DE1233889B - Device for vaporizing and heating a liquefied gas - Google Patents

Description

Device for vaporizing and heating a liquefied gas The invention relates to a device for vaporizing and heating a liquefied Gas with a releasable electrical heating element and a pipe and a heat transfer medium surrounding these parts. existing heat exchange block, the pipeline having a connection to the storage container for the liquid gas and has an outlet end for the withdrawal of the gas.

When using liquefied gases, a major problem arises when very large quantities of this gas are required in relatively short periods of time. As a result of the evaporation of the gas, which is necessary in this case, a very considerable amount of heat is consumed, which leads to a recooling of the gas and thus to a restriction of the evaporation. In order to avoid this recooling when large quantities of liquefied gas evaporate, it is known to supply the heat of evaporation to the gas from the outside. The heat exchangers used for this purpose should not only have a very high heat transfer capacity, but must also withstand a correspondingly high pressure, since the heat supply in the high-pressure part, i. H. must be done before reducing to the consumption pressure. In order to achieve the best possible heat transfer from the heat source to the liquid gas, it is known to embed the heat source and the pipeline for the gas to be heated in a liquid heat exchange medium. The apparatuses used are, however, designed for the individual case and are relatively complicated.

It is also known to use the medium to be heated for heat transfer to embed in a metal pot, in which at the same time in a corresponding hole an electrical heating element is plugged in. The heat transfer, ung the metal block is in itself very good, but there are certain difficulties due to irregularities during the transfer from the heating element inserted into the bore into the metal block. Because there is no direct connection between the heating element and the metal block, a very high heat gradient is required between the heating element and the metal block, the heat transfer also depends on the condition of the metal surface in the bore for the heating element, machining tolerances and other possible variations is.

In addition, these known arrangements all only work for very specific ones operating conditions estimated in the construction and it must be for different Operating conditions different complete units are produced in each case. In addition, this may arise when the lines for the heat transfer medium are embedded and the gas to be heated in a metal block difficulties, e.g. B. when pouring of the lines due to the different sensitivity to temperatures, Shrinkage of metals and other things.

It is the object underlying the invention, such an apparatus for vaporizing and warming to provide a liquefied gas, in which both the heating elements as well as the C "te gas INTR-en completely in the metal are embedded for the verflüssio tight so that exactly controllable, pre-calculable heat transfer values can be achieved and adaptation to different required heat transfer capacities is also possible without significant structural changes.

According to the invention this is achieved in that the heat transfer medium is made of metal in a manner known per se and the heat exchange block consists of individual elements plate-shaped block parts is constructed, either the pipelines or the Contain heating element and which are clamped against each other with their end faces, wherein the one middle block part or several middle block parts the heating element or contain the heating elements and the pipelines in the corresponding block parts are connected to each other.

This inventive design, the heating elements on the one hand and the pipelines for the liquefied gas on the other hand in different metal blocks embedded, each in the most favorable conditions for the associated line manufacturable are, the whole device according to the modular system constructed and made according to the desired total heat transfer capacity a predetermined number of plate-shaped block parts of both groups can be assembled is. In the case of completely planar training that can be achieved with relatively simple means the contact surfaces of the block parts is a very good, precisely predictable Heat transfer between the individual block parts given.

m in the connecting line between the pipelines in the individual block parts of a pressure-reducing valve can be provided, so that a pre-heating of the liquefied gas in a block, while in the lie-Clenden behind the pressure reducing valve other block part of the occurring during the relaxation heat loss is compensated. With this arrangement, the supply of heat in the high-pressure part and thus the pressure load can be kept low.

A chamber can be located in the connecting line in front of the pressure reducing valve be arranged, which by a when exceeding a predetermined pressure destructible disc or membrane and / or a safety valve with the ambient air communicates. This can cause overheating of the liquefied gas before Pressure reducing valve occurring overpressure can be eliminated and damage of the pressure reducing valve can be avoided. This arrangement of the safety valve in front of the pressure reducing valve, it is possible to switch off the heat supply without risk to increase the maximum possible limit. As a further backup, in the heating circuit a fuse which is responsive to the temperature of the heat exchanger block is provided be.

Since the heat given off to the liquefied gas has only one function the temperature of the exchange block is, by means of this further, very precise protection allows maximum utilization of the device for heat transfer.

The invention is explained in more detail below with reference to the drawing figures using an exemplary embodiment. In the drawings, F i g. 1 shows an oblique view of a device according to the invention for vaporizing and heating a liquefied gas, FIG. 2 in an oblique view schematically the arrangement of three plate-shaped block parts, FIG . 3 is a circuit diagram of the electrical part of the circuit shown in FIG. 1 and FIG. 4 is a circuit diagram showing the connection of the device according to the invention in operation - CSCD. In the exemplary embodiment, the heat exchanger block consists of three block parts 10, 11 and 12 made of aluminum or another metal. The block parts 10, 11 and 12 are firmly clamped against one another by screws 13 which are guided through sprues 14 on the two outer block parts 10 and 12. One or more electrical heating elements are cast in the middle block part 11 , the connecting terminals 15 of which are shown in FIG. 2 are shown. A high-pressure steel pipeline 16 is cast into the block parts 10 and 12. The steel pipeline is, as Pstrichelt in the Fig . 2, in the form of an elongated pipe coil in the block parts and C has an inlet end 17 and an outlet end 18 which is connected to a small chamber 19 . This chamber 19 contains a membrane in a housing 20, which at a predetermined pressure, for. B. 120 atm, is destroyed. In the block part 12, a low-pressure pipeline is also cast in the form of a flat pipe coil, which has an inlet end 21 and an outlet end 22. The inlet end 21 is connected to the low pressure side of an adjustable pressure reducing valve 23, with the high pressure measuring device 24 and the low pressure measuring device 25 . The high pressure side of the valve 23 is connected to the chamber 19 of the housing 20, in which the destructible membrane is located, and thus to the outlet end 18 of the high pressure line 16 .

The whole heat exchanger block is tightly enclosed by a housing 26 in which it is in a thermal insulation 27, for. B. made of glass wool - is packaged. In the housing 26 , a wall 28 is inserted through which connections 29 for the heating element, the inlet end 17 and the outlet end 18 of the high pressure pipeline 16 extend, the inlet end being covered with an insulating sleeve 31 and provided with a threaded pipe connection 32 , while the outlet end 18 of the pipeline 16 leads into the chamber 19 .

A connection block 30 is provided on the wall 28. The chamber 19 and the pressure reducing valve 23 lie outside the housing 26 on its upper side. Also on the top of the housing 26 is a threaded pipe connection 33 which is connected to the outlet end 22 of the low pressure pipeline. The block part 12 is provided with two bores 34, 35 into which temperature sensors 36, 37 of an adjustable thermostat 38 and a fuse 39 can be inserted.

The pressure reducing valve 23 can be provided with a relief valve 40. The chamber 19 can have a spring-loaded safety valve 42.

The inlet end of the low pressure pipeline is connected to the pressure reducing valve 23 via a pressure hose 43 having a reinforcement.

The device operates as follows: for example, liquid carbon dioxide is supplied to the device from one or a series of steel cylinders 45 ( Fig. 4) at room temperature and a pressure - usually in the range of 70 atmospheres. As it passes through the high pressure stage (pipe 16) , the liquid is evaporated. After passing through the pressure reduction valve 23 the vaporous medium reaches the low pressure stage in which it is brought to a desired temperature before it out of the - pipe fitting 33 is delivered to the consumer. To reduce or suppress the evaporation in the steel bottles 45, these are equipped with siphon pipes 46, whereby the temperature and pressure of the bottle contents are kept essentially constant during its delivery.

The temperature of the heat exchange block and thus the temperature of the gas delivered from the threaded pipe connection 33 is controlled as a function of the adjustable thermostat 38 , which is used in the circuit for the electrical heating elements 41 according to FIG. 3 is arranged.

The fuse 39 for protecting the heating elements in the circuit can for example consist of a tin wire. The fuse 39 is preferably double-pole and serves as a fuse in the event that the thermostat 38 is not correctly set in the circuit or fails at all. According to FIG. 3 , a relay 47 with contacts 48 is arranged in the circuit, via which the thermostat 38 controls the heating elements 41. An indicator lamp, e.g. B. a small neon indicator lamp 44 with protective resistor, can also be in the main circuit of FIG . 3 can be used.

The vaporizer can also be used for vaporizing liquid carbon dioxide, which has a low pressure, at subzero temperatures.

Claims (2)

Claims: 1. Device for vaporizing and heating a liquefied gas with a heat exchange block consisting of a controllable electrical heating element and a pipe and a heat transfer medium surrounding these parts, the pipe having a connection to the storage container for the liquefied gas and an outlet end for the removal of the Has gas, characterized in that the heat transfer medium consists of metal in a manner known per se and the heat exchange block is constructed from individual plate-shaped block parts (10, 11, 12) which contain either the pipes (16) or the heating element (41) and which are clamped with their end faces against each other, wherein the one middle block part (11) or several middle block parts contain the heating element or the heating elements and the pipes (16 ) are connected to one another in the corresponding block parts (10, 12). 2. Device according to spoke 1, characterized in that a Drucknünder valve (23) is provided in the connecting line between the pipeline in the corresponding block parts (10, 12). 3. Device according spoke 2, characterized in that a chamber (19) is arranged in the connecting line upstream of the pressure reducing valve (23) , which by a destructible when a predetermined pressure is exceeded disc or membrane and / or a safety valve (42) with the Ambient air is in communication. 4. Device according to one of claims 1 to 3, characterized in that a fuse (39) which is responsive to the temperature of the heat exchange block is provided in the heating circuit. Considered publications: German Auslegeschriften Nr. 1001298, 1030480.