FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
PROVISIONAL /COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
A novel device for proof pressure testing.

2. APPLICANT
(a) NAME : Larsen &Toubro Limited
(b) NATIONALITY : Indian Company registered under the provisions of
the Companies Act,1956
(c) ADDRESS : L & T Hose, Ballard Estate, Mumbai 400 01.
Maharashtra State, India.
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL COMPLETE
The following specification describes the The following specification
invention. particularly describes the invention and the manner which it is to be performed.


Technical Field:
The present invention "a novel device for proof pressure testing" relates to a device for simulated testing of rocket motor casings wherein a floating-piston mechanism is used to simulate the launching conditions. The pressure generated inside the casing during testing is subsequently passed on to and absorbed by a simple pressure-bearing structure.
Background and Prior Art:
In the Aerospace industry, manufacturers need to test the rocket motor casings after manufacturing to check whether they would work in the desired fashion during actual use i.e. launch of the rocket. To do that, a simulated testing is performed such that the same conditions are present as they would be during the actual launch of the vehicle in use. One of the typical requirements in this exercise is to create & release pressure in such a way that would simulate the conditions of actual use where the fuel is ignited and the resultant gases emit from the bottom-end of the rocket causing the launch of the vehicle. During the actual launch the gases emit from a central opening at the bottom of the motor casing. Hence the challenge (during testing) is to block the opening, create the calculated pressure and then release it using a mechanism that allows the release of pressure so as to simulate & restrict the pressure and stresses created on the bottom-end to the same level as expected during the actual flight. This testing is very important since such casings are designed with a safety factor of only 10% such that the weight of the casing can be kept at the minimal level.
Typically a floating-piston mechanism is used for the above-said purpose of holding the pressure up to a pre-defined limit and then the same getting released rapidly. This outward movement of the piston


needs to be then arrested free of the bottom-end so that the piston does not actually shoot out from the opening.
Hitherto, this arresting function is served by some kind of a solid construction erected against the above-said opening where the said floating-piston is deployed. The construction consists of concrete structures that are designed to withstand the typical pressure generated during the above-said testing. The structures are of two types -horizontal construction or vertical construction. A schematic diagram of each of these types of testing facility is depicted in Figures 1 & 2. Where arrows show direction of pressure.
Since the pressures generated in the above-said testing are very high, in both the types of construction a very rigid & strong structure is required. This typically involves concrete foundation several meters deep under the ground and also suitable dimensions of the pillars that are the direct members bearing the pressure transferred via the floating-piston. As such one has to engage into an elaborate, voluminous and costly activity to build and operate with such structures to carry out the above-said testing.
The industry therefore would be benefited greatly if a simpler, more compact and less costly arrangement is provided to carry out the above-said testing.
Drawbacks of Prior Art:
1. The prior art devices used to carry out the simulated testing of rocket motor casings involve construction of elaborate, costly and space-consuming concrete foundations and structures.


2. The above-mentioned devices of prior art are difficult to operate with and are not portable.
Objective of present invention:-
The object of the present invention is to have a device to avoid large monetary investment and the construction activity involved in building concrete foundations and structures for carrying out the above-said testing.
It is a further object of the invention to provide for a device that serves the purpose and at the same time is simpler to operate, occupies lesser space and is portable.
Summary of the Present Invention:
In accordance with the present invention "a novel device for proof pressure testing.", instead of having a pressure-bearing construction on outer sides of the rocket motor casing being tested, a tension-bearing member is used inside of the said rocket motor casing test cover. A floating-piston is deployed at one end of the tension-bearing member and the other end is secured to the inside of the said rocket motor casing test cover. The pressure is built by pumping in oil inside the casing taking the floating-piston upwards with it till such time as the floating-piston protrudes out of the central opening. As the pressure builds up further the same is absorbed in the form of the tension borne by the said tension-bearing member. Description of figures:-
Fig. 1 shows horizontal construction of concrete structure that is designed to withstand the typical pressure generated during the testing.


Fig. 2 shows vertical construction of concrete structure that is designed
to withstand the typical pressure generated during the above-said
testing.
Fig. 3 shows construction of preferred embodiment of present invention
device for proof pressure testing.
Description of the Present Invention:
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the preferred embodiment.
Device & method of the Present invention:
The device & method of this invention in its preferred embodiment has a construction as depicted in Fig 3 and is explained below. Present invention "a novel device for proof pressure testing" comprises of rocket motor casing (1), central opening (2), tension-bearing member (3), fixtures (4), telescopic elements (5), floating-piston (6) wherein the said rocket motor casing (1) being tested is placed in a vertical position with its end with the central opening (2) on top. A tension-bearing member (3) is secured to the inside bottom portion of the said testing cover of the rocket motor casing (1) using fixtures (4). The said tension-bearing member (3) has a telescopic construction such that when it is pulled upwards by some force it extends in length till such stage that all the telescopic elements (5) have fully stretched out. A floating-piston (6) is attached to the top end of the said tension-bearing member (3). Thus the mechanism functions as a flexible expanding-collapsing arrangement as the oil is filled up inside the casing during testing, eventually exercising a tension on the tension member (3) thus preventing the


floating-piston (6) from being shot out of the opening, while at the same time serving the purpose of simulating the conditions for the desired testing to be carried out on the said rocket motor casing. Advantages of the Present Invention:
The present invention is advantageous in that -
1. the manufacturers need not make large investments of money & efforts in constructing solid concrete foundations and structures for the purpose of bearing the pressure transferred out via the floating-piston;
2. the arrangement saves space, is easily portable & simpler to operate compared to the similar testing facilities used hitherto.
Salient Features of the Present invention:
1. The device deploys a tension-bearing member inside the rocket motor casing being tested instead of a pressure-bearing structure on outer sides of it.
2. The device uses a telescopic construction for the above-said tension-bearing member thus making the mechanism very easy to operate, making it easy to transport and install & remove.
3. The device is less costly and occupies lesser space than the other available devices of the prior art.