DE425711C - Evaporator for refrigeration machines - Google Patents

Description

Evaporators for chillers. They are already zigzagging Doppekohrwärmeaustaus.cher has been proposed in which the connection points the inner pipes and the outer pipes of a double pipe run on opposite sides Pages that are not in accordance with the commonly used scheme in Fig. r, sound like that of Fig. z, uni such a good stiffening of the entire pipe system and easy access to the screw connection points. With heat exchangers. this type of construction does not have a pure countercurrent effect achieve. One of the heat carriers from top to bottom, the other from below directed upwards, countercurrent occurs, in relation to the entire system, but Both heat carriers run in the same way in each of the double pipe strings Direction. If, on the other hand, both heat carriers are routed either upwards or downwards, so they run countercurrently in each individual double pipe string while -related to the whole system direct current effect arises.

The idea of the invention now lies in the knowledge that the use of the type in question with opposite turns of the outer and inner tubes with a very specific directional guidance of the heat transfer medium, namely with guidance both heat carriers from bottom to top - so neither of the two Heat transfer medium from top to bottom -, the use as an evaporator - not as a Condenser - in refrigeration systems offers special advantages that at hand the drawing are explained in more detail.

For an evaporator with normal switching according to the scheme of Fig. I, the relationships are as follows: The one for the refrigerant (ammonia etc :) The advantageous exe path is the one from bottom to top, since the refrigerant is in denser aggregate state enters the evaporator than exits. The reverse leadership would affect the efficiency of the whole thing so unfavorably that - at least in a double tube evaporator - the upward flow of the refrigerant as a given Rule can be considered.

Assuming this upward flow of the refrigerant, now speaks as far as the coolant (brine) is concerned, for its downward flow (countercurrent flow) the advantage of the high relative speed in relation to the refrigerant, As is well known, a great mutual speed is decisive for the heat exchange influenced in a favorable sense. On the other hand, it also has the Line of the refrigerant from bottom to top has an advantage, namely that of the ability the greater hydrostatic pressure entrains air particles into the evaporator is prevented. The routing of the secondary refrigerant also means from bottom to top with such evaporators a saving on tube, in which the coolant after passing through of the inner pipe should also sprinkle the outer pipes from above.

When using the circuit according to Fig. I with an evaporator soot so - definitely one of the three disadvantages: low relative speed, unfavorable guidance of the medium to be evaporated, risk of air penetration into the vaporizer.

On the other hand, it is different when using one set up according to the scheme in Figure 2 Evaporation of the type shown in Fig. 3 with the circuit indicated by arrows the paths of both heat carriers.

First of all, it should be noted that it is only the high relative speed of the two heat transfer media that makes the countercurrent circuit advantageous in an evaporator according to Fig. I. The other for other heat exchangers - such as. B. Condenser - also for the choice of counterflow; speaking circumstance. The fact that the heat exchange is the more favorable, the more even the temperature difference between the primary and secondary heat transfer medium from the inlet to the outlet of this double pipe system, is out of the question for an evaporator, since the evaporating agent during its entire path maintains the same degree of heat through the evaporator. Taking this into account, the following picture results when the refrigerant flowing through the ring-shaped cross-section enclosed by the outer tube a enters at the bottom at lt and exits at the top at f , which the inner tube! The brine flowing through also enters at the bottom at k and exits at the top at g: First, the refrigerant entering at lt retains its path from bottom to top, which is described above as given, and secondly the brine to be cooled is also guided upwards, which, according to the above, is the cheaper one Thirdly, as a look at the path of both heat carriers indicated by arrows in Fig. 3 shows, there is a relative speed between these two heat carriers in each individual double pipe that is just as great as if one were being used Evaporator according to Fig. I pure countercurrent circuit is selected, which, however, would only be possible in connection with other 'disadvantages according to the above. In addition, there are the structural advantages of the pipe system according to Fig. 2.

All in all, when using the D: double pipe system with opposite windings for an evaporator and when using the dex described, in and of itself unusual switching mode of the ways of the heat transfer medium advantages achieved, their entirety via the simple sum of the advantages of the types according to goes beyond Figs. i and 2.

Claims (1)

PATENT CLAIM: Evaporator for refrigeration machines, characterized in that that in the double pipe system known per se, in which the connections of the Outer and Innenrahr.e each lie on opposite sides, and with the therefore the outer and inner pipe veins run in opposite directions (Fig.2), both the refrigerant to be evaporated and the refrigerant (brine) to be cooled by are passed down to the top, whereupon the latter then the outer pipes from above sprinkled down.