The pipeline networks used to get the energy carrier to the place of use during the supply of gas to the population and industry consist of separate network sections that have different pressure conditions. In order to implement the transfer from one pressure step to another during gas transportation so-called"gas transfer stations"are used. Such facilities contain different pressure reducing units and valves that make it possible to reduce the pressure of gas of a higher pressure-also involving a reduction in temperature.

During the operation of gas transfer stations, especially during the cold winter period it may occur that in the case of a low environmental temperature the gas cooling on its reduction in pressure freezes the condensation precipitating in the pipeline. This frozen liquid may cause operation problems, and, in more serious cases, faults in the technical equipment and damage.

In order to overcome the mentioned deficiency, before the pressure reduction the high- pressure gas is preheated in a heat exchanger established for this purpose, so that after its pressure is reduced, the temperature of the gas remains above the critical value. A chamber hot air heater serving to heat up gases is also described in, e. g, patent description registered under number HU 206.745.

The disadvantage, however, of the solutions used at gas transfer stations is that due to the method of heating, in the interest of satisfying the safety engineering prescriptions, the heat exchanger device has to be positioned separately from the building part that contains the valve structures and the regulation units, at a determined distance, or a special method of construction has to be applied.

Another disadvantage is that the energy supply to the device serving to produce the heat used for the heating of the gas and the transportation of the heating medium require further supplementary elements, the construction of which increases the investment costs further.

Another unfavourable aspect is that transporting the high pressure gas to be warmed to the heat exchanger and returning the now heated gas requires further components the inspection and maintenance of which is essential for the appropriate operation of the station, so again resulting in an investment and operation cost increase.

Our aim with the construction according to the invention was to overcome the deficiencies of the known versions and to create a set of equipment that would make it possible to heat up the high pressure gas to the appropriate temperature-also taking into consideration the accident prevention and safety aspects and prescriptions-in the structure that also contains the regulating valve units and the pressure reducing unit or-without requiring a safety distance- integrated into its immediate environment.

The recognition that led to the arrangement according to the invention was that if, in a novel way, we build a catalytic infrared radiant heater into the heat transfer part-unit so that the feed head of the heat transfer part-unit is directly connected to the lower pressure gas pipeline, while the part of the high pressure gas pipeline that is in the heating unit is formed taking into consideration the heat radiating body of the heat transfer part-unit, then the task may be solved.

In accordance with the set aim the set of equipment according to the invention for the operation of gas-pressure reducing stations-which contains at least one input connection and output connection connected to the gas pipeline, and, furthermore, one or more valve structures arranged between the input connection and the output connection, as well as a heating unit, the heating unit has a housing surrounding at least part of the heat exchanger space of the heating unit, a primary gas duct leading through the heat exchanger space of the housing, and a heat transfer part-unit also placed in the heat exchange space-is constructed in such a way that the primary gas duct is connected to the high pressure section of the gas pipeline, the heat transfer part-unit contains the supply pipe connected to the low pressure section of the gas pipeline, the feed head connected to the free end of the supply pipe, and the radiant heater body placed near the feed head, the radiant heater body has a radiating surface, a reaction part-unit placed along the radiating surface, and a preheating element fitted into the reaction part-unit, and the radiating surface of the radiant heater body is positioned in the vicinity of the primary gas duct.

A further criterion of the set of equipment according to the invention may be that the radiant heater body is a catalytic infrared radiant heater.

A favourable aspect from the point of view of the constructed form is if the primary gas duct is a set of pipes set up of longitudinal pipe members connected allowing high pressure gas flow and transfer pipe members connected to the longitudinal pipe members at an angle between 1-90°. The set of pipes forming the primary gas duct is arranged along the radiating surface of the radiant heater body.

In another version of the set of equipment the primary gas duct is at least partly surrounded by an intermediate heat transfer unit containing a heat-transfer medium, and the radiating surface is positioned along the intermediate heat transfer unit.

In a further different set up of the invention the reaction part-unit is a catalysing blanket containing platinum material. The heat transfer part-unit is supplemented with a filter unit fitted into the supply pipe.

In a further realisation of the set of equipment the heat transfer part-unit contains a gas amount regulator part-unit fitted into the supply pipe, and the gas amount regulator part-unit is linked to the temperature sensor element positioned near the reaction part unit.

In a still further construction of the invention the preheating element is an electrical glowing body.

The set of equipment according to the invention has numerous advantageous characteristics.

The most important of these is that due to the use of the modern heat transfer part-unit it is possible to position the heating unit in the immediate vicinity of the valve structure and the pressure reducing unit, so the dimensions of the gas transfer station are significantly reduced, which does not just moderate the investment costs, but also makes inspection and maintenance simpler.

Another feature that is to be seen as an advantage is that the essential components of the set of equipment can be installed in a concentrated place, so the protection of the elements of the equipment against external effects can be solved in a simpler manner.

Due to the form and position of the novel heating unit the amount of heat loss during the heating of the high pressure gas is reduced to a great degree and with this so is the amount of gas used for the heating.

Another favourable aspect is that the heating unit can be simply and safely regulated, flame formation is excluded, so the solution is more reliable than the known solutions from the aspects of prevention of accidents and safety.

The construction according to the invention is given in detail in the following in connection with construction examples on the basis of diagrams. On the drawing Figure 1 is the outline picture of a version of the set of equipment according to the invention, Figure 2 is a sketch of another set up of the set of equipment.

On figure 1 there is a possible version of the set of equipment 20 according to the invention. It can be observed that the set of equipment 20 is fitted to the high pressure section 11 of the gas pipeline 10 in such a way that the high pressure section 11 of the gas pipeline 10 is connected to the input connector 21 of the set of equipment 20 and the output connector 24 of the set of equipment 20. In the construction version shown the pre-pressure reduction heating of the transported high pressure gas takes place between the input connector 21 and the output connector 24 of the set of equipment 20.

Within the set of equipment 20 one of the valve structures 22 is positioned near to the input connector 21, while another valve structure 22 can be found beside the output connector. The pipe section between the two valve structures 22 includes the heating unit 40. In the case of the present version the pressure-reducing unit 23 is connected to the output connector 24 of the high pressure section 11 of the gas pipeline 10, and the output of the pressure-reducing unit 23 is now connected to the low-pressure section of the gas pipeline 10.

On figure 1 it can be clearly seen that the heating unit 40 is physically in the same place as the other elements of the set of equipment 20, in the immediate vicinity of them and integrated with them. A part of the heating unit 40 is the housing 41, which includes in itself the heat exchanger space 42. In the heat exchanger space 42 there is the primary gas duct fitted in the high pressure section 11 of the gas pipeline 10, as is, furthermore, the heat transfer part-unit 50 serving to heat the primary gas duct 43.

The primary gas duct 43-in the present version-is a set of pipes set up of longitudinal pipe members 43 a and transfer pipe members 43b. The angle"a"between the longitudinal pipe members 43a and the transfer pipe members 43b here is 90°. However, we have to make a remark that this is not a requirement, the angle"a"between the longitudinal pipe members 43a and the transfer pipe members 43b may differ from this. From the point of view of production technology, however, the solution shown on figure 1 is by all means favourable.

The basic requirement of the primary gas duct 43 is, however, that its geometric structure and size should make as good use as possible of the amount of heat being radiated from the radiating surface 53 a of the radiant heater body 53 of the heat transfer part-unit 50 in warming up the gas flowing through the primary gas duct 43 of the high pressure gas pipeline 10.

The radiant heater body 53 of the heat transfer part-unit 50, beside the radiating surface 53a, also contains the reaction part-unit 53b, which in this case is a catalysing blanket containing platinum material. The radiant heater body 53 is a catalytic infrared radiant heater unit. The feed head 52 positioned at the free end 51a of the supply pipe 51 connected to and led back from the low pressure section 30 of the gas pipeline 10 is connected to the reaction part-unit 53b of the radiant heater body 53, as is the preheating element 53c.

Also positioned in the vicinity of the reaction part-unit 53b of the radiant heater body 53 is the temperature sensor element 56, which is linked to the gas amount regulator part-unit 55 fitted to the supply pipe 51. Also fitted in the supply pipe 51 is the filter unit 54, the task of which is to filter out the contamination transported by the gas flowing in the low pressure section 30 of the pipeline 10 into the supply pipe 51 before the gas amount regulator part-unit 55 and the feed head 52.

During the operation of the construction according to figure 1 following the reduction of the environmental temperature to under the given value on the instruction of the central unit-not shown on figure 1-the preheating element 53 c switches on, which in this case is an electric glowing body working on the resistance principle. The preheating element 53c heats up the reaction part-unit 53b of the radiant heater body 53 of the heat transfer part-unit 50 to the appropriate degree. After heating up to the operating temperature the low-pressure gas arriving on the supply pipe 51 from the feed head 52 reacts on the catalytic blanket and heat is produced. The heat produced gets to the longitudinal pipe members 43 a and the transfer pipe members 43b of the primary gas duct 43 through the radiating surface 53a, as a result of which the primary gas duct 43 is heated up and also heats the high pressure gas flowing in it, which in this way, after going through the pressure reducing unit 23, does not cool to a temperature lower than that desired.

The temperature sensor element 56 and the gas amount regulator part-unit 55 connected to it make sure that the temperature of the radiating surface 53 a of the radiant heater body is nearly constant. Depending in the temperature of the radiant heater body 53 the temperature sensor element 56 sends a signal to the gas amount regulator part-unit 55, which either reduces or increases the amount of gas reaching the feed head 52, with this changing the intensity of the process taking place in the reaction part-unit 53b and through this the heat production.

In figure 2 a detail of a heating unit 40 can be seen in which the primary gas duct 43 connected to the input connector 21 is positioned in an intermediate heat-transferring unit 60 containing a heat-transfer medium 61. In this case the heat-transfer medium 61 is soft water, but it may also be a liquid with appropriate heat transmitting properties, even possibly gas, too. The radiant heater body 53 is positioned along the intermediate heat-transferring unit 60 and the radiating surface 53a of the radiant heater body 53 is directed at the intermediate heat- transferring unit 60. The form of the radiating surface 53a should practically follow the geometric form of the intermediate heat-transferring unit 60.

Here we need to make the remark that the radiating surface 53a of the radiant heater body 53 may partly or completely enclose the primary gas duct 43 or the intermediate heat-transferring unit 60. In the case of the version shown on figure 1 an alternative solution in order to improve the efficiency of heating is that heat reflecting elements-not shown on the diagram -are positioned near to the primary gas duct 43 opposite to the radiating surface 53a, so any possible heat loss is also used.

It is also obvious that the pressure-reducing unit 23 may be integrated into the set of equipment and so the complete gas transfer station may be constructed as a single module.

The set of equipment according to the invention may be used at gas transfer stations to good effect where it is practical to heat up the gas before the pressure of the high-pressure gas is reduced.

List of references 10 gas pipeline 11 high pressure section 20 set of equipment 21 input connector 22 valve structures 23 pressure reducing unit 24 output connector 30 low-pressure section 40 heating unit 41 housing 42 heat exchanger space 43 primary gas duct 43a longitudinal pipe member 43b transfer pipe member 50 heat transfer part-unit 51 supply pipe 5 la free end 52 feed head 53 radiant heater body 53a radiating surface 53b reaction part-unit 53c preheating element 54 filter unit 55 gas amount regulator part-unit 56 temperature sensor element 60 heat transferring unit 61 heat-transfer medium "a"angle