4vi5ff ^ ; j . ^ f ^^^ ^ aK ^ r ^ lift NACHQERESCHT 3022085 and a regulator part (54) which is connected to a temperature sensor, preferably an NTC resistor (56) which is attached directly to one point on the pipe coil (.13) is connected and which is coupled to the control part (48, 49) for the triac (46, 47) glavanisch separated, wherein the control part (48, 49) and the regulator part (54) are each connected to a DC voltage supply part, which DC voltage supply parts (51, 53) are galvanically separated from each other. 9. Apparatus according to claim 8, characterized in that the galvanic separation between Jem control part (48, 49) and the controller part (54) takes place by optocouplers (57, 58). 10. Apparatus according to claim 8 or 9, characterized in that the regulator part (54) is connected to a solenoid valve (33) arranged in the medium supply line (27) and this opens or closes the coil at a certain temperature. 11. Device according to one of the preceding claims, characterized in that the primary winding (2 3) is provided with at least one intermediate tap (43), in the voltage supply line, a triac (47) is provided, which via a further control part (49) with the Controller part (54) is coupled galvanically isolated. 12. Device according to one of the preceding claims, characterized in that the transformer (16) is attached to a base plate (21) of a housing (12), on one side of which a part (26) of the supply line (27) is arranged to run vertically / 'and on the other side of which the output-sextige end (19) of the pipe coil (13) is provided and that directly above the transformer (15) on a horizontal part (29) of the supply line (27) the mounting plate (31) is attached in a thermally conductive manner the housing cover (34) is held at a distance. - End of claims - 130052/0153