INTRODUCTION ;
The present invention relates to an externally controlled robot car assembly for internal inspection of pulverized coal feed pipe. More particularly, this invention pertains to inspection of internal condition by Robot Car Assembly in coal based thermal power plants wherein coal is introduced in the boiler in pulverized form, conveyed from the pulverizer to the boiler with the help of pressurised air (primary air). Air carrying the pulverized coal particles through pipes between the pulverizer and boiler which often have several bends. In those bends coal stream suddenly changes direction exerting considerable outward force on the outer wall of the pipe. This force increases the erosion of the pipe inner surface at the bent part of the particular walls. In order to protect those portions of pipes under stress, a layer of ceramic tiles are provided in those bends. These particular ceramic tiles are not eroded by the coal stream and protect the pipe from getting damaged. However, with continuous operation such ceramic tiles are prone to get dislodged from their position. Once one of the tiles gets dislodged, the air gets obstructed in that gap and creates a vortex around it creating considerable force on the nearby tiles ; as a result thereof it initiates an avalanche of failure and dislodging of tiles, whereby with removal of ceramic layer the pipe metal surface gets exposed in the outer bend, which eventually gets eroded and coal leakage takes place from the outer wall of the pipe. To replenish the ceramic protective layer one has to undertake a forced shut down of the system resulting in a loss of availability of the unit at the grid, which has a negative impact on the grid stability as well as results in considerable commercial loss to the organization.
To keep a tab on such an eventuality periodic inspection of the bends is necessary. A practical operational difficulty may be enumerated as under :
a) Manual Inspection : The coal pipe internal diameter is usually around 630 mm; hence any possibility of a physical inspection is hardly possible as it is impractical for a human to enter the pipe and inspect.

b) Boroscope : A normal horoscope can go up to 15m inside the pipe whereas the coal pipe often extends to length of 60M or more and thus a normal boroscope is unable to carryout inspection of the interior condition of the entire coal pipe length.
c) Dismantling of Pipes :Inspection of all pipes interior by dismantling will necessitate a huge investment in terms of money, manpower and loss of production.
To overcome the drawbacks and difficulties envisaged by the industry, a robotic car assembly has been designed which substitutes human, ocular inspection inside the pipe by means of IR/HD cameras mounted on a robot car assembly capable of moving inside the coal pipeline with the help of a joy stick, remotely operated from outside. As the whole pipeline runs horizontal after the first vertical drop at the burner end, vertical movement of the robot car was avoided. The robot car can move forward/backward to navigate inside the pipe. It can also rotate about its axis thereby enabling it to easily manoeuvre through the horizontal bends inside the pipelines. The wheels of the robotic car were so designed that the entire assembly could easily negotiate the bellows inside the pipes without shifting the center of gravity of the car to high making it unstable.
The primary objective of this invention is to provide an externally controlled robot car assembly for internal inspection of pulverized coal feed pipe leading from pulverizer to the boiler.
A further object of this invention is to provide an externally controlled robot car capable of moving backward/forward over bellows inside the pipes with the

help of wheels capable of negotiating the different types of terrain inside the coal pipe.
A still further object of this invention is to provide a robot car which can execute both translational and rotary movements inside the coal pipe for the purpose of inspection.
Yet another object of this invention is to provide a plurality of IR/HD cameras chosen as payloads which will transmit continuous visuals of pipe internals when connected to a laptop or a similar portable device wherein one can watch the live visuals and can move the car inside the pipeline accordingly.
Still another object of this invention is to provide a robot car with three cameras mounted on top, rear and front of the robot car acting as one single unit of inspection and projecting the inside condition in the form of visual which can be seen analyzed and archived from the laptop screen.
Another object of this invention is to provide an externally controlled robot car incorporating through external supports like power supply, remote control of movement like forward, backward, translational and rotatory and videofeed from the car which should be live streamed outside without any delay so that the car may be operated inside the pipeline without any hindrance.
The foregoing objectives are attained by the present invention which relates to an externally controlled robot car assembly for internal inspection of pulverized coal feed pipe leading from pulverizer to the boiler, characterized in that said robot car comprising in combination the following constituent components like a chassis having main carriage mounted on wheels capable of moving backwards/forward and over bellows inside the pipe, equipped with a plurality of cameras mounted on top front and rear positions of the said robot car,

connected to a portable controlling unit through Switched Mode Power Supply and network switch which in turn carries a charging port and an on/off switch.
The portable controlled unit used in the invention may optimally be a laptop.
The main power for the locomotion of the robot car is supplied by 5000 mAh rechargeable battery mounted on the car itself which can be charged by 240 Volt AC supply. Additional power source of similar capacity is needed for communication and cameras, which is supplied from the operating station outside the coal pipe by means of a copper cable.
Three external supports are provided for operation of the car within the confined space of the coal pipe e.g. :
i) Power Source :The car is fed with external 240VAC power supply to power the cameras and the networking switches mounted on the car by means of a cable connected to the robot;
ii) Remote Control of Movement :Control signal/(s) needs to be issued from a joystick placed at the control station through a suitable Ethernet cable attached to the robot car.
iii)Video Feed :Video feed from the robot car while in operation should be live streamed for unhindered propagation of the car inside the confined space of the pipeline. The same video feed is used for analysis and archival. The same is communicated from the car to control station by an Ethernet cable.
All the three aforesaid cables (i), (ii) and (iii) are twisted and made into a single one for ease of handling the car.

While selecting the material of construction of the main body of the car, choice was made keeping weight of the materials in mind, to accommodate many number of pay loads. The drive motor is so chosen as to have variable/torque/speed and the center of gravity of the car is kept low for the purpose of imparting stability to the entire car assembly.
The main body of the car may be fabricated from light weight, inert, impact resistant material such as HDPE (High Density Polyethylene), Nylon, Acetal, Polycarbonate-HDPP (High Density Polypropylene).
It has optimally been found that energy consumption is 60 Watts and the car can operate for 4 hours after single charging. The distance traversed by the car is up to 45m inside the pipeline. As mentioned earlier the motor is capable of executing both translational and rotational.
The invention will now be further illustrated by means of the drawing accompanying the specification wherein Figure 1 gives a side view of the vehicle, Figure 2 shows the front view of the vehicle and Figure 3 gives a top view of the vehicle locating the different constituent parts.
In Figure 1 : (1) stands for main carriage of the car, (2) shows the wheels, (3) shows the location of Switched Mode Power Supply and Network switches (4) is the top camera (5) locates charging port, (6) stands for on/off switch.
In Figure 2 :Numerals 1 to 4 have the same significance as in Figure 1, and (7) denotes the location of front camera.

Turning next to Figure 3 : Giving a top view of the vehicle and indicate locations of top, front and rear cameras the last named showing the location of rear camera.
From the arrangement as depicted in the top view of the vehicle, the three cameras 4, 7 and 8 play an important role in video graphing and transmitting the images to a portable instrument like laptop which helps the persons in charge of operating the robotic car. The same will determine the health of the coal pipe particularly at the bends. It also helps to decide whether replacement of ceramic tiles is needed or not which in turn would avoid the necessity of a shutdown.
A typical robotic car assembly used in this invention may have the following dimensional details:
a) Wheel Dia - 110 mm
b) Distance between the Front and Rear Wheels : 90 mm. Upper surface of top camera - 65 mm.
In Figure 2 : Width of the wheel 26 mm,
Width of the Vehicle :210 mm Base of the Top Camera - 105 mm Width of the entire Assembly : 300 mm Top Surface Area of Front Camera - 65 mm
Turning next to Figure 3 :The actual measurement of the chassis of the robot car 200 mm between the wheel to wheel, length of the chassis 270 mm and width of the chassis 210 mm.

Switched Mode Power Supply and network switch using 128 mm
X 76 mm, Exterior top surface of front camera - 65 mm, base - 105 mm.
The advantages of the subject invention can be briefly stated as follows:
(i) Almost all the bends can be closely checked during every overhauling without dismantling a single pipe. Health of ceramic tiles can also be checked externally, unless those pipes which are damaged in the course of operation need to be dismantled and replaced without affecting operation of the plant.
(ii) Any problem related to coal pipe internals is possible to be diagnosed even at an initial stage which helps to prevent any unforeseen and sudden leakage due to pipe failure and resultant loss of production.
(iii) The robot car is capable of inspecting the coal deposition in the pipe internal walls which goes a long way to issue an early warning before any clogging in coal pipes sets in.
(iv) This robot car can be effectively used for inspection of any leakage of hazardous chemicals flowing through a pipeline from a safe distance.
(v) Similar car assembly can effectively be used in any other pipe having a diameter exceeding 400 mm such as, for instance, to inspect CEP suction line from hot well.

Although the preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate the various modifications, additions and substitutions are possible without deviating or departing from the scope and spirit of the invention as recited in the claims appended hereafter :

We claim :
1. An externally controlled robot car assembly for internal inspection of
pulverized coal feed pipe leading from pulverizer to the boiler, characterized in
that said robot car comprises, in combination, the following constituent
components like a chassis having main carriage (1) mounted on wheels (2)
capable of moving backwards/forward and over bellows inside the pipe,
equipped with a plurality of cameras mounted on top (4), front (7) and rear
positions (8) of the said robot car, connected to a portable controlling unit
through Switched Mode Power Supply and network switch (3) which in turn
carries a charging port (5) and an on/off switch (6).
2. A robot car as claimed in Claim 1, wherein the portable controlling unit is
a laptop.
3. A robot car as claimed in Claims 1 and 2, wherein main power for the
locomotion of the robot car is supplied by a 5000 mAh rechargeable battery
mounted on the car itself which can be charged by 240 VAC supply and an
additional power source of 240 VAC needed for communication and cameras
supplied from the operating station outside the feed pipe by means of a copper
cable attached to the car.
4. A robot car as claimed in Claims 1 to 3, wherein there is provided three external supports for operation of the said car within the confined space of the coal feed pipe, such as, for instance :-

(i) power source - the car is fed with 240 VAC power supply from outside to
power the cameras and network switches mounted on the car by means of a cable connected to the robot;
(ii) remote control of movement - control signal/(s) needs to be issued from
exterior source through a suitable 'Ethernet' cable attached to the robot car, and
(iii) video feed - video feed from the robot car while in operation should be externally live streamed for unhindered propagation of the car inside the pipeline which is ensured by another cable connected to the car and aforesaid three cables (i), (ii) and (iii) are twisted and made into a single one for ease of handling the car.
5. A robot car as claimed in Claims 1 to 5, wherein the material of
construction of the main body of the car was chosen from lightweight components to accommodate more number of payloads and the drive motor is so chosen as to have variable torque/speed and the CG of the car is kept low for the purpose of imparting stability to the entire our assembly.
6. A robot car as claimed in any of the preceding claims, wherein the main car body is fabricated from lightweight, inert, impact resistant material such as HDPE (high density polyethylene), nylon, acetal, polycarbonate and HDPP (high density polypropylene).
i

7. A robot car as claimed in any of the preceding claims, in which power spent in operating the system is 60 watts and the distance traversed by the car is upto 45 meters inside the feed pipe and the motor is capable of executing both translational and rotational movements within the confined space of the coal feed pipe.