METHOD OF MONITORING ACCESS COVERS OF UNDERGROUND INFRASTRUCTURE PARTICULARLY OF CAST IRON OR CAST IRON-CONCRETE COVERS AND A COVER MADE ACCORDING TO SAID METHOD

Abstract

An access cover to underground city infrastructure, particularly a cast iron or a cast iron-concrete cover provided with a cover detection sensor connected with a radio frequency signal transmitting antenna through a transmitter, characterised in that an antenna module (1) provided with a housing made of a material neutral to electromagnetic fields, preferably made of plastic, is installed in the through channel (4) with variable cross-section, and removably fixed at the bottom to a sensor module (2) located underneath the bottom of the cover (3), provided with a battery powered, low current electronic system containing a radio transmitter and an acceleration sensor or a gyroscope and an appropriate controller which detects changes to the position of cover (3) in space and in time, whereby the surface area of the sensor module (2) is greater than the surface area of the through channel (4). The object of the invention also includes a method of cover monitoring.

Claims

1-4. (canceled)

5. An access cover for accessing underground city infrastructure, comprising: a cover formed from cast iron or cast iron concrete and having top and bottom surfaces; a channel having a variable cross-section and formed within the cover; a sensor module having a largest cross section greater than a smallest cross-section of the channel and disposed adjacent the cover bottom surface and having a low current, battery powered electronic system including a radio transmitter, a controller, and a sensor formed from an acceleration sensor or a gyroscope, for detecting temporal and spatial changes to cover position; and an antenna module disposed in an antenna housing formed from electromagnetic-neutral material and disposed within the channel and removably affixed to the sensor module for receiving radio frequency signal via the sensor module transmitter.

6. The cover of claim 5, wherein the sensor is disposed in a compartment formed in the channel.

7. The cover of claim 5, wherein the sensor is disposed underneath the cover bottom surface.

8. The cover of claim 5, wherein a top surface of the antenna housing facing the cover top surface comprises a top layer of material resistant to chemical, thermal, and mechanical influences.

9. The cover of claim 8, wherein resistant material comprises high temperature resistant non-metallic material.

10. The cover of claim 5, wherein the antenna module is removably affixed to the sensor module by screws or clip-type connections.

11. A method for monitoring access covers for accessing underground city infrastructure, comprising: providing an access cover for accessing underground city infrastructure, comprising: a cover formed from cast iron or cast iron concrete and having top and bottom surfaces; a channel having a variable cross-section and formed within the cover; a sensor module having a largest cross section greater than a smallest cross-section of the channel and disposed adjacent the cover bottom surface and having a low current, battery powered electronic system including a radio transmitter, a controller, and a sensor formed from an acceleration sensor or a gyroscope, for detecting temporal and spatial changes to cover position; and an antenna module disposed in an antenna housing formed from electromagnetic-neutral material and disposed within the channel and removably affixed to the sensor module for receiving radio frequency signal via the sensor module transmitter. transmitting temporal and spatial changes to position of the cover to a receiver.

12. The method of claim 11, wherein the transmitting of temporal and spatial changes is effectively instantaneous.

Description

EXAMPLE I

[0008] As FIG. 1 shows, cover 3 of a cast iron or a cast iron-concrete manhole is placed on body 5. A small through channel 4 is provided in the central part of cover 3, with an inverted frustoconical cross-section changing to a cylindrical cross-section. Antenna module 1 is placed inside channel 4, with sensor module 2 attached to the antenna module 1 on the bottom side 3 of the cover. The surface area of sensor module 2 is larger than the area of channel 4 cross-section. An antenna enabling communication, i.e. wireless transmission of alarm messages, is provided in the antenna module 1, the housing of which is made of a plastic practically neutral to electromagnetic field. The design of antenna module 1 is resistant to attempts of mechanical damage thanks to its shape, i.e. thanks to its small surface area and lack of practical possibility of pushing it inside or removing it because of its screwed connection with sensor module 2. Hole 4 provided in the cover allows signal to be transmitted by the antenna. A low current, energy-saving electronic system with a battery powered radio transmitter is provided in the sensor module 2. The electronic system includes an acceleration sensor or a gyroscope. An appropriate controller detects cover motions characteristic for cover opening, i.e. changes to the inclination angle or general position changes in space and in time. Duration of analysed phenomena is very important, as sensor module 2, under real operational conditions of the manhole cover, may generally very often detect accelerations and changes to the inclination angle caused by vibrations in the environment, or by stepping or driving over the cover 3, especially if the cover is not installed stably enough. A dedicated algorithm allows systems indicating cover 3 being lifted to be effectively identified among many signals transmitted by the sensor module 2. Sensor module 2 uses energy saving electronic components, in particular the radio transmitter, which allows many years of uninterrupted operation of the entire system using a battery as a power source, without the need to replace the battery.

EXAMPLE II

[0009] Cover 3 is made as in Example I, with the exception that the top housing part of the antenna module 1 is covered with a composite material with high resistance to stretching, of kevlar type, or of a non-metallic material resistant to high temperatures.

EXAMPLE III

[0010] As FIG. 2 shows, cover 3 is made as in Example I, with the exception that sensor module 2 is installed inside cover 3, in a compartment 6 formed in the bottom part of the through channel 4.

EXAMPLE IV

[0011] Sensor module 2 allows detection and processing of changes of position of the cover 3 executed as in Example I, in Example II or in Example I in space and in time, subsequently antenna provided in the antenna module 1 wirelessly sends a signal characteristic for opening of cover 3 to a receiver of the cover owner.