DESC:FIELD OF INVENTION

The present invention relates to leak testing of machined components. In particular, the present invention relates to the testing of expansion plugs. More particularly, the present invention relates to leak testing of expansion plugs and the like by using a compressed air based vacuum operated leak-testing system.

BACKGROUND OF THE INVENTION

Current hydraulic systems generate vacuum, which is used for leak testing of the expansion plug. The drive, e.g. an electric motor runs continuously to generate vacuum. Leak test is an integral part of the process in engine assembly. The expansion plug leakage is tested by means of a vacuum operated leak-testing machine.

DISADVANTAGES WITH THE PRIOR ART

However, the problem with the conventional arrangement is that the vacuum is generated by means of an electrical oil pump arrangement. In this arrangement, the leakage rate is compared by using a mercury column. The following major disadvantages have been noticed with the conventional hydraulic system based electrical oil pump arrangement for vacuum generation to carry out leak testing of the machined components/systems. These disadvantages are briefly discussed above:

? Mercury is a hazardous material.

? Oily area due to oil pump generating the required vacuum is risky.

? Cause mechanical damages due to continuous rotation.

? Consumes substantially higher power.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a cost-effective vacuum generating arrangement for leak-testing of the machined components/systems.

Another object of the present invention is to provide an energy-efficient vacuum generating arrangement for leak-testing of the machined components/systems.

Still another object of the present invention is to provide a vacuum generating arrangement for leak-testing of the machined components/systems having least mechanical wear and tear.

Yet another object of the present invention is to provide a vacuum generating arrangement for leak-testing of the machined components/systems, which is simple to manufacture.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE INVENTION

In order to save power, it is proposed to switch over to an air-based (pneumatic) vacuum generating system instead of the conventional hydraulic-based vacuum generating system. In this pneumatic system, the vacuum generator works on the venturi principle.

Accordingly, the vacuum generator generates vacuum to be used in the pressure gauge of this pneumatic system to detect the presence of leaks, if any, in the machined components/system, e.g. expansion plugs. The receiver nozzle in turn generates vacuum at the output (vacuum) port.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an air-operated vacuum generating system for leak-testing of components and/or assemblies, wherein the system comprises:

• an air-inlet chamber connected to compressed air supply;

• an air-outlet chamber connected to a receiver nozzle via a 3/2 valve and a pressure switch;

• the air-inlet chamber and air-outlet chamber connected via a substantially straight passage disposed centrally within the system;

• at least one profiled-nozzle disposed on the central air-passage and located between the air-inlet and air-outlet;

• at least one port connected laterally to the central air-passage; and

wherein the outlet of the profiled-nozzle is close to the point of entry of air through the laterally connected port into the straight passage.

Typically, the profiled-nozzle is configured as a jet (venturi) nozzle.

Typically, the point of entry of air through the laterally connected port outlet is disposed between the outlet of the nozzle and a funnel shaped cavity configured downstream the nozzle.

Typically, the funnel shaped cavity creates a suction effect or vacuum to pull more air from the laterally connected port to further accelerate the compressed air passing through the straight passage.

Typically, the nozzle is configured to increase the speed of the compressed air up to 5 times the speed of sound while passing through the nozzle.
Typically, the 3/2 valve is provided to maintain the vacuum within a specified limit, which is displayed by pressure switches.

Typically, the system adjudges the component / assembly under leak-test to be leak-free and thereby suitable for further processing, if the pressure switch indicates the presence of the vacuum remains and no air-release is observed for about 7 seconds.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings.

Figure 1 shows the air (pneumatic) based vacuum generating arrangement configured in accordance with the present invention.

Figure 2 shows the vacuum leak testing machine configured in accordance with the present invention and using the arrangement of Fig. 1

Figure 3 shows an enlarged perspective view of the portion encircled in Fig. 2.

Figure 4 shows a pressure switch for detecting vacuum value by measuring the pressure of the exiting air.

DETALED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 shows the vacuum generating arrangement is configured in accordance with the present invention as the ejector arrangement 10 consisting of a jet (venturi) nozzle 4 and at least one receiver nozzle 30 (not shown) based on the design principle thereof. For generating vacuum, the compressed air 2 enters the ejector arrangement 10 (on the left side in this figure) and passes along the straight path 8 shown by arrows provided across the jet (venturi) nozzle 4. Just after the jet (venture) nozzle 4, a funnel shaped cavity 6 is provided. Air 12 is sucked through a port 14 laterally connected to the straight path 8 configured within the vacuum generating ejector arrangement 10. The compressed air 16 exiting the jet (venturi) nozzle 4 creates a vacuum around the funnel 6, which thereby pulls air 12 through port 14 and subsequently pushes the compressed air 16 exiting the jet (venturi) nozzle 4 in order to accelerate the compressed air speed up to 5 times the speed of sound as it flows through the jet (venturi) nozzle 4. There is a short gap 18 provided between the exit from the vacuum generating ejector arrangement 10 and the entry in the receiver nozzle 20 (on the right side of this figure). The compressed air 2’ expanded by the jet (venturi) nozzle 4 creates a suction effect at the gap 18 towards the receiver nozzle 20, which in turn creates a vacuum at the output (vacuum) port (not shown). As the vacuum is generated, a 3/2 valve is provided to hold the vacuum within a specified limit, which is displayed by pressure switches. If the vacuum remains and no air-release is observed for about 7 seconds, the system adjudges the expansion plug to be leak-free and indicates that the part is OK.

Figure 2 shows the vacuum leak testing machine configured in accordance with the present invention. The encircled portion 50 shows the ejector arrangement 10 used for generating vacuum (see Fig. 1).

Figure 3 shows an enlarged perspective view of the encircled portion 50 of Fig. 2. The vacuum leak testing machine configured in accordance with the present invention uses a vacuum generating ejector arrangement 10 according to Fig. 1. The encircled portion 50 shows the major change by using the vacuum for generating vacuum (see Fig. 1).

Figure 4 shows a pressure switch for detecting vacuum value by measuring the pressure.

The air-based (pneumatic) vacuum generating system is proposed in accordance with the present invention, which has the following technical and economic advantages:

• No use of mercury, so hazards are eliminated by using air to be used as vacuum generating vacuum.
• Uses very simple logic, making it easy to understand.

• No hydraulic pump is used, thus maintenance is easy.

• Substantial reduction in energy or power consumption.

• Due to absence of rotating parts, the mechanical breakdown eliminated.

• Uses a very simple circuit.

• Initial investment is substantially reduced to Rs. 8.5 lacs as against the earlier cost for conventional hydraulic system which costs manifold.

• Substantial savings in the operating costs, which are as low as Rs. 1.0 lac / annum.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

A person skilled in the art may make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention.

Although the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily modifications recognize that these embodiments can be applied with possible within the spirit and scope of the present invention as described in this specification.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. ,CLAIMS:We claim:

1. An air-operated vacuum generating system for leak-testing of components and/or assemblies, wherein the system comprises:

• an air-inlet chamber connected to compressed air supply;

• an air-outlet chamber connected to a receiver nozzle via a 3/2 valve and a pressure switch;

• the air-inlet chamber and air-outlet chamber connected via a substantially straight passage disposed centrally within the system;

• at least one profiled-nozzle disposed on the central air-passage and located between the air-inlet and air-outlet;

• at least one port connected laterally to the central air-passage; and

wherein the outlet of the profiled-nozzle is close to the point of entry of air through the laterally connected port into the straight passage.

2. Vacuum generating system as claimed in claim 1, wherein the profiled-nozzle is configured as a jet (venturi) nozzle.

3. Vacuum generating system as claimed in claim 1 or 2, wherein the point of entry of air through the laterally connected port outlet is disposed between the outlet of the nozzle and a funnel shaped cavity configured downstream the nozzle.

4. Vacuum generating system as claimed in anyone of the claims 1 to 3, wherein the funnel shaped cavity creates a suction effect or vacuum to pull more air from the laterally connected port to further accelerate the compressed air passing through the straight passage.

5. Vacuum generating system as claimed in anyone of the claims 1 to 4, wherein the nozzle is configured to increase the speed of the compressed air up to 5 times the speed of sound while passing through the nozzle.

6. Vacuum generating system as claimed in anyone of the claims 1 to 5, wherein the 3/2 valve is provided to maintain the vacuum within a specified limit, which is displayed by pressure switches.

7. Vacuum generating system as claimed in anyone of the claims 1 to 6, wherein the system adjudges the component / assembly under leak-test to be leak-free and thereby suitable for further processing, if the pressure switch indicates the presence of the vacuum remains and no air-release is observed for about 7 seconds.

Dated: this day of 30th April, 2015. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT