Apparatus For Permeating An Auditorium With Odours In Conjunction With Projection Of A Motion Picture Film

Abstract

A method and apparatus for introducing controlled amounts of odors into an auditorium generally in conjunction with, for example, a visual presentation. Cartridges or other receptacles containing odorous substances can be made to communicate with an air injection duct in correspondence to markings on, for example, a film strip. A secondary air feed system is capable of evacuating the odorous substance below the sensing threshold. Appropriate valve means and ducts along with injection nozzles are provided and controlled for introducing the odor.

Description

The present invention relates to a method for permeating an auditorium with odours.

It is known to spread odours in an auditorium by manually spraying liquid odours substances in an atomized form.

It is also known to employ cartridges or other receptacles containing odorous substances of different kinds which, as selected, e.g., controlled by markings on a film strip, can be made to communicate with an air injection duct for spreading the desired odour at the wanted moment in the auditorium.

However, no method is known whereby it is possible to fully undertake a controlled spreading of odours in an auditorium in such a way that the odour is produced and removed at will and so that it is possible to supply successively, and at will different odours without that these have a deleterious effect upon each other.

The difficulties do not consist in introducing the odour into the auditorium but, on the contrary, to remove it again, and only if it is possible to achieve an almost immediate removal of the odour is it possible to achieve a truly controlled diffusion of the odour in the auditorium.

This can be achieved by means of the method according to the present invention which is characteristic in that the auditorium is ventilated with fresh air at an air renewal frequency of at least 20 times per hour, preferably at least 30 times per hour, and in that via a separate air feed system an odorous substance having a low adsorbability viz. introduced in a dose which, by means of the ventilation, results in a concentration in the zone of the auditorium occupied by the audience that exceeds the sensing threshold value in the auditorium for the odorous substance in question, but is so low, that after two air renewal periods at the most have elapsed, the concentration lies below the threshold value.

In order to obtain a desired concentration of the odorous substance in the auditorium, or rather, in the volume of air which at the given moment passes at the level of the noses of the audience, the volume of the odorous substance supplied during a given space of time has to be included in the volume of air introduced into the auditorium within the same space of time. This volume of air is composed of the fresh air supplied with which the auditorium is being ventilated and the air introduced via the separate air feed system. Moreover, when fixing the concentration, regard will have to be paid to the rarefaction taking place in the course of the movement of the air from the point of injection to the zone of the auditorium occupied by the audience.

The volume of air introduced via the separate air feed system constitutes only a fraction of the total air volume, often below 10 percent thereof, and consequently has, in this respect, only a slight influence on the concentration. on the other hand, the speed at which this air passes through a cartridge is important to the concentration since the air flow velocity through the cartridge has a considerable influence on the rate of volatilization which is of decisive influence on the concentration as the volume of odorous substance introduced into the ventilating air during a given space of time is equal to the volume of vapour which is contained in the air originating from the cartridge within an equally long immediately preceding space of time. The possibility of adjusting the rate of volatilization by varying the air flow velocity is, however, generally rather limited within the velocity range with which it is practical to operate in the separate air feed system.

In order that the air flowing out from the cartridge is going to contain a certain volume of odorous substance in the form of a vapour within a given space of time, it is imperative that within this space of time the adequate volume of vapour be available and that the desired volume be transferred to the air flowing out from the cartridge within the stipulated space of time.

The cartridge contains a porous filling as, for example, glass beads, on the surfaces of which the odorous substance or a solution of same, e.g., in alcohol, is adsorbed and thus is present in the form of a thin film of liquid. The air contained in the spaces between the glass beads will be saturated relatively quickly with vapour emanating from the odorous substance and the solvent to be possibly used; consequently it can be assumed that, as a rule, it is saturated at the time when the air from the separate ventilating system is sent through the cartridge, provided that the volume of liquid introduced is sufficient to bring about a saturation. Failing this, the entire volume of liquid introduced is obviously present in the form of vapour in the spaces between the glass beads.

When the air from the separate ventilating system is sent through the cartridge, the vapour present there will be carried along by the air and removed, by and large, at the same speed as the flow velocity of the air. Any remaining liquid will then at once begin to volatilize and in order to get the requisite volume of air transferred to the air within the space of time desired, a certain rate of volatilization is consequently necessary. This depends upon the odorous substance and of the possible solvent as well as of the surface of the liquid coming into contact with the air that passes by, as well as of the partial pressure of the vapour in the air.

Consequently it is possible for a regulation of the rate of volatilization to take place by a variation in the surface, for instance, by varying the size of the glass beads used or by replacing the glass beads with other adsorbents. The partial pressure of the vapour in the air flowing through is nil at the intake end and increases to a maximum value at the discharge end unless it is saturated before reaching that far, it will thus have to be taken into account when regulating that the rate of volatilization decreases from the intake end towards the discharge end. When employing a solvent, this partial pressure also is of importance to the rate of volatilization of the odorous substance, which circumstance can also be utilized when regulating since it is only the volume of vapour of the odorous substance itself that matters, while the vapour volume of the solvent, which is assumed to be neutral, can be large or small without having any influence on the effect of the odour.

The speed at which the air from the separate ventilating system is injected into the auditorium also is of importance to the concentration as this injection results in a certain turbulence whereby the odorous substance is mixed with the ventilating air introduced into the auditorium. The higher the velocity is with which the air is injected from the separate ventilating system, the greater the area is going to be over which the turbulence is present and the greater the volume of air is with which the volume of odorous substance carried along is mixed.

The sensing threshold value is defined as the weight of the odorous substance in question which is to be distributed in a certain volume of atmospheric air so that an average person, after having been in normal air for a suitable period of time, is just able to notice the odour when he moves into the air volume in which the odorous substance is distributed. The determination of the sensing threshold value of an odorous substance has to be carried out by means of an appropriate number of test persons according to the rules usually applied when examining sensing phenomena. The threshold value is suitably expressed in milligrammes per 100 m.sup.3 and for a number of usable odorous substances, values will be obtained thereby that lie in an interval of from 10.sup.4 to 10.sup..sup.-3, depending upon the composition and odorous nature of the substance.

It is important that, prior to each test, the test audience spends afair amount of time, e.g. 20 minutes, in a normal atmosphere, that is to say in an atmosphere devoid of any distinctive odours as it is otherwise possible for a so-called deafening of the sensing threshold to occur which may distort the results.

The sensing threshold value of different odorous substances may be found in literature dealing with such substances, however, these values can only be regarded as being of a guiding nature since these values are arrived at under test conditions which generally will have to be assumed to differ greatly from those conditions which are present when the present invention is applied in practice, so that it will have to be regarded as expedient that in each auditorium in which the invention is to be employed, tests are carried out under conditions which, as far as this is possible, correspond to those normally prevailing when using the invention, in order to establish the practical sensing threshold values established for in the instance in question.

The minimum size of the dose supplied, or the quantity with which the odour dose is to exceed the dose which corresponds to the theoretical magnitude of the threshold value, depends particularly on the movement of the air in the auditorium.

When the air renewal takes place by a completely laminar flow with the air being introduced at the ceiling and extracted at the floor, the air volume in which the odorous substance is introduced will move downwards into the auditorium at a velocity corresponding to the air renewal period while retaining the concentration during the whole movement through the auditorium as the odorous substance, to all intents and purposes, is not mixed with the masses of air it encounters which are supplied immediately prior to and after the supplying of odorous substance has taken place. This is owing to the fact that in case of a laminar flow the mixing takes place merely by diffusion and the velocity of diffusion is quite negligible in relation to the velocity of movement of the air down through the auditorium.

Such a laminar flow of air will, however, almost never take place in practice since some turbulence will always have to be allowed for, particularly in the injection area proper. This results in that each air volume which is introduced into the auditorium will, to a greater or lesser degree, be mixed with air supplied ahead of this volume of air, as well as with air that is supplied after this volume of air, which results in a corresponding dilution of the odorous substance and, thereby, in an increase in the quantity of odorous substance to be introduced per unit of time so that the concentration is to exceed the sensing threshold value at the moment when the air volume reaches down to the zone of the auditorium occupied by the audience.

The invention is based on the recognition that, in order to obtain a controlled distribution of odour, as little of the odorous substance as at all possible has to be introduced and the odorous substance has to be quickly removed again, and according to the invention, it can therefore, be advantageous to employ a dose of such a size that the concentration in the auditorium is brought down below the threshold value within a space of time which is less than one air renewal period.

If a sustained odour effect is desired in the auditorium, then it is possible to achieve this by periodically repeating the supply of the odorous substance so that the concentration alternately lies above and below the threshold value and in such a way that the intervals in which the concentration lies below the threshold value are longer than those intervals in which the supply of odorous substance is effected.

It is possible to thereby achieve an odour effect of any desired duration without any particular "deafening" with respect to the odour occuring, which would often be the case in a continuous supply of the odorous substance with the result that, in order for the odour to be continuously noticed, the concentration had to be constantly increased during the space of time desired which, among other things, would have the result that the effect of the odour on members of the audience who have been in the auditorium from the start and persons who only enter the auditorium later, is going to be widely different and, for the latter, often highly unpleasant. It could moreover result in an inexpedient effect in that case where, subsequent to the termination of the supply of odour in question, it is desired to supply another odour. There is, namely, a risk of the presence of a substantial volume of the first odourous substance affecting the odour impression resulting from the other odorous substance, and further the "deafening" effect of the first odorous substance supplied is often not entirely selective so that the sensing threshold value of the new odorous substance with respect to the members of the audience that are present may be higher than the normal one.

In addition it is consequently expedient that different odorous substances be successively supplied in such a way that the supply of another odorous substance is only begun with after the concentration of the previously supplied odorous substance has fallen below the threshold value valid for same when the other odorous substance is present.

The method according to the invention can be utilized in different fields, e.g., in business and restaurant premises where it can be used for creating different background odours to be certain extent on the lines of the background music so frequently employed. Further it can be used to produce an odour accompaniment for a film show by effecting the supply and selection of the odorous substances in conformity with markings on the strip of film used in the film show.

As mentioned above, the sensing threshold value of the different odorous substances lies within a very wide range. In all instances only small amounts are to be used, but particularly for the substances with the lowest threshold values it is a question of such small amounts that, to all intents and purposes, it would be impracticable to use them in their pure form.

The problems connected herewith are solved in a special embodiment of the method according to the invention in that the odorous substance, prior to being introduced into the air supply system, is dissolved in a volatile solvent, the sensing threshold value of which is higher than corresponding to the amount of solvent containing the dose of odorous substance used and which is indifferent with respect to the odorous substance.

When the stated requirements are met, the solvent will not have any influence on the effect of the odour. Various solvents exist fulfilling these conditions. In principle, water will be particularly suitable since the sensing threshold value of water has to be regarded as lying above the point of saturation, at any rate for human senses, however, the applicability of water is limited on account of a number of odorous substances being water-insoluble and because of water not being indifferent with respect to every odorous substance that is water-soluble.

Another solvent which has proven to be particularly suitable is ethyl alcohol as it has been established that pure alcohol has a very high threshold value and since, at the same time, it is considerably more volatile than water, a rapid and convenient distribution of the odorous substance is consequently achieved. By way of example, it is thus possible to achieve that, instead of a dose of 0.01 mg per 100 m.sup.3 corresponding to the sensing threshold value, the same amount of odorous substance may be used dissolved in 2 to 3 mg alcohol or more.

Furthermore, the invention relates to a device for use in performing the method according to the invention and this device is, according to the invention, characteristic in that it comprises an air injection system with an air duct that is adapted to accommodating a cartridge containing a measured dose of odorous substance and is connected to a large number of injection nozzles which are fitted distributed in the auditorium or premises in which the odour is to be introduced, in addition to which this auditorium or these premises are connected to a device for renewing the air in the auditorium or premises at a frequency of at least 20 times per hour. It is of prime importance that a large number of injection nozzles are used since it is possible thereby to rapidly achieve a distribution of the odour in the auditorium or premises.

The nozzles may terminate directly in the auditorium independently of the air supply system, they may, however, also be mounted in the distribution ducts forming part of this air renewal system in front of the injection apertures of the system leading into the auditorium, but also in this instance a large number of injection nozzles ought to be used so that the relatively small odour-laden volume of air can be uniformly distributed across the entire cross section of the large volume of air which flows through the air renewal ducts.

Finally, the invention relates to a cartridge for use in a device as the one described and the characteristic feature of this cartridge consists in that it comprises a prismatic or cylindrical cartridge case which is open at both ends, which cartridge case is, at its ends, provided with sealing means for sealing contact between two parallel surfaces and which contains a porous neutral carrier material having a large active surface and great power of adsorption with respect of solutions of the odorous substances employed, for example, glass beads, water-saturated silica gel, glass fibre, stainless steel wool, etc. In this manner it is possible to have exactly the desired dose of the odorous substances yielded given off and the odorous substances become easy to handle prior to their use whether the cartridges be filled in the feed mechanism of the device or whether the cartridges be supplied filled ready to the place of use, e.g., in cassettes fitting the supply aperture of the device.

In the following, the invention is explained in greater detail with reference to the accompanying drawings, in which

FIG. 1 schematically shows an embodiment of the device according to the invention,

FIG. 2 shows another embodiment of this device,

FIG. 3 shows a detail of the device illustrated in FIG. 1 or FIG. 2 in a modified embodiment,

FIGS. 4 and 5 show an embodiment of another detail of the device according to the invention,

FIG. 6 shows a cartridge for use in the device according to the invention,

FIGS. 7 and 8 show a modified embodiment of the detail illustrated in FIGS. 4 and 5, and

FIG. 9 shows a simplified flow sheet of a control circuit according to the invention.

In the embodiment of the device according to the invention as shown in FIG. 1, 1 denotes an auditorium or premises in which various odours should be introduced.

The auditorium is ventilated by means of a ventilating system which, in the figure, is merely indicated by a blower 2 and an air supply duct 3 that terminates in the auditorium 1 underneath the ceiling of same in a large number of apertures 4 which are evenly distributed over the area of the entire ceiling. The air discharge from the auditorium takes place between slots 5 at the foot of the wall of the auditorium, which slots 5 are connected with a discharge duct 6.

Since a recirculation of parts of the discharge air from duct 6 will also result in a recirculation of odorous substances in the discharge air, the use of a ventilating system with recirculation is generally out of question. However, it is possible to utilize a ventilation system of any type from the simplest consisting merely of a blower injecting fresh air into the auditorium to the most complicated air conditioning plant with air cleansing the automatic control of the temperature and degree of humidity of the air supplied since the only demand made of the system is that the auditorium be thereby ventilated at an air renewal frequency of at least 20 times per hour.

The device shown in FIG. 1 contains, moreover, a separate air supply system with an intake duct 7, a blower 8 and an injection duct 9 which ends in a plurality of injection apertures 10 fitted in the auditorium or premises 1 a short distance below the injection apertures 4 and, just like these, evenly distributed over the entire ceiling area of the auditorium.

Before the connection to the blower 8, the intake duct 7 branches into a plurality of parallel-connected ducts 11 and 12. In the ducts 11, of which there may be any desired number, odour cartridges are inserted during the operation of the device. The cartridges are receptacles containing an odorous substance in liquid form absorbed in or adsorbed on a suitable carrying material, e.g. glass wool, glass beads, steel wool, silica gel or other materials that are neutral indifferent with respect to the odorous substance and do not offer too strong an air flow resistance.

In duct 12, a similar cartridge having the same air flow resistance, but not containing any odorous substance is mounted. The odour cartridges in ducts 11 are designated by 13 while the dummy cartridge in duct 12 is designated by 14. Both the odour cartridges 13 and the dummy cartridge 14 can be designed in such a way that they can be inserted into and completely fill in interruptions in ducts 11 and duct 12.

In the embodiment shown, each of the odour cartridges 13 is provided with a stop valve 15 in each end so that an airtight closure can be achieved for so long as the cartridge is not inserted into the device as well as subsequent to its removal therefrom.

Moreover, in each of the branch ducts 11, stop valves 16 are fitted before and after the places where the cartridges are inserted.

The dummy cartridge 14 does not have to be constructed with stop valves and, likewise, only a single stop valve 17 is present in duct 12, into which the dummy cartridge is inserted.

The stop valves 16 are necessary even if the cartridges are provided with valves 15 for safeguarding the operating staff from too strong concentrations of escaping odorous substances when a cartridge is removed. For the same reason the cartridges, as shown, ought to be at the intake side of the blower 8 so that a certain sub-pressure is produced in the branch ducts 11.

For so long as no odour is to be introduced into the auditorium, the valves 16 and possibly valves 15 are closed while valve 17 is open so that air is only drawn in through the dummy cartridge 14 which does not supply any odour to the air. When an odour is to be introduced, valves 16 in the branch duct in which the cartridge 13 in question is located, are opened, just as valves 15 are also opened, while valve 17 is closed. The air is now drawn through cartridge 13 by suction and carries along odorous substance in the form of vapour and this odorous substance is introduced with the air via nozzles 10 into the auditorium, whereby the odour is mixed in the main air flow originating from nozzles 4. The odorous substance may be disposed in the cartridge in a dosed quantity so that the cartridge is completely emptied of odorous substance by injecting the desired dose; it may, however, also contain a larger amount of odorous substance and, if this is the case, the dosage has to be controlled by means of the valves so that valves 16 are closed and valve 17 is opened after a time corresponding to the injection of the desired dose. This control can also take place by controlling the fan 8, in that instead of letting same run continuously, it can be started and stopped in consonance with the supply of odorous substance.

Normally it will be expedient, however, for the blower 8 to operate continuously, partly because a sub-pressure is thereby produced in the branch ducts so that it is possible to remove the cartridges without any risk of the staff being exposed to too strongly concentrated, unpleasant odours, and partly, because variations in the total air volume flowing through the auditorium per unit of time are avoided thereby.

The use of the blower at the discharge side of the branch ducts does, however, give rise to noise problems whereas the noise problems can be greatly reduced if the blower is mounted on the intake side of the branch ducts. However, these will thereby be located on the high-pressure side involving the previously mentioned inconvenient effects for the operating staff.

It is, however, possible to employ a combination of the two possibilities so that a considerably weaker blower may be used on the discharge side of the branch ducts producing a correspondingly reduced noise, such an embodiment is shown in FIG. 2.

In the embodiment shown in FIG. 2, a blower 18 is mounted on the intake side of the branch ducts and a blower 19 on the discharge side of the branch ducts, however, the construction differs from the one shown in FIG. 1 in that only stop valves 17 are present in duct 12 but no dummy cartridge.

The blower 18 is dimensioned so as to provide the requisite air volume through the cartridges and it is controlled in conjunction with the valves in such a way that it is started when valves 16 are opened and stopped when they are closed.

The blower 19 is dimensioned so as to provide the same volume of air when the valve 17 is opened and valves 16 are closed and the blower 18 is thereby stopped. Consequently, this blower 19 can be dimensioned for a considerably lower pressure than the blower 18 since there is no substantial air flow resistance through duct 17 as compared to the air flow resistance through a cartridge and it is possible, therefore, to construct it with a considerably lower noise level. The blower 18 is separated from injection duct 9 by means of the cartridges that have a substantial sound-attenuating effect so that the device becomes considerably more noiseless than the one shown in FIG. 1. A noise trap may possibly be fitted on the discharge side of blower 18 as indicated with 20.

When blower 18 is stopped, blower 19 produces the requisite sub-pressure in the branch ducts for allowing the removal of the cartridges without any inconvenience.

FIG. 3 shows a detail of the device illustrated in FIG. 2 in a modified construction. In this construction , duct 9 is lead into duct 3 and its terminations 10 are immediately in front of the terminations 4 of duct 3, so that in this case the mixing of the odour-saturated air and the main air flow takes place prior to the injection into the auditorium.

FIGS. 4 and 5 show a cartridge feeding device for use, for example, in the device according to FIG. 2, where they take the place of the unit formed by branch ducts 11 and 12. This device comprises a drum-like container 25 with plane side walls 26. Centrally and closely-fitting in this container, a shaft 27 is mounted, which is supported in bearings 28 and bears a driver 29 for a plurality of odour cartridges 30.

The container comprises a jacket 31, in which there is an opening 32 that is connected to a stud 33 with two plane parallel side walls 34 which are mounted in such a way that their insides form a direct continuation of the insides of the side walls 26 in the drum 25. The cartridges 30 are cylindrical and open at the ends where sealing means 35 are fitted that form a sealing contact between the side walls 26 and the cartridge in question inserted between them.

In each of the two side walls 26, there is an opening 36 which is of a size that is, at the most, equal to the internal cross section of the cartridge and, surrounding these openings, on each of the sidewalls 26 an outwardly extending stud 37 is secured.

When used in a device as the one shown in FIG. 2, the discharge duct of the blower 18 is connected to one of these studs 37 and the intake duct of blower 19 is connected to the other one of these studs 37.

The cartridges are filled with glass beads or some other porous material having a suitable pore and surface size and which are indifferent with respect to the odorous substances used.

An empty cartridge can be introduced between stud 33, so that its seals 35 fit tightly against the inside of wall 34, thus sealing the cartridge completely. In one of these side walls 34, a connection piece or stud 38 is fitted with a self-closing valve, not shown.

When a cartridge, during insertion, is located inside stud 34, it will be possible to carry out the filling of the cartridge with an odorous substance with the aid of a syringe through stud 38.

From there, the cartridge can be inserted further into the drum for engagement with the driver 29. By rotating the shaft 27, the cartridge is, by means of a driver 29, moved in a circular path inside the drum into a position where it lies in front of the openings 36 where it thus is possible to effect a blowing through with the aid of blower 18 for introducing the odorous substance into the ventilating air.

In every other position of the cartridge inside the drum there is a sealing contact against side walls 26 so that the cartridge is completely sealed off from the surroundings except just in the position in front of the openings 36, and in this way it is possible to have, at one time, a certain number of cartridges in readiness inside the drum ready for being moved ino the active position at will.

The emptied cartridges may be removed one by one through stud 34. In the example shown in the drawings, the removal mechanism is shown in a very simplified manner, that is to say as a rod 40 with a thread that is screwed into a nut 41, matching the thread of the rod.

In the embodiment shown there is room for four cartridges inside the drum, however, there is nothing to prevent the drum and carrier from being constructed in such a way that a larger number of cartridges can be used simultaneously.

Moreover, a special outlet duct can be constructed similar to duct 33. In principle it is possible for the same construction to be used also for cartridges that are filled in advance, however, in such a case the cartridges will have to be provided with stop valves at their ends so that they are sealed even before being inserted into the device.

It is also possible to employ linear feeding instead of the rotating feeding shown in the drawings, for instance, by means of a conveyor belt with carriers.

FIG. 6 shows a special embodiment of an odour cartridge. This comprises a cylindrical cartridge case 50 with terminal faces 51 which eacb have a central aperture 52 sealed with a valve plate 53 which is connected with a spindle 54 that is axially displaceable inside the cartridge and which forms the movable core of a magnet coil 55 which is common to the two valve spindles 54. The valves are each loaded by a spring 56. When an electric current is sent through the magnet coil 55, the two valve spindles are drawn towards each other into the coil whereby they open the valves against the action of springs 56. The cartridge contains a carrying material 57, e.g., glass beads or glass wool, silica gel, for example, in a water-saturated state, stainless steel wool or other porous material which is indifferent with respect to the odorous substances employed, as well as with respect to the dissolving agents possibly used for them, and which posses the requisite porosity for not offering too great an air flow resistance, while at the same time the surface is of a sufficient size so that the doses of odorous substances employed can be adsorbed on the surface in the form of a thin film.

FIGS. 7 and 8 illustrate a number of such cartridges 68 and 69 mounted on a suction box 70 above a corresponding number of apertures 71 in the plane top 72 side of the suction box as is indicated in FIG. 6.

The construction shown in FIGS. 7 and 8 can be used in connection with a device similar to the one shown in FIG. 1, in which the suction box with the fitted cartridges, if that is the case, replace the branch tubes 11 and 12 with the cartridges inserted therein. On account of the partial vacuum produced in the suction box 70 and the air flow resistance present in the cartridges, these can be secured fitting tightly against an elastic seal 73 which likewise is indicated in FIG. 6. In this manner it is easy to remove the cartridges since the securing force, due to the partial vacuum in the suction box 70, generally is not greater than that it can be overcome without any difficulty by manually removing the cartridge.

Filling the cartridges with odorous substance may, for example, be effected, as indicated in FIG. 6, through a self-closing valve 74 in the one terminal face 51. The detailed construction of this valve is irrelevant to the invention and has consequently not been shown in greater detail.

The five cartridges 68 shown in FIGS. 7 and 8 are odour cartridges while cartridge 69 is a dummy cartridge which is designed in quite the same way without, however, being filled with any odorous substance. The cartridges have a connecting plug 75 as indicated in FIG. 8, by means of which their magnet coils are connected to a terminal strip 76. In connection herewith a keyboard 77 with five keys 78 each corresponding to its cartridge is fitted, while no key has been provided for cartridge 69. A simplified electrical circuit for controlling the valves of the cartridges is shown in FIG. 9 which shows a current source 79, one pole of which is connected to one end of each coil 55 and to one end of a coil 81 associated with the dummy cartridge 69. The other pole of source 79 is connected to the other end of coil 81 through a plurality of series connected change-over switches 80 each corresponding to one cartridge 68. As shown, the switches 80 are connected in series in their normal or rest position, and each coil 55 is connected to the switch contact of one of the switches 80.

Thus, in the position of rest, current passes through coil 81 but not through coils 55, which means that the valves in the dummy cartridge are open while the valves in the odour cartridges 68 are closed.

The change-over switches 80 are operated by means of keys 78 and by pressing down one of these keys 78, the current will be switched on through the associated magnet coil 55 while the remaining magnet coils remain without current and the current passing through coil 81 is interrupted.

The connection between the keys 78 and the change-over switches 84 may be purely mechanical, but it is also possible for an electrical control to be connected between them and the change-over switches 80 may be electronic ones. Such electronic change-over switches can, moreover, be operated by means of suitable markings on a strip of film instead of by the means of keys in the case where it is desired to have an odour supply that is controlled by the advance of the film strip for accompanying the showing of a film.

In FIG. 7, an intake air box 82 is indicated with dot-and-dash lines which is constructed analogously to the suction box 70, so that the cartridges 68 and 69 are fixed between these two boxes. Thereby it is possible in a simple manner to also utilize the arrangement in connection with a device like the one shown in FIG. 2.

EXAMPLE

A number of tests were carried out in a test auditorium having a length of approx. 7 metres, a width of 4 metres and a height of 3 metres, totalling apporx. 85 m.sup.3. The auditorium is adapted to the showing of films with accommodation for 20 persons.

The ventilation system is designed in conformity with that shown in FIG. 2 and with the possibility for a change of air varying from 0 to 50 times per hour, that is to say a yield that can be adjusted from 0 to 4,250 m.sup.3 per hour. The injection of the fresh air takes place through a perforated ceiling with holes having a diameter of 7 mm with approximately 175 holes per m.sup.2.

The special air supply system serving to introduce the odour is constructed, as in FIG. 2, with two fans providing an air volume of about 300 m.sup.3 per hour. The first of these fans, which corresponds to the fan 8 in FIG. 2, provides with this air volume a pressure of about 550 mmVS. This fan is started only when opening for air to pass through an odour cartridge.

The other fan, which corresponds to fan 19 in FIG. 2, continues to operate and with the air volume stated provides a pressure of 40 mmVS, which is sufficient to maintain a sub-pressure in the branch ducts so that it is possible to remove the cartridges without causing any inconvenience to the operating staff. At the same time, this fan brings about a scavenging of the entire device of possible residual odours. From this separate injection system the air is conducted to the auditorium via a duct system which leads to 16 injecting points mounted in two rows of eight each underneath the injection apertures of the first-mentioned ventilating system and so that each injecting point is positioned in the centre of one-sixteenth of the area of the auditorium.

The cartridges utilized had the shape of cylindrical cartridge cases with a diameter of 100 mm and a length of 80 mm and were tightly packed with glass beads whose diameter was approximately 5 mm.

A test was carried out involving four different odorous substances, viz. benzaldehyde which yields an odour of almonds, amylacetate, which yields an odour of bananas, butyric acid which yields an odour of perspiration and ethylmercaptan which yields an odour of rotten cabbage.

Pure ethyl alcohol was used as a solvent and a 20 percent solution was used of the first two substances, a 2 percent solution of the third and a 1 percent solution of the forth substance.

Suitable quantities were weighed out judged from the known theoretical threshold values of the substances in question, which are 430, 3,900, 900 and 6,400 mg, respectively, per 100,000 1, as it was assumed that the turbulence in the auditorium would be of such a magnitude that the volume of air injected would be distributed in the total cubic content of the auditorium in the time it takes for a given air volume to move from the ceiling to the zone of the auditorium occupied by the audience in that at the same time regard was paid to experience gained from many preceding tests relating to the rate of volatilization.

It was proven that in order to obtain the odour characteristic for the individual substances and, at the same time, to be able to remove all trace of odour within a space of time of 1 minute or less. 400 mg of the first two substances may be used, 40 mg of the third and 20 mg of the last substance.

It is remarked here, inter alia, that equally large amounts of the first two substances are used in spite of the fact that the theoretical threshold value of the second substance is about 10 times as big as that of the first one. As far as the first substance is concerned, a quantity is used which, by and large, corresponds to the threshold value, as regards the second substance, a quantity corresponding to one tenth of the threshold value, as to the third substance, a quantity corresponding to about one twentieth of the threshold value and, finally, as far as the last substance is concerned, a quantity which corresponds to only 1/225 of the threshold value.

This is connected with the different rates of volatilization of the different substances. As regards the last substance, the rate of volatilization is so high that it may be assumed that the entire quantity is converted into a vapour already during the insertion of the cartridge into the device so that the air flowing through needs only to be mixed with the volume of vapour present and to carry it along, which happens in less than 1 second under the present test conditions. As far as the other substances are concerned, it is assumed that the mass of air in the cartridge is saturated with the vapour of the odorous substance so that a certain amount is still left behind in the liquid state so that a greater or smaller part of the total amount begins to volatilize only once the air flow through the cartridge is started. With respect to the first substance, it is assumed that the largest part of the substance is in the liquid state.

Claims

1. An apparatus for the controlled introduction of odors into an auditorium comprising:

a. an air injection system having an air duct for receiving a cartridge containing a measured dose of the odorous substance, the received cartridge constituting a part of the duct,

b. a number of injection nozzles for introducing the odor,

c. means connecting the duct to the nozzles,

d. an air ventilization system for effecting an air renewal in the auditorium at least 20 times per hour,

e. a by-pass duct connected with the part of the duct which receives the cartridge, said by-pass duct being constructed to offer an air flow resistance of substantially the same magnitude as the air flow resistance in a cartridge,

f. valve means in the ducts for enabling a selective air flow through the cartridge or through the by-pass duct,

g. a plurality of duct sections connected in parallel with the by-pass duct and each being adapted to receive a cartridge,

h. valve means for enabling a selective air flow through the by-pass duct or any desired duct sections, and

i. a branch in the air duct comprising a distribution box and a collection box, a wall in the distribution box fitted parallel to a wall in the collection box at a distance corresponding to the length of a cartridge,

2. An apparatus for controlled introduction of odors into an auditorium comprising:

a. an air injection system having an air duct for receiving a cartridge containing a measured dose of the odorous substance, the received cartridge constituting a part of the duct,

b. a number of injection nozzles for introducing the odor,

c. means connecting the duct to the nozzles,

d. an air ventilization system for effecting an air renewal in the auditorium at least 20 times per hour.

e. a by-pass duct connected with the part of the duct which receives the cartridge, said by-pass duct being constructed to offer an air flow resistance of substantially the same magnitude as the air flow resistance in a cartridge,

f. valve means in the ducts for enabling a selective air flow through the cartridge or through the by-pass duct,

g. a plurality of duct sections connected in parallel with the by-pass duct and each being adapted to receive a cartridge,

h. valve means for enabling a selective air flow through the by-pass duct or any desired duct sections, and

i. a branch means in the air duct comprising a suction box having a plane external wall surface mounted at the intake end of the air duct, the suction box having a plurality of holes each adapted to receive the terminal face of an associated cartridge and sealing means for sealing the cartridge and suction box, whereby a number of cartridges can be mounted on the suction box with the sealing means secured to it by means of the

3. An apparatus for the controlled introduction of odors into an auditorium comprising:

a. an air injection system having an air duct for receiving a cartridge containing a measured dose of the odorous substance, the received cartridge constituting a part of the duct,

b. a number of injection nozzles for introducing the odor,

c. means connecting the duct to the nozzles,

d. an air ventilization system for effecting an air renewal in the auditorium at least 20 times per hour, and

e. further including a chamber with side wall plates, the air duct serving to accommodate the cartridge comprising an intake and a discharge line which are positioned opposite each other, and are each connected to one of two mutually connected plates having plane parallel lateral surfaces that are facing each other, the plates form side walls in the chamber which are sealed apart from the connection to the intake and discharge lines, and wherein a drive is fitted within this chamber for moving a plurality of cartridges such that a single one of these at a time can be brought into a position in which it forms a connection between the intake and discharge line while the others occupy positions in which they are sealingly fitted to the side walls of the chamber and are sealed at both ends, and a wall of the chamber having a closable aperture connecting the side walls for

4. An apparatus as claimed in claim 3 wherein the driver is mounted inside the chamber and is rotatable around an axis perpendicular to the parallel

5. An apparatus as claimed in claim 3 wherein the closable aperture is connected to a stud with two side walls which form the continuation of the side walls of the chamber, and further comprising a filling stud in one of the side walls of the stud for inserting an odorous substance into a

6. An apparatus as claimed in claim 3 where the chamber has an additional

7. An apparatus as claimed in claim 6 wherein one of the apertures is connected with means for the continuous supply of cartridges and the other is connected with means for the continuous removal of cartridges.