An Improved Method of Disinfection.
Year: 1895

page_text: Date of Application, 3rd Dec., 1895--Accepted, 23rd May, 1896
COMPLETE SPECIFICATION.
An Improved Method of Disinfection.
I, DAVID SJÖSTRÖM, of 9 Vesterlånggatan, Stockholm, in the Kingdom of
Sweden, Notary, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
Heretofore in the disinfection of articles in a heating-chamber it has been usual
to subject the articles either to a dry heat, raising their temperature to more
than 100° C., or to the action of steam. Both these methods possess the dis-
advantage that the articles treated are liable to become damaged or to be
insufficiently disinfected, provided they are composed of materials which are
susceptible to injury from the effects of great heat or dampness, as is the case, with
furniture, furs, leather articles, wearing apparel and the like.
For the disinfection of rooms it has been customary to use certain gases,
especially chlorine, bromine, formaldehyde or the milder disinfectants, sulphurous
acid and gaseous ammonia, which, however, either are more or less destructive to
the articles treated or, as they are now employed, are materially deficient in their
power to penetrate into the interior of the objects, which property is essential to a
good result. All the gases mentioned, as well as others of similar disinfecting
qualities, which in comparison to the steam may be considered as dry gases because
their point of condensation lies below the ordinary temperature of the air, may,
however, under certain conditions be employed to advantage for disinfecting
purposes, a method of accomplishing this end being the object of the present
invention.
The method referred to consists in allowing such gases to act upon the articles
to be treated in a disinfecting chamber or a room which is heated to a temperature
below that commonly used in disinfecting apparatus but above the ordinary
temperature of dwelling rooms. Owing to diffusion of the gases and the air
contained in the pores of the objects, the gases are consequently caused to
penetrate into the latter at a velocity which increases with the rise of the tem-
perature. Another advantage of the application of heat is derived from the known
fact that the disinfecting power of a substance is increased as the temperature
rises. As the action of the gases mentioned is made more powerful by the
application of heat, it is evident that by this means it will be possible to reduce
the quantity of gas or mixture of gases required for the disinfection in the same
ratio as the temperature of the heating chamber or the room is raised, which is a
matter of importance both from an economical point of view and because a means
is hereby provided to reduce the injurious effects of the gases on the articles
treated, experience having proved that these injurious effects are rather to be
traced to the quantity of gas employed than the temperature of the latter.
For the reasons given it is apparent that a satisfactory disinfection will he
accomplished in this manner with a smaller quantity of gas and by heating to a
lower degree than is necessary when these two means are employed separately the
articles treated being at the same time less liable to become damaged than would
otherwise be the case.
The method described, moreover possesses the important advantage that it
enables the operator to adapt the gases and the degree of temperature in the
heating chamber or in the room to the nature of the objects to be treated, which
is a matter of great moment inasmuch as different articles require different

page_text: treatment. It is very advantageous to cause the gas or mixture of gases introduced
to be agitated by means of some mechanism in a known manner, as the gas or gases
will theu more easily penetrate into the objects.
According to the present invention the disinfection is accomplished by the use of
gases only, but instead of using them at the temperature commonly employed their
disinfecting power is increased by heating them to a temperature above 20° C. but
below 1000 C., the degree of heating in every special case being dependent upon
the nature of the article to be treated. Thus if the article does not become
damaged by a higher temperature, the heating may be increased to 80° or 90° C.
but on the other hand the heating may be less if the article is more liable to be
damaged by a higher temperature. In no case however is the heating increased
to 100° C., because most articles become damaged when subjected to such a high
temperature. The temperature commonly used in disinfecting in a disinfecting
chamber according to this invention is 50° to 90° C. (50 to 60° C. for furs, 80°
to 90° C. for bed-clothes and 65° to 75° C. for furniture), but the limits between
which the temperature may be varied are the ordinary dwelling, room temperature
(18° or 20° C.) and 95°C.
Of course such a process will enable the operator to adapt the temperature in
the heating chamber or room to the nature of the articles to be treated, because
the operator has only to heat this chamber or room to 40°, 50°, 60° or 90° or in
general to a temperature at which the article is not damaged, the disinfecting
taking place on account of the increased disinfecting power of the gases by heating.
A temperature of 100° C. is never required, because a complete disinfection with
the gases takes place below that temperature. By using a greater quantity of gas
the degree of heating may be a smaller, which is an advantage, if the objects to be
treated are liable to be damaged by a higher temperature (for instance 80° or 90°
for furs) and on the other hand by using a greater degree of heating the quantity
of gas used may
be a smaller, which is an advantage, if the articles are liable to be
damaged by the gas.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
An improved method of disinfection consisting in the introduction into or
evolving in the heating chamber or the room, where the disinfection is to take
place, of such gases, which possess the power of acting as disinfectants at tem-
peratures below 100° C. and simultaneously heating said chamber or room to a
temperatures below the point mentioned, in order to permit a reduction in the
quantity of gas or vapour usually employed as well as of the degree of heating and
thus avoid damage to the articles treated.
Dated this 3rd day of December 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.