* GB785809 (A)

Description: GB785809 (A) ? 1957-11-06

Improvements in or relating to temperature-responsive means

Description of GB785809 (A)

PATENT SPECIFICATION 785,809 l 3 Ct Date of application and filing Complete Specification Dec 14, 1955. No 35959/55. \\\;/ ' Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 38 ( 5), B 1 S( 3: 4: 12), B 2 C 6 C 2. International Classification:-HO 2 c. COMPLETE SPECIFICATION Improvements, in or relating to Temperature-Responsive means We, FREDRIC LAFARGUE BEST, a British Subject, and BEST PRODUCTS LIMITED, a British Company, both of Felix Works, Felixstowe, Suffolk, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to temperature-responsive means, for an electrically heated kettle or like vessel for heating liquids, to effect a control action when a selected temperature has been attained Apparatus is known wherein rotation of a shaft is prevented by soldering the shaft to a surrounding fixed member; the shaft is able to rotate when the solder softens or melts on a rise of temperature and rotation of the shaft releases a spring-loaded member to open a control-switch for the heating circuit. According to this invention a temperatureresponsive means comprises a shaft having on it an axially directed cup of which the interior is of distinctly non-circular transverse cross-section, a fixed member of distinctly non-circular cross-section projecting into the cup and a fusible alloy contained in the said cup thereby preventing, when solid, rotation of the said shaft Since the said fixed member and the interior of the cup are of noncircular cross-section it is not necessary for the fusible alloy to be bonded to either the said fixed

member or the cup, thereby eliminating the necessity of fluxing and tinning the surface of the fixed member and the inside surface of the cup The shaft is therefore keyed to the said fixed member by the shape of the fusible alloy when it is solid. The said fixed member may be of rectangular cross-section and it is preferred to make the cross-section of the fixed member longer than it is broad, i e in the form of a blade. The internal section of the said cup may be rectangular and is preferably square. lPrice 3 s 6 d l According to another feature of this invention the said shaft is rotatable within a hollow tube in which the said fixed member is secured 50 Preferably the said fixed member is secured in heat-conducting engagement with the heating element of the kettle or the like. The temperature-responsive means according to this invention may conveniently 55 be used in conjunction with the controlswitch operating and resetting means described in our Application No 2,637/53, Serial No 767,501, instead of the temperature-responsive means described therein 60 In the accompanying drawings which illustrate one embodiment of this invention, Figure 1 is a sectional view of a temperature-responsive device according to this invention secured to an electric immersion 65 heating-element, Figure 2 is a sectional view of the device shown in Figure 1 on the line a-a, Figure 3 shows the device, illustrated in Figures 1 and 2, in conjunction with the 70 operating means described in our Application No 2,637/53 (Serial No 767,501) and Figure 4 is a view looking on the underside of Figure 3. Referring first to Figures 1 and 2, the 75 electric immersion heater element 10, illustrated as of horseshoe form, is mounted in a heater-head 11 whereby it is secured in the base of a vessel whereof the contents are to be heated A tube or casing 12 closed at 80 one end by a fixed member 13 is mounted between the limbs of the element 10 with its closed end in good thermal contact with the metal sheath of the heater-element 10 The other end of this casing 12 is open to the 85 outside of the heater-head 11 A shaft 14 is mounted in the casing 12, and the inner end of this shaft is provided with a cup 16; the horizontal cross-section of the interior of the cup is distinctly non-circular and may be for 90 example an oval, or a polygon such as a square This cup 16 is filled with the fusible alloy and the fixed member is formed with a part 17 projecting downwardly in the cup 16 so that the part 17 is submerged in the fusible alloy The horizontal cross-section of the part 17 is distinctly non-circular and is made, most conveniently, in the form of a blade, i e the horizontal cross-section is longer than it is broad and the interior of the cup

is made with a square horizontal crosssection Therefore the fusible alloy, when solid, forms a key whereby the cup 16 and the part 17 are locked to one another due to the interlocking shapes of the cup and the alloy and of the alloy and the blade This eliminates the necessity of cleaning and fluxing, and then tinning, the surfaces of the cup 16 and the part 17 which are in engagement with the fusible alloy. The shaft 14 is provided with a tongue and groove connection to an extension piece or spindle 19 (see Figure 3) and a screw 20 is a tight fit in the end of the spindle 19 and this screw is engaged in a bracket 21 to constitute a bearing for the spindle 19 and shaft 14 The bracket 21 is secured on a base 22 of a suitable dielectric material, this base being mounted on the heater-head 11. An operating arm 23 is loosely mounted on the shank of the screw 20 and it is coupled to the spindle 19 by a helical spring 24 which is tightly coiled around the spindle 19, one end of the spring abutting a shoulder 25 on the spindle 19, the other end of the spring 24 is formed as a radially extending arm 26 which is engaged with the arm 23 in any suitable manner, as for example by pressing a tubular boss 27 out from the arm 23. An operating spring for the arm 23 is constituted by a few helical turns 29 loosely engaged with the screw 20, and one end of this spring is anchored at 30 in an opening in the bracket 21; the other end of this spring 28 extends radially and is engaged with the arm 23 by hooking it over an edge thereof This spring is arranged so that it tends to swing the arm 23 about the axis of the spindle 19 in the direction in which such movement causes the helical spring 24 to bind on the spindle 19 and constitute a one-way clutch between these parts Movement of the arm 23 in the opposite direction about the axis of the spindle 19 can take place freely, because the coils of the helical spring 24 are opened by this movement and do not bind on the spindle. This application of the invention to the heating-element 10 is arranged to cut off the current supply to the element when it, or that part of it near the closed end of the casing 12 and the fixed member 13, has attained the pre-determined temperature This temperature is determined by the selection of an appropriate fusible alloy. For this purpose a switch is connected in series with the heating element and it is constituted by two contacts 31, 32, see Figure 4, whereof in this construction the contact 31 is carried on a rigid rod or bar 33 and the contact 32 is carried on a resilient arm 34. The operating arm 23 carries an abutment 70 36 which conveniently is in the form of a disc of insulating material which is so positioned that it engages the end 35 of the spring arm 34 when the arm 23 is in its operative position towards which it is moved by the 75 spring 28, 29, 30 It is shown in this position in Figure 4, and the contacts 31,

32 have been separated by this movement of the arm 23 When the arm 23 is swung clockwise in Figure 4, the spring arm 34 brings the con 80 tact 32 into engagement with the contact 31. This device operates as follows T-he arm 23 is normally in its inoperative position and the circuit for the heater is closed by the switch 31, 32 The fusible alloy is solid and 85 holds the shaft 14 and spindle 19 against rotation, and the clutch spring 24 locks the arm 23 to the spindle 19 so that it cannot move When the heater-element 10 attains the pre-determined temperature, the fusible 90 alloy softens or melts, and the shaft 14 is thereby free to rotate This rotation is imparted to it by the spring 28 operating on the arm 23, and through the clutch spring 24 to the spindle 19, and the movement of the 95 arm 23 to the position shown in Figure 4, which is its operative position, separates the contacts 31, 32 so as to open the circuit to the heater The current supply has therefore been cut off on the attainment of a pre 100 determined temperature. When the heater element 10 cools down, the fusible alloy hardens or sets and thereby locks the shaft 14 against rotation; when another heating period is required, the arm 23 105 is swung back to its inoperative position and this can be efected since the clutch spring 24 disengages the arm 23 from the spindle 19 When, however, the arm 23 is in its inoperative position, the spring 28, 29, 30 is 110 stressed, and tends to return the arm to its operative position but it cannot do so, since the clutch locks the arm to the spindle 19 which cannot rotate after the fusible alloy has set 115 The coiled portion 29 of the spring is arranged to be in axial compression so that it presses the spindle 19 and thereby the shaft 14 inwards in the casing 12, so that cup 16 surrounds the blade 17 and engagement with 120 the fixed member 13 effectively seals the space containing the fusible alloy. Stops 37 and 38 are preferably provided to define the positions of the operating arm 23 when inoperative and operative respectively 125 The temperature-responsive control as applied to an immersion-heater element in the manner above described, is particularly suitable for use as a safety switch to prevent damage to the heating element in the event 130 785,809 the internal section of the said cup is square. 6 A device according to any one of the 25 preceding claims wherein the said shaft is rotatable within a hollow tube in which the said fixed member is secured. 7 A device according to any one of the preceding claims wherein the said fixed 30 member is secured in heat conducting engagement with the heating-element of a kettle or the like. 8 A temperature responsive device substantially as described with reference to and 35 as illustrated in Figures 1 and 2. 9 A temperature-responsive switch substantially as described with

reference to and as illustrated in Figures 3 and 4. A kettle or the like provided with a 40 temperature responsive device substantially as described with reference to and as illustrated in Figures 1, 2, 3 and 4. BOULT, WADE & TENNANT, 111 & 112, Hatton Garden, London, E C 1, Chartered Patent Agents. of it being switched on when the element is not fully immersed, or of the liquid boiling away.

* Sitemap * Accessibility * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785810 (A)

Description: GB785810 (A) ? 1957-11-06

Improvements in or relating to convertor bottoms

Description of GB785810 (A)

PATENT SPECIFICATION 785,810 Date of Application and Filing Complete Specification: - January 25, 1956. No 2480/56. Application made in Luxembourg on February 5, 1955. Complete Specification Published: November 6, 1957. Index at acceptance:-Class 72, C 1 A. International Classification: C 21 c. COMPLETE SPECIFICATION Improvements in or relating to Convertor Bottoms. We, A R B E D Acieries Reunies de Burbach-Eich-Dudelange, Societe Anonyme, a Company organised under the laws of the Grand Duchy of Luxembourg, of Avenue de la Liberte, Luxembourg, The Grand Duchy of Luxembourg, do hereby declare the invention, for which we pray that a

patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to convertor bottoms provided with tuyeres or blow holes and is concerned with facilitating the adaption of such convertor bottoms to varying operating conditions and also with prolonging the effective operational life thereof. A convertor bottom in either a basic or acid convertor is generally perforated with holes known as tuyeres or blowholes, so that refining gases may be passed through the perforations The total area utilized by these tuyeres in the bottom, which is known as the tuyere area, is of course dependent on the weight and composition, both chemical and physical, of the metal to be treated as well as the refining gas employed Thus, for example, when the convertor is operating and blowing with ordinary air, the tuyere area is between 8 and 25 cm 2 per ton of steel; the use of air enriched to 30 % oxygen, for example, enables the tuyere area to be reduced slightly, whilst the use of mixtures still richer in oxygen, or 02-C 02 or 02-H 20 mixtures, necessitates a greater reduction in the tuyere area, which is then reduced by to 70 % The use of methods employing surface blowing with oxygen requires that the tuyeres be completely dispensed with, whilst if combined surface blowing and bottom-blowing refining processes are used, it will be necessary to retain a number of tuyeres in the bottom. Thus the tuyere area of convertor bottoms is in practice anything between 0 and 25 cm 2 per ton of steel. It will be seen that a steelworks, which has to deal with pig irons of variable quality or has to use simultaneously several of the processes indicated hereinbefore, for reasons 50 of quality and / or costs, must either have available a large number of different bottoms or else must be able to stop up a number of tuyeres The tuyeres are usually blocked by introducing and ramming refrac 55 tory materials, which may or may not be mixed with organic binders, into the upper parts of the tuyeres in contact with the metallic bath or throughout the entire length of the tuyeres In the large majority of 60 cases, cavities continue to form in the tuyeres thus stopped, and this necessitates frequent repair work; moreover the heat of the metallic bath and of the convertor bottom results in the refractory material being 65 baked or sintered so that it becomes practically impossible to re-open tuyeres which have thus been blocked. Therefore charges which are to be worked according to a given process must be blown 70 consecutively in one and the same convertor which deprives the steelworks of any flexibility in working and causes difficulties in the organisation of the works, so that it is generally

preferred to use convertor bottoms 75 having an average tuyere area; this average cross-section is too small for some of the processes envisaged, and too large for other processes, and results in practice in an increase in the duration of blowing when the 80 former processes are being employed, and in an excessive diminution of the duration of blowing when the latter processes are being employed The quality of the steels produced is thereby lowered and excessive 85 wear takes place on the bottoms. According to one aspect of the invention there is provided a method of adapting a convertor bottom provided with tuyeres to varying operating conditions wherein any or 90 each of said tuyeres is hermetically plugged at the -lower tuyere orifice in a manner which permits ready withdrawal of the plug for re-opening the tuyere. According to another aspect of the invention, a convertor bottom is provided with tuyeres in excess of the maximum number required for refining operations, surplus tuyeres being plugged according to the method indicated and the tuyeres being employed selectively until the bottom is completely worn out. The lower orifice of any one of the tuyeres, which usually have their lower orifices situated in a cast iron or steel plate forming a base for the convertor bottom, may be hermetically stopped by means of a sealing plug made of metal, refractory material or plastic or like material, which is screwed or crimped either into the base plate or into the metal tube which is often used to line the tuyere An effective seal between plug and tube or between plug and plate can be guaranteed by using known intermediate packings such as lead, asbestos, or plastic materials. Another way of carrying out the invention is to introduce into the lower orifice or into the tube, a plastic plug of self-hardening or heat hardening material, and to make this plug hermetically tight by applying a lacquer thereto or by placing a metallic covering thereon. It has been found that penetration of metal and/or slag into a tuyere through the upper orifice thereof, which results in permanently blocking the said tuyere, can be prevented effectively by introducing into the tuyere a rod of refractory or non-refractory material which is of the same diameter as, or of a slightly smaller diameter than, the tuyere, the lower orifice of the tuyere being stopped up after the introduction of the said rod into said tuyere It is thus sufficient, for example, to introduce into the tuyere a rod made of metal, refractory material, carbon, graphite, fireproofed or non-fireproofed wood or of any other material and then to plug the lower orifice hermetically; this rod can easily be withdrawn when the converting conditions vary Particularly interesting results are obtained by using wooden rods which can be allowed to burn in the tuyeres after the

sealing plugs are removed. A further sealing method is to combine the sealing plug and the rod, for example, by screwing the rod into the plug. It was also found that penetration of metal and/or slag into the tuyere may be prevented effectively by introducing into the tuyere to be plugged a paste of organic material, or a paste having as its basis a mixture of organic material and refractory material, such as, for example, papier-mache paste or a mixture of papier-mache paste and powdered refractory material, the lower orifice being sealed hermetically after the said paste has been introduced into the tuyere; in this case the tuyere is unstoppered after removal of the plug either by piercing 70 the carbonised residue of the paste by means of a pin, or automatically by combustion of the carbon by the oxygen of the refining gas during the refining of the following charge 75 The application of the aforesaid processes has been found to make possible an increase in the working life of the bottoms In fact convertor bottoms become worn mainly about the tuyeres which are used, and stop 80 ped tuyeres according to the invention have far greater resistance to wear It is thus possible to manufacture bottoms comprising a greater number of tuyeres than is necessary for refining, for example from 30 to 200 ' 85 more than normally required, all the extra tuyeres being plugged according to the methods of the invention After 5, 10 or charges, for example, all or some of the tuyeres which have been operating are plug 90 ged, and an equivalent number of plugged tuyeres are unstoppered This procedure is continued until the bottom is completely worn out. It is also possible to reserve a proportion 95 of the tuyeres for blowing a given gas, other proportions being reserved for other gases. For example the tuyeres at the centre of a bottom can be reserved for an Qr-CQ or O 2.4120 mixture, whilst the tuyeres situated 100 towards the exterior are reserved for blowing ordinary air or oxygen-enriched air, or vice versa In this case it may be of advantage to construct the central part of the bottom either of magnesia or dolomite richer in 105 magnesia than the dolomite normally used. The plugging of the tuyeres according to the invention has nothing in common with plugging by means of refractories, such as has been practised heretofore In fact the 110 traditional method of plugging does not ensure perfect fluid-tightness, since the refractories have always a porosity of between 7 and 40 %, which has the result that cavities are often formed in the tuyeres which have 115 been plugged in this manner; moreover the conventional plugging does not enable the stopped tuyeres to be unplugged at will Due to the hermetic stopping according to the invention the tuyeres can now be plugged 120 and unplugged without risk of cavities forming in the plugged tuyeres.

The application of the invention therefore affords a great number of advantages; it allows rapid change-over from one refining 125 process to another and from one pig iron quality to another without changing the bottom, and yet in each case making an optimum cross-section of blowing available. Thus it is possible, by plugging a number 130 785,810 of tuyeres, to change from ordinary ail i blowing, to blowing with mixtures richer in 1 oxygen, such as 2 Q-120 or 02-CO 2 mixtures and then to change from the latter, to surface blowing after stopping the remainder i of the tuyeres and then return to ordinary air blowing after unplugging the tuyeres I Finally, the invention makes it possible to lengthen the working life of the bottoms. A number of non-limitative examples illustrating the practical application of the method of the invention will now be described with reference to the accompanying drawings, in which:Figure 1 is a sectional view of a convertor bottom, Figure 2 is an enlarged sectional view of the lower part of the bottom shown in Figure 1, and Figures 3 and 4 are views similar to Figure 2 but showing modified bottoms. A steelworks comprising convertors with a capacity of 25 tons of steel normally blows with air enriched to 30 % oxygen, only part of the production being carried out with an Q 0-H,0 or 02-CO 2 mixture When blowing with the air enriched to 30 % 02, the best results are obtained with a total tuyere area of 290 cm 2; when blowing with an 02-H 20 mixture, the optimum tuyere area is 17 G cm 2, or 59 % of the total tuyere area used when blowing with enriched air It will be seen that when blowing with the 02-H 20 mixture, 41 % of the tuyeres thus have to be eliminated. In Figure 1 of the drawings, a convertor bottom has a steel or cast iron base plate A, and refractory material B consisting of dolomite and/or magnesia Open tuyeres C are provided through the plate A and material B and also tuyeres D which are closed by the method of the invention This method consists in hermetically closing the tuyeres by means of plugs E inserted in the lower orifices of the tuyers opening into the windbox, and, where appropriate, introducing into the tuyers either a rod F of wood or of another refractory or non refractory material, or a paste of an organic material or composed of a mixture of organic material and refractory material. In Figure 2 a tuyere D' is shown containing a rod F' made of wood or of a refractory or non-refractory material, and a tuyere D 2 is shown containing a paste F 2 which may or may not be mixed with a refractory material In this Figure the plug E (also marked b) is screwed or crimped directly in the plate A, whereas the plug E (also marked c) is also provided with an intermediate packing H composed of lead,

asbestos, copper, plastic or any other material which can be used to make the gaps gas tight. In the modification shown in Figure 3, 65 Lhe tuyeres D are lined with metal tubes K of copper or steel and jointed with the base plate A in a gas-tight manner by an intermediate packing H which may also be used to fix and render gas-tight the plug E (also 70 marked b) In the case of the plug E (also marked c) however, it is the metal tube K itself which serves as an intermediate packing between the base plate A and the plug E 75 In Figure 4 the convertor bottom A has a plurality of tuyeres D closed simultaneously by the same plug E, screwed or crimped on to or into the base plate. After blowing the desired number of 80 charges with oxygen-steam or 02-CO 2, the plugs are removed and where appropriate the rods are introduced into the tuyeres and blowing is carried out with air enriched with oxygen as previously 85

* Sitemap * Accessibility * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785811 (A)

Description: GB785811 (A) ? 1957-11-06

Improvements in supports for wearing apparel

Description of GB785811 (A)

PATENT SPECIFICATION Inentaor: ARI'STIDE REGUITTI Date of Application and filing Complete Specification: Feb 24, 1956. No 5792/56. V:8 7 8 (Patent of Addition to No668,007, dated March 24, 1950). Complete Specification Published: Nov 6, 1957. Index at acceptance: -Class 141, N 1 A.

International Classification:-A 47 j. COM-PLETE SPECIFICATION Improvements, in Supports for Wearing Apparel We, 'Soc A R L ELLI REGUITTI, a body corporate organised and existing under the laws of Italy, of Rue Renzana 5, Agnosine (Brescia), Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to 'be performed, to be particularly described in and by the following 'statement: - This invention relates to supports for wearing apparel and is an improvement in or modification of that claimed in the parent patent Specification 668,007. The parent patent specification describes an improved support for wearing apparel of the kind comprising, in combination, a portable stand on which jackets and the like can be tidily hung, and a stretcher and presser for trousers or other garments; it claims such a support in which the stretcher and presser comprises a pair of co-acting presser boards one of which is hingedly connected to the support stand at its lower end, the other board being fixed and a spring urgedl clamping plate co-acting with the lower part of the hinged board, characterised in that the clamping plate is so pivotally mounted and constrained as to move as a unit with said presser board towards and away from the fixed presser board but is stopped; in an intermediate position while the hinged presser board completes its opening movement. According to the present invention the outward movement of the movable presser board, which has side bars pivoted to the uprights of the support, is limited by the action of two slotted side links pivoted to said uprights and the slots of which are engaged by pins projecting from the side edges of the movable presser board. By way of example an embodiment of the invention is shown on the accompanying drawing Figs 1, 2 and 31 of the drawing respectively depict a front view, a side view in the open position and a back view of the garment support. Figs 4 and 5 represent cross sections relPnice 3 s 6 d l spectively on the lines A-A of Fig 1 and B-B of Fig 3. The two side elements forming the uprights 1 carrying the fixed presser board 2, are joined at the top by the coat-hanger 3 with or without a tray 4 for the contents of the pockets. The movable presser board 5 has side bars 7 pivoted at 6 to the uprights Slotted links 8 are also pivoted to the uprights, and pins attached to the side edges of the movable presser 'board slidably engage the slots of these links, The purpose of these slotted links 8 is to restrict the outward swing of the movable presser board when it is opened to admit the trousers The already mentioned pivot pins 6 at

the lower ends of the uprights also carry side bars 10 to which is secured a movable cross bar 9 This movable cross bar is biased by ttwo or more springs 11 attached to a fixed cross bar 12 on the presser board 2, By the action of the springs 11, when the movable presser board 5 is swung out in the manner indicated in Fig 5, the cross-bar 9 is caused to move forward into contact with the turnups or cuffs of the trousers placed between the fixed presser board 2 and the movable presser board 5 The maximum angle of swing of the movable cross bar 9 is limited by a pin 13 engaged by one of the side bars, 10 to which the movable cross bar 9 is, secured The upper part of the support described further carries hinged handlest 14 while the movable presser board 5 is provided with co-acting spring catches 15 whereby the movable presser board can be urged towards the fixed presser board 2 in order to press the trousers. The arrangement described and illustrated is susceptible of modification in the details' of construction within, the scope of the invention as defined; by the appended claims.

* Sitemap * Accessibility * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785812 (A)

Description: GB785812 (A) ? 1957-11-06

Improvements in or relating to electric storage batteries

Description of GB785812 (A)

A high quality text as facsimile in your desired language may be available amongst the following family members:

DE1027748 (B) FR1148046 (A) US2857295 (A) DE1027748 (B) FR1148046 (A) US2857295 (A) less Translate this text into Tooltip

[82][(1)__Select language] Translate this text into

The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION Date of Application and filing Complete Specification: Feb 27, 1956. No 6070156. Application made in United States of America on Feb 28, 1955. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 53, B 53 A( 1: 2: 3). International Classification:-H Olm. COMPLETE SPECIFICATION Improvements in or relating to Electric Storage Batteries We, THE l UDYLITE RESEARCH CORPORATION, a Corporation organised and existing under the laws of the State of Michigan, United States of America, of 1651 East (irana Boulevard, Detroit, Michigan, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, tand tie method by which it is to be performed to be particularly described in and by the following statement: - This invention relates to electric storage batteries and more particularly to improvements in the electrolyte of such batteries, including lead storage batteries and the Edison storage battery. According to the present invention an electric storage battery includes, dissolved in the electrolyte thereof, a quantity of at least O 005 grams per litre of electrolyte of a perfluoroalkane sulphonic acid or sulphonate containing 5 to 10 carbon atoms in its molecule. It has been found that the said perfluoroalkane sulphonic acids are stable to the powerful oxidising conditions existing at insoluble anodes during electrolysis of aqueous electrolytes, as for example at lead anodes during the formation of lead dioxide by anodic oxidation None of the wetting agents or surface-active agents commonly available in commerce were found to be stable to the powerful oxidising conditions existing at lead or lead alloy anode surfaces or at the lead dioxide surfaces and the ordinary commercial wetting agents are of very little value The lead dioxide which itself is a powerful oxidising agent is formed or reformed by powerful anodic oxidation when the cell or battery is charged or re-charged It has been found that the compounds used in the present invention are stable not only

to the lead dioxide, but to the even more powerful oxidising conditions existing during charging. The presence in the electrolyte of the surface-active perfluoroalkane sulphonic acid or suiphonate of this invention makes possible low surface tension values and the rapid and complete wetting-out and penetration by the 1 Pdce 3 s 6 d l electrolyte of the spongy lead, lead dioxide, and lead sulphate materials making up the electrodes of the lead cell or battery This aids in decreasing the internal resistance of the cell and increases ithe efficiency of the cell or battery Ordinary surface-active agents on the other hand, because they react with lead dioxide, reduce or " run down " the efficiency of the cell or battery Furthermore, the surface-active perfluoroalkane sulphonic acids of tthe present invention cause a more rapid detachment of any hydrogen or oxygen bubbles (in the form of much smaller or finer bubbles) that may be formed at the cathodes and anodes respectively during electrolysis. The presence of adhering bubbles of hydrogen and oxygen on the cathodes and anodes interferes with uniform formation and conversion of the lead sulphate back to lead dioxide at the anode and lead at the cathode Further, the exceptional wetting-out and penetrating action of the electrolyte containing the surface-active perfluoroalkane sulphonic acids of this invention ensures a slower rate of current decay on the discharge of current from the cell or battery in both new and older batteries, and assists the formation of a finer particle size of lead dioxide during the re-charging. The finer particle size results in an increased surface area of active electrode material in a given cell or battery and brings about an increase in effectiveness of the battery between charges and discharges which in iturn prolongs the time necessary before re-charging of the battery is needed, and in this way also increases the life and efficiency of the battery. Thus these additives are not only desirable for new storage batteries, but also for old ones. The surface-active perfluoroalkane sulphonic acids or sulphonates of this invention decrease appreciably the evaporation of water from the electrolyte especially during warm days and active use, and further have a sequestering or solubilisation effect on certain salts such as those of calcium, ithus decreasing the precipitation of impurities and decreasing Ithe sensitivity of the cell or battery to such 785812 SO impurities (which may become present through impure water additions). Only one addition of a perfluoroalkane sulphonic acid or sulphonate, as defined above, needs usually to be made for the life of the electrolyte of the cell or battery, i e one addition to lower the surface tension of the electrolyte will result in a substantially

constant surface tension value as long as the electrolyte is not lost This arises because the compounds used are substantially stable to all conditions of battery operation and charging Surface tension values as low as 20 or 25 dynes/cm can be obtained with the compounds used in this invention and these values are lower than those obtainable with most commercial surfaceactive agents Actually, the lowest values of surface tension are not necessary to afford improved results, for values even as high as about 60 dynes/cm show improvements over the plain electrolyte which commonly has a surface tension of about 72 to 73 dynes/cm. Thus improvements are obtained with as little as 0 005 to 0 01 grams per litre of n-perfluoroctane 1-sulphonic acid (or its potassium, 25 sodium, ammonium or lithium salt) The useful range of concentrations of the compounds is from about 0 005 grams per litre to saturation Above concentrations of about 8 grams per litre in the cell or battery little additional 30 improvement is obtained except for the lower molecular weight members, that is, those containing five or six perfluorocarbon atoms Perfluoroalkane sulphonic acids containing more than 10 perfluorocarbon atoms are not soluble 35 in the electrolyte whereas those containing less than 5 perfluorocarbon atoms do not produce the desired improvement Preferred compounds for use in the present invention are set out in the following table, together with 40 the preferred range of concentrations of each. TABLE 1) Perfluoro (para methyl cyclohexane) sulphonic acid 2) Perfluore (para ethyl cyclollexane) sulphonic acid 3) Perfluoro iz-heptane 1-sulphonic acid 4) Perfluoro, n-octane 1-sulphonic acid 5) Perfluoro ( 2-cyclohexyl ethane) 1-sulphonic acid 6) Perfluoro cyclohexane sulphonic acid 7) Perfluoro hexane 1-sulphonic acid Mixtures of the above may be employed, such as 0 01 to 02 grams per litre of perfluoro n-octane 1-sulphonic acid with 1 to 2 grams per litre of perfluoro (para ethyl cyclohexane) sulphonic acid The compounds may be added as-the free acids or as sulphonate salts such as the potassium, sodium, lithium or ammonium salts or as organic salts such as the pyridine salt Examp Jes 1 and 2 of the Table foam less in the electrolyte than examples 3 and 4 containing respectively the same number of perfluoro carbon atoms This is important during gassing or during water additions to ithe electrolyte, and the minimum Concentration grams/litre 0.1-6 C 2 F 5 { 3 503 H CF,(CF)65 OH CF,(CF,)75 H -C 2 F 450 i CF,(CF 2),SOH 0.01-2 0.005-1 0.05-3 1-8 1-8 foaming with the lowest surface tension can be obtained with examples 1 and 2 of the Table at not higher than about 1 to 4 grams/ litre concentration Generally compounds containing 6 to 8 carbon atoms are preferred.

The compounds exemplified in the Table are also beneficial and stable in the alkaline electrolyte of the Edison storage cell or battery, and are not lost on standing or on electrolysis of the cell under the highest oxidising conditions and, just as they do not reduce lead dioxide in the lead storage battery, they do not reduce nickelic oxides (Ni Og) or Ni OQ x Hlo. 785,812 C F 3 503 H C-7:785,812 The perfluoiroalkane sulphonic acids used in quantity of at this invention are usually best handled as the perfluoroalka, potassium, sodium, or ammonium salts containing 5 The term " perfluoroalkane sulphonic cule. acids" is intended to mean an alkane sul 2 An elec phonic acid in which all of the bonds of the claim 1 whet carbon atoms except that attached to the sul battery. phonic acid group, are attached to fluorine 3 An elec and ito each other claim 1 whi Another advantage of the use of the corm storage batter pounds of this invention is in suppressing of 4 An elec mist and acid spray from the battery during any of claim use, thereby minimizing corrosion of electrical contains 6 to contacts and leads, besides keeping the acidic 5 An elec mist out of ithe atmosphere claims 1 to

* Sitemap * Accessibility * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785813 (A)

Description: GB785813 (A) ? 1957-11-06

Improvements in or relating to electric circuit arrangements employingtransistors

Description of GB785813 (A)

PATENT SPECIFICATION

Inventor: LEON HENRY LIGHT 785813 Date of Application and filing Complete Specification: March 29, 1956. No 10048/56. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 40 ( 6), T. International Classification:-HO 3 f. COMPLETE SPECIFICATION Improvements in or relating to Electric Circuit Arrangements Employing Transistors We, THE MULLARD RADIO VALVE COMPANY LIMITED, of Spencer House, South Place, Finsbury, London, E C 2, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to electric circuit arrangements employing transistors. In many transistor circuits, signal drive is injected in series with a circuit element or elements providing a source of D C bias. Such element or elements should present a low impedance to signal A C so as to minimise signal loss therein Hitherto, base bias voltage has usually been provided by a separate resistance potentiometer connected across the power supply terminals, in which case the low internal impedance requirement can only be satisfied at the expense of high current drain on the supply source, when the expedient of by-passing the bias source impedance by a large capacitor is not practicable (as in Class B amplifier stages) or is ruled out by considerations of cost. According to the present invention a circuit arrangement comprises at least one thermionic valve, at least one transistor, power supply terminals for the circuit arrangement, a potential divider across said terminals which potential divider comprises the heater of said valve in series with a resistance, and a tapping on said potential divider connected to an electrode of said transistor for applying thereto a fraction of any supply voltage applied across said terminals. Such an arrangement implies a substantial current flow through the potentiometer, but such current does not involve an additional current drain on the supply source since existing heater current is used for bias or like purposes. The voltage fraction appertaining to the transistor electrode may be the fraction corlPrice 3 s 6 d l responding to the resistance, and such voltage fraction may be employed as D C base bias voltage for a junction transistor A signal drive voltage may be applied to the 50 base-emitter section of the transistor in series with the D C bias voltage by means of the secondary winding of a transformer. Preferably the heater of the or each thermionic valve has a resistance

value hav 55 ing a positive temperature coefficient while the reistance in series therewith has a smaller positive or a negative temperature coefficient, the arrangement being such that the voltage appearing across the resistance 60 varies to a lesser extent than changes in voltage at the power supply terminals This feature provides a degree of automatic compensation when the voltage fraction across the resistance, or across a portion thereof, is 65 employed as D C bias for the transistor or transistors. The invention is readily applicable to circuits wherein a plurality of thermionic valves are arranged as amplifier stages for 70 providing signal drive to the or each transistor, the heaters of said valves being arranged in series with each other. A preferred embodiment of the invention will now be described by way of example 75 with reference to the accompanying diagrammatic drawing as applied to a transistor class B push-pull output stage of a batteryoperated signal amplifier or radio receiver. Referring to Figure 1 of the drawing, the 80 output stage comprises junction transistors T 1-T 2 in push-pull, said transistors being in a grounded emitter circuit and having their base-emitter sections driven by a signal transformer 1 The collector load is shown 85 as a winding 2 which may either be the primary of an output transformer or may constitute the actual windings of a loudspeaker or like electromagnetic device. The power supply terminals 3-4 have 90 connected across them a potential divider comprising a series chain of heaters appertaining to valves V 1, V 2,'V 3 in series with a bias resistance R Base bias for the transistors is constituted by the voltage drop across resistance R and the value of such bias may for example, in a practical case, be of the order of 0 16 volts Since the signal drive to the transistors is applied by the secondary of transformer 1 in series with resistance t?, it is importanthat ate value of resistance it be small so as to minimise the loss o& gain This in turn implies a relatively large current flow through resistance R, but such current does not involve an additional current drain on the supply battery since existing heater current is used for bias purposes in accordance with the invention. Moreover, as explained above, since the heaters of valves V 1-V 3 have a positive temperature coefficient, changes in battery supply voltage will be accompanied by changes in the potential divider ratio between resistance R and the heater chain so that the resultant voltage drop across PR will tend to remain constant in spite of the running down of the supply battery or variations between one battery and another In Fact, the bias voltage can be maintained more constant by this arrangement than with the use of a separate loaded bias battery, and

this is particularly true in the case of the very low base bias voltage values required for transistors. Tile high degree of consistency in base bias voltage is, of course, required to maintain the transistors at the selected operating point of their characteristics so that distortion is minimised. The valves V 1-V 3 may be employed in any appropriate manner, for example in a superhetrodyne circuit providing audio signals to the transformer 1, but the actual circuitry of valves V 1-V 3 has not been shown since it is not relevant to the invention However, in a convenient example, the heaters of the valves may be 1 5 volt heaters in which case the power supply for the whole system may be a 4 5 volt battery supplying the collector voltage and also supplying the heater and bias resistance series chain. In a variant of the circuit illustrated, stabilisation of the mean emitter current of the transistors may be provided in known manner by a resistance in the emitter circuit. Since the bias voltage is more constant than the power supply, the mean emitter current value is more constant when this form of stabilisation is used in a circuit according to the invention than is the case with other circuit arrangements. If directly-heated valves are used, signal currents flowing through the bias resistance will cause a signal voltage to appear between the control grid of a valve and the mid-point of its filament if the grid return is connected to a point at fixed potential or to a point on the heater current circui This defect is usually not serious, 'out the following means may be used to prevent signail vohta es ironm being fed bachas to tue or eaci co-itro '-rid. The conirol giid mlay b e crinected to an 70 artificial centre-tap provided across t G f;alernt fo" signal voltitges uit S O ot -Or 9 C. vo frge S o SE-e Ordie vr in G shows such a centre-tap provided at F; a potential divider R 3 hang a serves capacil 75 tor C 'or D C bloc'in purposes. What we clril is:1 A circuit arraemeri comprising at least one thermionic at leas one transistor, power supply 'er Orrals f t 1 e circuit 80 arrangement, a potential 01 vider across said terminals which potential divider comprises the hleater of said valve in series with a resistance, and a tapping ola said po L ntial divider connected to an electrode o said 85 transistor for applying thereto a fraction of any supply voltage applied across said terminals. 2 A circuit arrangement according to

* Sitemap * Accessibility * Legal notice

* Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p