A) TECHNICAL FIELD
[0001] The present invention generally relates to energy meters and particularly it relates to optical reading system in electronic energy meters. The present invention more particularly relates to a sealing system for optical port in electronic energy meters.
B) BACKGROUND OF THE INVENTION
[0002] An energy meter is a device that measures the amoimt of electrical energy produced in a power station or supplied to a residence, business establishment or machines. The most common type is known as a kilowatt hour meter or joule meter. When used in electricity retailing, the device records the values measured by these meters to generate a billing for the electrical power consumed. It also provides other parameters like maximum demand with date and time, kWh backups etc.
[0003] The most common type of electricity meter is the electromechanical induction meter. The electromechanical induction meter operates by counting the revolutions of an aluminum disc which is made to rotate at a speed proportional to the power. Thus the nimiber of revolutions of the disc is proportional to the energy used.
[0004] Some of the electricity meters are solid state type and they display the power used on an Liquid Crystal Display (LCD) module, while the electronic meters can be read automatically. In addition to measuring the consumption of the electricity, the

solid state meters may also record other parameters of the load and supply such as maximum demand, power factor and reactive power used etc. They may also include the electronic clock mechanisms to compute a value, rather than an amount, of electricity consumed, with the pricing varying of by the time of day, day of week, and seasonally.
[0005] The reading of electrical-energy meters has historically been accomplished with human meter readers who visit customers' premises and manually document relevant information from the meter. Over the period of time manual meter reading has been enhanced or eliminated through the use of meter reading systems. The disk rotation in the meter is typically sensed by optical devices. These optical sensors create pulses for each rotation of the disk or by detection of disk shaft movement. Thus the measured pulses correspond to the electrical energy consumed.
[0006] In a meter reading system, a probe is held in proximity to communicate with the meter to acquire the data collected by the meter. The information between an electrical-energy meter and a probe or other external device may be exchanged by two-way, optically isolated communication system. In such cases, the electrical-energy meter will have an optical port provided with an optical transmitter and an optical receiver to communicate respectively with the optical receiver and optical transmitter provided in the external device.
[0007] In general, the electronic meters are equipped with optical port having infrared (IR) sensors. To avoid tampering/unauthorized access to these ports, a general sealing arrangement is provided on every meter. According to the sealing arrangement, the

optical port is closed with a cover that can be sealed with the help of sealing wire. A general requirement of sealing provision is that it should provide a physical evidence of tampering, when the sealing cover is tampered. However most of the sealing mechanisms provided by different manufacturers are not capable of providing the evidence for tampering.
[0008] The currently available prior art methods provide sealing arrangements in which the washer used for sealing meters can be easily removed and put back thereby yielding a major disadvantage. Most of the times, the operator may leave the optical port open due to the shortage of the washer or the operator may forget to replace the washer back. In some cases the washer may fall back. In that case any one can access the optical ports of the energy meter which may cause accidents or may result in tampering of the meters.
[0009] Currently available optical port sealing systems do not provide a fool proof sealing mechanism and the evidence incase of tampering. Hence there is a need to develop a foolproof sealing mechanism for optical port in energy meters to prevent the tampering or unauthorized access to the optical ports.
C) OBJECTS OF THE INVENTION
[0010] The primary object of the present invention is to develop an optical port sealing system for electronic meters to prevent the tampering of the optical port and to provide a physical evidence of tampering.

[0011] Another object of the present invention is to develop an optical port sealing system provided with a permanently fixed sealing feature on an optical port in electrical meter so that the sealing feature cannot be restored upon tampering with out any physical damage.
[0012] Yet another object of the present invention is to provide an optical port sealing system provided with a spring loaded sealing cover to close the optical port in the energy meters in unused condition thereby preventing the accidental access to the optical port in unused condition.
[0013] Yet another object of the present invention is to provide an optical port sealing arrangement for energy meters to avoid unauthorized access to the optical ports.
[0014] Yet another object of the present invention is to provide an optical port sealing system provided with a spring loaded sealing cover to close the optical port in the energy meters in unused condition so that the sealing cover may be opened only by inserting the optical probe.
[0015] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION
[0016] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

[0017] The various embodiments of the present invention provide an optical port sealing system for energy meters, arranged with a sealing feature which is fixed permanently to the top cover of the energy meter and which cannot be restored to the top cover without any physical damage after the tampering of the sealing system. The sealing system includes a spring loaded sealing cover to close optical ports in unused condition thereby preventing the accidental access to the optical port in unused condition.
[0018] According to one embodiment of the present invention, the optical port sealing system has a sealing assembly mounted on the top case of the energy meter. The sealing assembly has a base formed integrally with the top case to receive and store an opaque sealing cover and a metallic washer such as a mild steel washer. The base has slot to receive the springs provided in the back of the sealing cover. The base has projections which are inserted into the holes provided in the metallic washer and are deformed by applying a heat treatment process to hot seal the metallic washer to the base. The base also has a sealing projection for sealing the sealing cover using a sealing wire. The sealing projection has hole which is aligned with the sealing hole provided in the sealing cover and a sealing wire with a lock mechanism is inserted into the holes to seal the locking of the sealing cover with the base.
[0019] The sealing cover has holes to permh the access to the Light Emitting Diodes (LED) provided in the energy meter. Under normal conditions such as the unused condition, the holes in the sealing cover are not aligned with the LEDs in the energy meter thereby preventing access to the LEDs. The sealing cover is provided with

spring loading mechanism at the back side so that the sealing cover is moved along with an Optical Reading Head (ORH) to enable the Infra Red (IR) LEDs provided in the ORH to communicate with the LEDs provided in the energy meter when the ORH is inserted into the sealing cover. The sealing cover falls back to close the LEDs in the energy meter to prevent the access to the LEDs when the ORH is removed. The sealing cover has T-shaped projection which is pushed by the ORH in the inserted condition so that the sealing cover moves along with the ORH to align the holes with the optical port to make the LEDs of the energy meter to conmitmicate with the IR LEDs of the ORH to transfer the data from the energy meter to the ORH. The sealing cover has a sealing projection provided with a hole so that the hole in the sealing projection provided at the base and the hole in the sealing projection provided at the sealing cover are aligned to receive a sealing wire with a locking mechanism. The sealing wire with the locking mechanism are passed through the holes in the sealing projections in the base and in the sealing cover to seal the locking of the seal cover with the base in the assembly, after mounting the sealing cover on the base.
[0020] The metallic washer has holes formed in the periphery to receive the projections provided in the base for hot sealing the mild steel metallic washer with the base in the sealing assembly. The projections in the base are inserted into the holes at the metallic washer and deformed by using a heat treatment process. The metallic washer is provided with slot which is aligned with the holes in the sealing cover to permit access to the LEDs in the energy meter, when the ORH is inserted. In the unused condition, the slot is not aligned with the holes in the sealing cover. The metallic washer has a cut recess at the periphery to receive and facilitate the movement of the T-projection formed in the sealing cover so that the sealing cover is

moved to align the holes in the sealing cover with the slot in the metallic washer to permit the access to the LEDs in the energy meter, when the ORH is inserted. The metallic washer is formed in such a manner that the metallic washer will be physically damaged during the tampering of the sealing assembly and the metallic washer can not be replaced without damage during the replacement.
[0021] Thus the sealing system of the present invention prevents unauthorized or accidental access to the optical ports in the energy meter and the sealing system can not be restored up on a tampering event without receiving a physical damage.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0023] FIG. 1 shows an exploded perspective view of the optical port sealing system for energy meter according to one embodiment of the present invention.
[0024] FIG. 2 shows the exploded and assembled perspective views of the sealing cover in the optical port sealing system for energy meter according to one embodiment of the present invention.

[0025] FIG. 3 illustrates an exploded view and the assembled view of the sealing cover and the top case in the optical port sealing system for energy meter according to one embodiment of the present invention.
[0026] FIG. 4a illustrates an exploded view of the mild steel washer and the top case with sealing cover assembly in the optical port sealing system for energy meter according to one embodiment of the present invention.
[0027] FIG. 4b illustrates the assembled views of the mild steel washer and the top case with sealing cover assembly, before and after a hot sealing process, in the optical port sealing system for energy meter according to one embodiment of the present invention.
[0028] FIG. 5a illustrates the perspective and enlarged top plan views of an optical port sealing system for energy meter according to one embodiment of the present invention before inserting the optical reading head assembly.
[0029] FIG. 5b illustrates the perspective and enlarged front plan views of an optical port sealing system for energy meter according to one embodiment of the present invention with the inserted condition of the optical reading head assembly.
[0030] FIG. 5c illustrates the perspective and enlarged plan views of an optical port sealing system for energy meter according to one embodiment of the present invention after the removal of the optical reading head assembly.

[0031] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0032] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0033] The various embodiments of the present invention provide an optical port sealing system for energy meters. The system provides a permanently fixed sealing feature on the energy meter, which cannot be restored upon tampering without any physical damage. It provides a simple assembly to seal the optical ports in the energy mete. The sealing system includes a spring loaded sealing cover to close optical ports in unused condition thereby preventing the accidental access to the optical port in unused condition.
[0034] According to one embodiment of the present invention, the optical port sealing system has a sealing assembly mounted on the top case of the energy meter. The

sealing assembly has a base formed integrally with the top case to receive and store the sealing cover and a metallic washer such as a mild steel washer. The base has slot to receive the springs provided in the back of the sealing cover. The base has projections which are inserted into the holes provided in the metallic washer and the metallic washer is hot welded to the base. The base also has a sealing projection for sealing the sealing cover using a sealing wire. The sealing projection has hole which is aligned with the sealing hole provided in the sealing cover and a sealing wire with a lock mechanism is inserted into the holes to seal the locking of the sealing cover with the base.
[0035] The sealing cover has holes to permit the access to the Light Emitting Diodes (LED) provided in the energy meter. Under normal conditions such as the unused condition, the holes in the sealing cover are not aligned with the LEDs in the energy meter thereby preventing access to the LEDs. The sealing cover is provided with spring loading mechanism at the back side so that the sealing cover is moved along with an optical reading head (ORH) to enable the Infra red (IR) LEDs provided in the ORH to communicate with the LEDs provided and in the energy meter when the ORH is inserted into the sealing cover. The sealing cover falls back to cover the LEDs in the energy meter to prevent the access to the LEDs when the ORH is removed. The sealing cover has T-shaped projection which is pushed by the ORH in the inserted condition so that the sealing cover moves along with the ORH to align the holes with the optical port to make the LEDs of the energy meter to communicate with the IR LEDs of the ORH to transfer the data from the energy meter to ORH. The sealing cover has a sealing projection provided with a hole so that the hole in the sealing projection at the base and the hole in the sealing projection at the sealing cover are

aligned to receive a sealing wire with a locking mechanism. The sealing wire with the locking mechanism are passed through the holes in the sealing projections in the base and the sealing cover to seal the locking of the seal cover with the base in the assembly, after mounting the sealing cover on the base.
[0036] The metallic washer has holes formed in the periphery to receive the projections provided in the base for hot sealing the mild steel metallic washer with the base in the sealing assembly. The projections in the base are inserted into the holes at the metallic washer and deformed by using a heat treatment process. The metallic washer is provided with a slot which is aligned with the holes in the sealing cover to permit access to the LEDs in the energy meter, when the ORH is inserted. In the unused condition, the slot is not aligned with the holes in the sealing cover. The metallic washer has a cut recess at the periphery to receive and facilitate the movement of the T-projection formed in the sealing cover so that the sealing cover is moved to align the holes in the sealing cover with the slot in the metallic washer to permit the access to the LEDs in the energy meter, when the ORH is inserted. The metallic washer is formed in such a manner that the metallic washer will be physically damaged during the tampering of the sealing assembly and the metallic washer can not be replaced without damage during the replacement.
[0037] Thus the sealing system of the present invention provides a permanently fixed sealing feature on the meter which cannot be restored upon tampering without any physical damage. Under the unused conditions, the optical port is kept closed due to the spring loaded sealing cover thereby preventing the accidental or unauthorized access to the optical port. Even when an unauthorized person tries to remove the

washer, it cannot be put back without any physical damage thereby leaving a physical evidence of the tampering.
[0038] FIG. 1 illustrates an exploded perspective view of an optical port sealing system for an energy meter. The optical port sealing system has a sealing cover assembly provided on the top cover 1 of the energy meter. The sealing assembly is placed on top casing 1 of the energy meter. The sealing assembly has base 2 formed integrally with top cover 1 of the energy meter. Sealing base 2 has recess to receive sealing cover 3 with spring mechanism 7 and metallic washer 4. Metallic washer 4 is provided with holes 9 and slot 6. Base 2 has protrusions 12 that are inserted into holes 9 of metallic washer 4. Sealing base 2 includes rectangular slot 11 to receive spring mechanism 7 provided at the back of the sealing cover 3. Sealing cover 3 is fastened to base 2 with a sealing wire having a locking mechanism. Metallic washer 4 is hot welded to sealing base 2. Base 2 also has sealing projection 13 for sealing of sealing cover 3 using a sealing wire. Sealing projection 13 has a hole which is aligned with the sealing hole provided in sealing cover 3 and a sealing wire with a lock mechanism is inserted into the holes to seal the locking of sealing cover 3 with base 2.
[0039] Sealing cover 3 includes a plastic sealing component with spring mechanism 7 at the back. Two circular holes 5 are formed on sealing cover 3 to permit access to the optical ports, T-shaped projection 8 is formed at one end of sealing cover 3 such that when ORH (9 as shown in FIG. 5) is inserted into slot 6 on metallic washer 4, sealing cover 3 formed below metallic washer 4 is moved along with the ORH to align holes 5 on sealing cover 3 with the optical port in the energy meter to make the LEDs in the energy meter to communicate with the IR LEDs in the ORH to transfer the data from

the energy meter to the ORH. After the removal of the ORH from the optical port, sealing cover 3 retracts to close the optical port due to spring mechanism 7 thereby preventing accidental access during the unused condition. Sealing cover 3 has a sealing projection provided with a hole so that the hole in sealing projection 13 at base 2 and the hole in the sealing projection at sealing cover 3 are aligned to receive a sealing wire with a locking mechanism. The sealing wire with the locking mechanism are passed through the holes in the sealing projections in base 2 and in sealing cover 3 to seal the locking of seal cover 3 with base 2 in the assembly, after mounting sealing cover 3 on base 2.
[0040] Metallic washer 4 is hot sealed to base 2 in the sealing assembly to cover the optical ports in the energy meter and holes 5 formed on sealing cover 3 to prevent the unauthorized access to holes 5. Mild steel washer 4 has three holes 9 formed at the periphery for receiving three vertical projections 12 provided on sealing base 2. Metallic washer 4 is hot sealed to sealing base 2 after providing sealing cover 3 on the base and inserting projections 12 in sealing base 2 into holes 9 of metallic washer 4. Projections 12 in base 2 are inserted into holes 9 at metallic washer 4 and deformed by using a heat treatment process. Metallic washer 4 is provided with slot 6 which is aligned with holes 5 in sealing cover 3 to permit access to the LEDs in the energy meter, when the ORH is inserted. In the unused condition, slot 6 is not aligned with holes 5 in the sealing cover 3. Metallic washer 4 has a recess to receive T shaped projection 8 in sealing cover 3 so that sealing cover 3 be moved down or upwardly to prevent or permit the alignment of holes 5 in sealing cover 3 with slot 6 in metallic washer 4. Metallic washer 4 is formed in such a manner that metallic washer 4 will be

physically damaged during the tampering of the sealing assembly and the metallic washer can not be replaced without any damage during the replacement.
[0041] FIG. 2 shows the exploded and the assembled view of the sealing cover in the optical port sealing system according to one embodiment of the present invention. Sealing cover 3 includes a plastic sealing component with spring mechanism 7 at the back. Two circular holes 5 are formed on sealing cover 3 to permit access to the optical ports. T-shaped projection 8 is formed at one end of sealing cover 3 such that when an ORH (as shown in FIG.5) is inserted into the slot on the metallic washer, sealing cover 3 formed below the metallic washer is moved along with the ORH to align holes 5 on sealing cover 3 with the optical port in the energy meter to make the LEDs in the energy meter to communicate with the IR LEDs in the ORH to transfer the data from the energy meter to the ORH. After the removal of the ORH from the optical port, sealing cover 3 retracts to close the optical port due to spring mechanism 7 thereby preventing accidental access during the unused condition. The sealing cover -has a sealing projection provided with a hole so that the hole in the sealing projection at the base and the hole in the sealing projection at the sealing cover are aligned to receive a sealing wire with a locking mechanism. The sealing wire with the locking mechanism are passed through the holes in the sealing projections in the base and the sealing cover to seal the locking of the seal cover with the base in the assembly, after mounting the sealing cover on the base.
[0042] FIG. 3 illustrates an exploded view and the assembled view of the sealing cover and the top case in an optical port sealing system according to one embodiment of the present invention. Sealing base 2 is formed integrally with top cover 1 of the

n
energy meter. Sealing base 2 has recess to receive sealing cover 3 with spring mechanism 7 and a metallic washer provided with holes. Base 2 has protrusions 12 that are inserted into the holes of metallic washer 4. Sealing base 2 includes rectangular slot 11 to receive spring mechanism 7 provided at the back of sealing cover 3. Sealing cover 3 and metallic washer 4 are hot welded to sealing base 2. Sealing cover 3 has two circular holes 5 to permit access to the optical ports in the energy meter. T-shaped projection 8 is formed at one end of sealing cover 3 such that when the ORH is inserted into the slot on the metallic washer, sealing cover 3 is moved along with the ORH to align holes 5 on sealing cover 3 with the optical port in the energy meter to make the LEDs in the energy meter to communicate with the IR LEDs in the ORH to transfer the data from the energy meter to the ORH. The sealing cover has a sealing projection provided with a hole so that the hole in the sealing projection at the base and the hole in the sealing projection at the sealing cover are aligned to receive a sealing wire with a locking mechanism. The sealing wire with the locking mechanism are passed through the holes in the sealing projections in the base and the sealing cover to seal the locking of the seal cover with the base in the assembly, after mounting the sealing cover on the base.
[0043] FIG. 4a illustrates an exploded view of the mild steel washer 4 and the top case with sealing cover assembly in the optical port sealing system for energy meter according to one embodiment of the present invention, while FIG. 4b illustrates the assembled and enlarged views of mild steel washer 4 and the top case with sealing cover assembly in the optical port sealing system for energy meter according to one embodiment of the present invention. With respect to FIG. 4a and FIG. 4b, mild steel washer 4 is mounted and hot sealed with the top cover of the energy meter after

installing sealing cover 5 on the base. Three circular holes 9 are provided on mild steel washer 4 along its outer radius to receive vertical projections 12 formed on the base of sealing cover assembly to hot seal mild steel washer 4 with the base in the sealing assembly. Projections 12 in the base are inserted into holes 9 at mild steel washer 4 and deformed by using a heat treatment process. Recess 10 is provided at the periphery of metallic washer 4 to receive and facilitate the movement of T-shaped projection 8 provided at the sealing cover. Rectangular slot 6 is provided on metallic washer 4 to provide an access to circular holes 5 on sealing cover 3 whenever the ORH is inserted. FIG. 4b shows an assembled view of mild steel washer 4 and top case in sealing cover assembly before and after a hot sealing operation.
[0044] FIG. 5 a and FIG. 5 c illustrate the perspective and enlarged top plan views of an optical port sealing system for energy meter according to one embodiment of the present invention respectively before the insertion and after the removal of the optical reading head assembly, while FIG. 5b illustrates the perspective and enlarged front plan views of an optical port sealing system for energy meter according to one embodiment of the present invention with the inserted condition of the optical reading head assembly. With respect to FIG. 5a, ORH 9 is not inserted into slot 6 in metallic washer 4 of the optical port sealing assembly. Slot 6 in metallic washer 4 covers the holes in the sealing cover arranged below the metallic washer, before the insertion of ORH 9 into the optical port. Slot 6 in metallic washer 4 is not aligned with the holes in the sealing cover thereby preventing the access to the LEDs in the energy meter.
[0045] With respect to the FIG. 5b, ORH 9 is inserted into slot in metallic washer 4 of the optical port sealing assembly so that T-shaped projection 8 in the sealing cover is

moved by ORH 9 thereby moving the sealing cover along with ORH 9. Slot 6 in metallic washer 4 aligns with the holes in the sealing cover arranged below metallic washer 4 and the holes in the sealing cover is aligned with the optical port to make LEDs 14 in the energy meter to communicate with the IR LEDs in ORH 9 to transfer the data from the energy meter to ORH 9.
[0046] With respect to FIG. 5c, ORH 9 is removed from the optical port sealing assembly after performing a reading operation. The sealing cover falls back to its original position due to the spring mechanism in the sealing cover thereby preventing access to the optical port in the energy meter. As a result, the slot in the metallic washer covers the holes in the sealing cover arranged below the metallic washer, after the removal of the optical reading head. In unused condition, the holes on the sealing cover provided for accessing IR LEDs remain unaligned from the meter LEDs, thus preventing access to the optical ports.
[0047] The sealing assembly in the present invention provides a unique arrangement for protection of the optical ports in the energy meter. It provides a permanently fixed sealing feature on meter, which cannot be restored upon tampering. It provides a simple, tamper proof sealing assembly. In unused condition the sealing cover retracts to its original position due to the spring mechanism and the holes in the sealing cover is not aligned with the optical ports in the energy meter thereby preventing any accidental access to the optical port. The sealing assembly includes the metallic washer which can not be replaced without any physical damage thereby providing a physical evidence of the tamper event.

G) ADVANTAGES OF THE INVENTION
[0048] The various embodiments of the present invention provide an optical port sealing system for energy meters. The system provides a unique permanently fixed sealing feature on the energy meter, which cannot be restored upon tampering without any physical damage. It provides a simple, tamper proof sealing assembly. In unused condition, the sealing cover retracts to its original position due to the spring mechanism and the holes in the sealing cover are not aligned with the optical ports in the energy meter thereby preventing any accidental access to the optical port. The sealing assembly includes the metallic washer which can not be replaced without any physical damage thereby providing a physical evidence of the tamper event.
[0049] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.
[0050] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said

CLAIMS
What is claimed is:
1. An optical port sealing system for energy meter comprising:
a sealing base formed integrally with the top cover of the energy meter;
a sealing cover provided with holes and T-shaped projection mounted on the
sealing base;
a spring mechanism provided at the back of the sealing cover; and
a washer with a slot provided on the sealing cover and hot sealed to the sealing
base;
wherein the sealing cover is moved by the insertion of an optical reading head
to align the holes in the sealing cover with the optical port in the energy meter
to read stored data from the energy meter.
2. The system according to claim 1, wherein sealing cover is moved back by the spring mechanism to close the optical ports to prevent the accidental access to the optical port, when the optical reading head is removed from the energy meter.
3. The system according to claim 1, wherein the T-shaped projection in the sealing cover is displaced by the insertion of the optical reading head to enable the sealing cover to move along with the optical reading head to align the holes in the sealing cover with the optical port in the energy meter to read the stored data in the energy meter.

4. The system according to claim 1, wherein the sealing base has vertical projections to hot seal the base with the washer.
5. The system according to claim 1, wherein sealing base has a first sealing projection provided with a hole to seal the sealing cover with the base after the mounting of the sealing cover on the base.
6. The system according to claim 1, wherein the sealing base has a slot to receive the spring provided at the back of the sealing cover.
7. The system according to claim 1, wherein the sealing cover has a second sealing projection with a hole to align with the hole in the first sealing projection provided in the sealing base to receive a sealing wire with a locking mechanism to seal the locking of the sealing cover with the sealing base.
8. The system according to claim 1, wherein the washer has holes provided along the periphery to receive the vertical projections to hot seal the washer with the sealing base.
9. The system according to claim 1, wherein the vertical projections in the sealing base are inserted into the holes at the periphery of the washer and deformed by applying a heat treatment process to hot seal the washer with the sealing base.

10. The system according to claim 1, wherein the washer has a recess to receive
the T-shaped projection provided in the sealing cover to enable the movement
of the T-shaped projection during the insertion of the optical reading head.
11. The system according to claim 1, wherein the washer is a metallic washer.
12. The system according to claim 1, wherein the metallic washer is a mild steel
washer.