The present invention refers to an instantaneous accumulating steam generator.
It is known that, in prior art instantaneous steam generators, unbalance conditions occur between steam consumption and steam generation inside the steam chamber.
This is due to the chamber internal volume and to the internal pressure decrease range that brings about an increase in water level, thus decreasing the steam volume.
Moreover, the flange surface allows a humidity entrainment due to the pressure decrease occurring during the steam flow from steam chamber to solenoid valve.
Resistances usually have poor wear resistance due both to the high temperature and to the reduced water volume created by the pressure decrease range.
GB-A-623 154, which represents the closest prior art, discloses an accumulating steam generator as described in the preamble of Claim 1.
Object of the present invention is to overcome said drawbacks by providing a steam generator of the above-mentioned type in which the amount of produced steam and the amount of required steam are balanced, without creating a strong condensate entrainment and without excessively stressing the resistances.
A further object of the steam generator according to the invention is to avoid false level signals on the internal probe, due to condensate deposit formation on the probe after the entrainment occurring on the flange.
These and further objects together with other features and advantages, are attained by the instantaneous steam generator of the invention, as claimed in Claim 1.
Further characteristics and advantages of the invention will appear from the following detailed description of an embodiment thereof, given as a non-limiting example, with reference to the accompanying drawings, in which:
As clearly shown in the Figures, the steam generator of the invention comprises substantially a small boiler 1 to which a cover 5 is sealingly fixed in 3; this cover 5 is usually plane and is secured in place by a plurality of through bolts 7 extending through said cover 5 and a suitable circular projection 9 provided on the outside cylindrical wall of the boiler 1.
Centrally to the cover 5, a central, funnelled steam conveyor 11 is provided, from the inside to the outside of the steam chamber 13, designed in such a way as to gently draw steam from inside said steam chamber 13.
For that purpose, said conveyor 11 is of a winding shape, with neck 15 in the Venturi-like tube (see Fig. 3), said neck being adapted so as to facilitate and speed up the steam flow from the boiler 1 to a vessel 17 located downstream.
Said vessel 17 is provided outside the generator boiler 1, and it is centrally located with respect to the conveyor 11, and operates as steam "plenum chamber".
The steam enters said vessel 17 through an inlet conveyor 19, also equipped with neck 21 in the Venturi-like tube, said inlet conveyor 19 being aligned with the outlet conveyor 11 from the boiler 1 and completing the function of softening for the steam flow from said boiler 1 to said vessel 17.
The steam will be sent to users through an outlet hole 21, provided in the Figure on top of the vessel 17, and also equipped with funnelled mouth.
The probe 23 inside the boiler 1 is equipped with a protection chamber 25 for protecting the stem 27 of said probe 23 from condensate deposit formation caused by the pressure decrease occurring on the flange lower surface as well as from false water level signals, caused by the displacement of said water volume by pressure decrease.
The resistances 29, with which the boiler 1 is equipped, are provided at a very long distance between end portion 31 thereof and flange 5, in order to avoid those strong, sudden changes of temperature to which usual resistances are subject.
As for the rest, the resistances 29 are of the same type so far used in these steam generators.