US1882365A - Heating cartridge - Google Patents

Description

Oct. 11,- 1932. 5.1.." LUBELSKY HEATING CARTRIDGE Filed May- 16, 1929 Ben LLUbeISkg u r/I 'l ?atented BEN L. LUBEL, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO SAFETY MTNTNG COANY, 01E CHICAGO, ILLINOIS, A OOBL'OBATION TING *GARTBIDGE Application filed Hay 1a, 1929. Serial no. 868,545.

The present invention is concerned with the production of heat in predetermined quantities and within relatively short predetermined time intervals and the same is applicable to any use involving these conditions.

One very advantageous use of the heating means of the present invention is in connecshown in the copending application of Dent Ferrell and Arthur W. Helmholtz, Serial No. 169,441, filed February 19, 1927 and for purposes of illustration the present invention is herein shown as applied to a cartridge of this general type.

In blasting cartrid es of the type referred to the blasting me ium is a liquefied as such, for example, as carbon dioxide an it is essential that this medium be raised to its critical temperature ractically instantaneously in order to pro uce a substantially in-- stantaneous pressure "increase such as will operate the venting means of the cartridge and suddenl liberate the entire gaseous char e. A s ow increase of pressure due to the s ow development of heat within the cartlldie will result in an incomplete operation 0 t tive discharge of the cartridge.

Accordingly it is an object of this invention to provide a. means which is capable of producing a substantially predetermined amount of heat in a practically instantaneous manner.

It is also an object of the present invention .to provide a heat producing compound which is not sufiici'ently sensitive to friction and shocks to render the manufacture or handling of the same unsafe.

A further object of the invention is to provide a com ound of the character described which is re atively stable, that is, one which tridge containing a charge of liquefied gas under pressure and operative to efiect a substantially instantaneous vaporization of the charge.

e venting means and hence an inefiec-- Other more specific objects will ap ear in connection with the following detai ed description.

In the drawing,

Figure 1 is a view in longitudinal section of a blasting cartridge of the type hereinabove referred to and showing the improved tion applied thereto.

Figure 2 is an enlarged detailed view of the heat producing unit.

Referring to the drawing, it will be noted that the present invention is disclosed as embodied in a cartridge comprisin a casing having a rupturable disc 11 and a directing cap 12 at the discharge end and means 13 for establishing an electrical connection for the heating element and for introducin the blasting medium into the interior 14 o the cartridge. The cartridge construction will not herein be described in detail inasmuch as it is substantially the same as that shown in the copending a plication above referred to.

The heat pro ucing unit 15 is ada ted to be inserted in the position shown in igure 1 with its electrical connection 16 at one end thereof in contact with the rupturable disc 11 and the electrical connection 17 at the opposite end thereof in contact with the plate 18 constituting the other terminal for the electrical circuit.

Referring particularly to Figure 2, it will bc'observed that the heat producing unit structurally consists of a substantiall tubular container 19 within which the heating compound or mixture 20 isplaced. The oposite ends of this tube are referably closed y means of lugs 20' which. may be formed of wood, cor or any other suitable material. The container 19 is preferably formed of waxed paper or some other combustible material. The contacts 16 and 17 are formed on the respective ends of an electrical conductor 21 which passes entirely through the heating device from end to end. Any suitable arrangement may be made for accommodating the conductor at the opposite ends of the heating unit and as herein shown, the conducting wire simply passes between the casing 19 and the closing plugs 20'. The

- heat producing device of the present invention with blasting cartridges of the type and especially for use in connection with,

of the chlorate, perchlorate or nitrate groups, I

while the latter may be any suitable metal such, for example, as aluminum, carbon, magnesium or manganese or any suitable combination of these.

It has been found from extensive experiments that the perchlorates are far more suitable for the production of heat in general blasting cartridges of the type referred to. The reason for this is that the perchlorates have a greater oxygen content than do either I the chlorates or nitrates, thus making it possible to secure a given amount of heat with a less amount of the mixture. It has also been found that perchlorates are substantially more stable than the chlorates and for this reason their use under a variety of weather conditions is of considerable advantage. From the safety standpoint rchlorates offer advanta es over either t e chlorates or the nitrates us to the fact that the erchlorates are much less sensitive to ignition by friction or shock.

As hereinabove pointed out, there are quite a number of metals suitable for use as reducing agents. However, it has been found that aluminum is the most satisfactory for use in this combination. The only difliculty inthe use of aluminum is due to the fact that its temperature of ignition isrelatively high, thus requiring a considerable amount of heat to energize the mixture. This difli- ,c'ulty is overcome according to the present invention by addingto the mixture a relatively small quantity of a different reducing agent which has a relatively low ignition temperature. The most suitable secondary reducing agent thus far discovered is carbon, although it should be appreciatedthat any other reducing agent having a low temperature of ignition as compared with that of aluminum may be used to serve the same purpose. 18y combininfigtwo different agents of the character speci d it is necessar to use only suflicient heat to raise the secon ary reducing agent to the oint of i nitionand this a ent then 'ves o the ad itional amount 0 heat required to raise the primary reducing agent to its point of ignition.

The mixture which is generally described above may consist either of sodium perchlorate or potassium perchlorate together with aluminum and carbon or their equivalents.

It will be appreciated that the proportions in which these ingredients are used may-be varied in accordance with the work to be done. The following are examples of mixtures which have been found to be particularly suitable for use in connection with charged blasting cartridges. It will be n that one of these mixtures embodies sodium perchlorate whereas the other is based upon potassium perchlorate.

79.8% sodium perchlorate 14.65% aluminum 5.7% carbon It should be appreciatedthat the heat producing compound of the present invention may be put up in any desired form according to the requirements of different kinds 0 work. For use in connection with blasting cartridges it has been found desirable to enclose the heat producing mixture in a cartridgc-like tube as shown in the drawing The tube ma either be filled completely wi the heat pr ucing mixture orit may be filled in part by some inert substance such as fullers earth in case a less amount of heat is re.-

quired. In the present instance, where the compound is encased in a paper cartridge, it is desirable to re ard the paper or other material of which t e casing is made as a part of the reducing agent of the compound and to calculate the proportions of oxygen carrier and reducing agent so as to provide for the complete combustion of the container. The action of the improved heat roducing device should be apparent from t e foregoing description but may be briefly characterized as follows:

When it is desired to energize the heating device it is merel source of current t ereto so that the squib or matchhead 22 will be ignited. The heat produced by the squib or matchhead serves to raise the temperature of the reducing agents to the point of ignition and at the same time causes the oxygen carrier to give ofi free oxygen which then combines with the reducnecessary to connect a Ill ing agents to produce combustion. Once this combustion has been started it continues until the entire heating unit is consumed and in this way the amount of heat for which the particular heater has been designed is generated in a practically instantaneous manner.

By varying the amount of mixture used, the" amount of heat roduced ean be controlled within very fine imits.

It will be obvious to those skilled in the art that modifications can be made in the do tails and in the use of chemical equivalents, as well as in the matter of the structural form of the invention. Therefore, the invention is aaaaaas not to be regarded as limited in any way other than by the state of the prior art andas the appended claims may require.

I claim:

1. A heater for carbon dioxide blasting cartridges comprising a tubular aper container, closures for the ends of sai container, an electric igniting device within said container and having leads extending to the exterior thereof, and a chemical mixture within said container to be ignited by said i niting device and rapidly produce high eat, said mixture comprising potassium perchlorate, aproximately aluminum approximatel 14% and carbon approximately 6%.

2. X heater substantially as set forth in claim 1, characterized in that the quantity of potassium perchlorate is calculated to provide an excess of oxygen.

Signed at Chicago, this 14th day of May,

BEN L. LUBELSKY.

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