Devices for cleaning heating batteries

In batteries of tubes conducting a heating fluid air is led through the spaces between the tubes, to be heated for use in grain drying installations or the like. Airborne dust and impurities form deposits on the tubes and impair heat transmission. The deposits are removed from the tubes by increasing at intervals the air velocity by means of a grid structure defining passages having a reduced flow area and placed in front of the interspaces between the tubes.

The present invention relates to apparatus for cleaning heating batteries 
which are designed for the throughflow of air to be heated between tubes 
conducting a heating fluid. 
In such heating batteries the velocity of the airflow is kept low when the 
air shall be heated to a high temperature. Dust and other impurities 
entrained with the air will settle on the tubes at the low air velocity, 
and this will reduce the heat exchange efficiency of the battery. 
The removal of the dust deposits will require frequent cleaning of the 
tubes, e.g. blowing by air or rinsing by water. This is a tedious, 
time-consuming and costly procedure. 
It is an object of the invention, therefore, to provide apparatus by which 
the cleaning of heating batteries can be carried out in a very simple and 
efficient manner, eliminating the need of the older non-satisfactory 
methods. 
This object is attained by providing flow accelerating means which can 
selectively be located at and removed from the upstream side of the 
heating tubes, said flow accelerating means defining flow passages 
corresponding to the interspaces between the heating tubes and converging 
to a smaller throughflow area than said interspaces. 
With this arrangement the velocity of the air flow will be raised to a 
level effective for cleaning the tubes when bringing the device in front 
of the tube battery.

In the drawing numeral 1 denotes a battery of finned tubes 2 for conducting 
a heating fluid therethrough. The battery may comprise one or more rows of 
tubes beyond the single row illustrated. Between the tubes 2 passages or 
spaces 3 are defined for the throughflow of air to be heated. The air is 
aspired through these interspaces by non-illustrated fan means of any 
known or suitable type. Dust and other impurities suspended in the air 
will form deposits on the tubes 2 at the low airflow velocity maintained 
for heating the air to the desired temperature. The deposits will act as 
an obstruction to the transmission of heat and will thus impair the 
heating efficiency. In order to increase the air flow velocity between the 
tubes to perform a scavenging action and the removal of the deposits from 
the tubes without the need of providing fans having a large reserve of 
power the invention provides means for accelerating the air flow and thus 
increasing its velocity before its passage between the finned tubes, by 
means of a special choking device. This device comprises an assembly of 
choking members 4 connected by side members 5 and being of dimensions and 
spacing substantially corresponding to that of the tubes 2. Between the 
choking members 4 flow passages 6 are defined having an area susceptible 
to raise the velocity of the air flow passing between the tubes 2 of the 
battery to a magnitude sufficient for cleaning, this area being 
substantially smaller than the free through-flow area between the tubes. 
The device can be moved from an inactive position, for example an elevated 
position as illustrated in the drawing, into a position facing the tubes 
as shown with dash lines in FIG. 2. In the lastmentioned position the air 
is conducted in the first place through the passages 6 and will be 
accelerated thereby to a greater velocity corresponding to the reduced 
throughflow area before it sweeps over the tubes 2. The swift air flow 
will remove the deposits formed at the tubes by air having flown through 
at normal operation velocity. 
In order to keep down flow losses and turbulence of the air passing through 
the choking device the latter is formed with convergent inlet sections 6' 
which are continued by the passages 6. The choking elements 4 are 
preferably formed of profiled tubes or of sheet metal profiles bent to a 
corresponding cross section shape. The frame and grid structure formed of 
elements 4 and the side members 5 is joined together for example by 
welding. 
The device 4, 5 can be arranged for being raised and lowered, for example 
by a mechanism operated by an electric motor. This mechanism can be 
actuated according to a programme, to move the device into or away from 
its operative position with predetermined intervals. 
Beyond the advantageous effects attained with the invention such as 
cleaning easily performed and maintaining the efficiency of heating 
batteries there will also be a substantial saving of energy since the 
heating assemblies and other parts of an installation may remain at 
operational temperature all the time and need not be shut down for 
cleaning which would be conducive to their cooling and the need of 
reheating.