Title of Invention	"A PROCESS FOR THE PREPARATION OF A PERFORATED ADDITIVE LINER FOR REDUCING GUN WEAR"
Abstract	This invention relates to a process for the preparation of a perforated additive liner for use with combustible cartridge cases for reducing gun wear. According to the process a talc-wax mixture is prepared by mixing powdered talc (hydrated magnesium silicate), wax mixture and stearyl alcohol. The talc-wax mixture is coated on gauge cloth and the additive liner is perforated.

Full Text

FIELD OF INVENTION The present invention relates to a perforated additive liner for use along with Combustible Cartridge Case (CCC) Ammunition, for improving barrel life by reducing the gun wear. PRIOR ART To save precious metal (lie replacement of costly brass cartridge case by Combustible Cartridge Case (CCC), in high calibre gun Ammunition has been in vogue. This replacement of brass cartridge case with CCC, saves manufacturing effort and reduces overall production cost while saving precious metal. With the increased demand of high performance of guns which deliver ammunition at very high muzzle velocity, use of high impetus propellant has become necessary. While the brass cartridge cases protected the inside of gun from the action of flame, in the present scenario this changeover to CCC has not been very satisfactory. The high flame temperature of the charge, increases gun barrel temperature, reducing number of round that can be continuously discharged per cycle-round, to allow the gun to return to ambient temperature. This high increase of barrel temperature, causes pitting of the gun inside. The unburned residue of the CCC also adversely effects the gun life, and during conflict, exposes the gun location by discharge of unburned CCC particles and muzzle flash, which are thrown out in the open-air alongside the projectile. The aforesaidi drawbacks has been the major reason for the reduction of useful life of guns, which are necessarily caused by the action of solid . propellant, which is highly reactive, coming in direct contact with the inside of the gun material at very high temperature and pressure. Weapon designers have tried to resolve this problem by adopting different approaches, such as barrel material modification, use of low flame temperature propellant and the use of wear reducing additives. The phenomenon of barrel erosion is attributed to, chemical and mechanical effects. The effect of barrel erosion by thermal means is controlled by the use of wear reducing additives. Prominent among the wear reducing materials being used for the purpose are titanium dioxide,. Talc and polyurethane. One of the additive composition known in the art comprises of A7. sodium or potassium water glass end flash suppressant volatile admixture, which is placed adjacent to every props11ant grain charge by way of coating or the additive composition is alternatively applied on a combustible case, for reducing muzzle flash and reduce gun erosion. The main disadvantage of above additive composition is that it has an adverse effect on the range of projectile due to reduce prope11ant charge to accommodate additive mixture, and that the proper configuration and homogeneity is difficult to achieve. Yet another disadvantage is that sublimation occurs even at room temperature which causes loss of flash reducer. Another composition known in the art incorporates one of the erosion and flash additives like TiO.sub.2, talc, K.sub.2 SO.sub.4, KNO.sub.3 on a wax cloth lin*r. The main drawback of above composition is that initially the flames do not directly come in contact with CCC, this leaves some unburned residue of the CCC at the time of projectiles emergence from the gun barrel, which adversely effects the gun life. Another drawback of such a composition is that throwing out of unburned CCC particles during firing .and muzzle flash ex pose's the gun location. OBJECTS OF THE PRESENT INVENTION The primary object of the presont invention is to provide a perforated udditlve liner treated with a composition involving mixture of hydrated magnesium silicate (laic), Max and stearyl alcohol (referred to hereafter in this specification a« 'wax—talc' treated perforated additive liner) and wax for use with CCC in high caliber tank qun ammunition for reducing gun wear. Another object of the present invention is to provide a wax—talc treated perforated additive liner which regulates exposure of the CCC to the high temperature flame produced by the prope11ant, by way of perforations in the coated liner media and also ensures complete burning of CCC inside the gun barrel. Still another object of the present invention is to provide » wax-talc treated perforated additive liner for use with CCC in high caliber tank gun ammunition which is completely reliable. Further object of the present invention is to provide a wax—talc treated perforated additive liner for use with CCC in high caliber tank gun ammunition which minimises the contact of flame at high temperature with gun barrel thereby reducing the degradation of barrel inside due to transfer of thermal energy. Yet further object of the present invention is to provide a wax—talc treated perforated liner for use with CCC in high caliber tank gun ammunition which prevents delayed or incomplete combustion of CCC, and leaves no CCC residue inside gun barrel so that the barrel inside does not get coated with the residue. SUMMARY OF INVENTION According to this invention there is provided a process for the preparation of a perforated additive liner for use with combustible cartridge cases for reducing gun wear which comprises in the steps of i- (a) preparing a talc-wax mixture by mixing powdered talc (hydrated magnesium silicate), Max mixture and stearyl alcohol, (b) coating said talc-wax mixture on gauze cloth, (c) perforating the additive liner. In accordance with the present invention, •the perforated additive liner comprises of a coated substrate fabric material such that it does not obstruct the propel1 ant flame from reaching the CCC while the coating on the liner provides wear/erosion reducing factors. There is also means for quenching heat, produced by the propellant mix, which is provided by an additive to the liner. The additive is comprised of wax—talc mixture and does not leave any residue after burn—out. Talc—wax mixture is uniformly coated on cotton gauze cloth and is then placed between th» propellant bed and CCC. During the combustion of propellant these wear reducing materials form a laminar cool layer between the hot gases and the inside of gun barrel, thereby reducing transfer of heat to the gun barrel. In operation the liner need only be placed proximate to said propellant and vicinal to the base of said projectile. Additionally the liner may be located within a propelling charge container, preferably. Maid liner is located juxtaposed to the said propelling charge container and said propellant which are proximate and in communication with the inside of th* gun barrel. The present invention will now be described in detail and illustrated with reference to an example which is intended to be a typical example to illustrate the working of the invention and is not intended to imply any limitation on the scope of the present invention. PREPARATION OF LINER The process of preparation of perforated liner comprises of the following steps :-a) Preparing a mixture of 45 to 55% powdered talc (hydrated magnesium silicate (3MgO, 48 i(^ , H^ O) of 2 to 3 micron particle size and wax mixture (of slip point not less than 75 C) 45 to 55% VAX (of slip point not less than 75 C with stearyl alcohol 1 to 2%). b) Coating of talc VAX mixture on on* Bide of gauze cloth to uniform thickness of 0.8 to 1.00 mm. c) Cutting the coated sheet to the required size, to avoid overlapping while fixing on the internal surface of the CCC. d) Perforating the additive liner to realize perforation size 2.5 to 3.00 mm diameter, adjusting the perforation in such a May that alternate line of perforation Mill fall in the same line and that the distance between periphery of two adjacent holes is maintained at 6 to 7 mm apart (Fig. 1). APPLICATION OF LINER; Fixing of the additive liner to the CCC inside surface is done with the help of any suitable flaiMMble adhesive cement (known in the art) applied on the side not coated with talc-wax composition. This adhesive is of the type that does not leave any residue after burning. The size of the liner is adjusted to just, cover the inside of CCC without overlap. In operation* the liner need only be placed proximate to said propellant and vicinal to the base of said projectile.Additionally the liner may be located within • propelling charge container, preferably, said liner im located juxtaposed to the said propelling charge container and said propellant which are proximate and in communication with the inside of the gun barrel. DESCRIPTION OF FIGURES The embodiment of the present invention will be more clearly understood from the accompanying drawing which depicts as follows i — Fig. 1 Shows the front view of the perforated additive liner WORKING EXAMPLE 1.0 kg of paraffin wax, 1.5 kg of macrocrystalline wax and 0.15 kg of stearyl alcohol are weighed and transferred to electrically heated bath and heated to molten condition (temperature 100 degree celsius approx.). The molten wax is homogenised and to this 2.5 kg of talc (particle size 2-3 microns) is added. TNt mix is stirred to form a uniform and homogenised mix. The mix is kept in hot condition. To thi* mix, approx. 6 sq. meter of gauze cloth is passed to form a uniform coating on both sides of the gauze cloth. The coated gauze cloth is passed through rollers to ensure uniform spread and as well as to adjust the thickness of coating to 0.8 to 1.0 mm. The coated gauze cloth is then allowed to cool. Additive liner sheets cut to size arm then perforated as per the description given above. Weight of each additive liner is adjusted between 122 to 132 g. It is to be understood that the above description of the present invention is susceptible to considerable modification, change and adaptation by those skilled in the art. Such modification, adaptation and change arm intended to be considered to be within the scope of the present invention which is set forth by the following claims. WE CLAIM; 1. A process for the preparation of a perforated additive liner for use with combustible cartridge cave* for reducing gun wear which comprises in the steps of I — (a) preparing a talc-wax mixture by mixing powdered talc (hydrated magnesium silicate), wax mixture and stearyl alcohol, 2. A process as claimed in claim 1 wherein pondered talc is present in an amount of 45 to 55 parts. 3. A process as claimed in claim 1 wherein said powdered talc is preferably of 2 to 3 micron size. 4. A process as claimed in claim 1 wherein the slip— o point of wax mixture is not less than 75 C. 5. A process as claimed in claim 1 wherein Max- mixture is present in an amount of preferably 45 to 95 parts. 6. A process as claimed in claim 1 wherein strearyl alcohol is present, in an amount: of preferably 1 to 2 parts. 7. A process as claimed in claim 1 wherein the thickness of wa>:-talc coating on the gauze cloth it preferably 0.8 to 1.0 mm. 8. A process as claimed in claim 1 wherein maid perforation of coated gauze cloth is preferably of 2.S to 3.0 mm diameter. 9. A process as claimed in claim 1 wherein distance between the periphery of two adjacent holes i* 6 to 7 mm. 10. A process for the preparation of a perforated additive liner for a use with combustible cartridge cases for reducing gun wear substantially as described herein.

Documents:

281-del-2000-abstract.pdf

281-del-2000-claims.pdf

281-del-2000-correspondence-others.pdf

281-del-2000-correspondence-po.pdf

281-del-2000-description (complete).pdf

281-del-2000-drawings.pdf

281-del-2000-form-1.pdf

281-del-2000-form-19.pdf

281-del-2000-form-2.pdf

281-del-2000-form-3.pdf

281-del-2000-gpa.pdf