COAXIAL AUTO-RETRACT FURNACE VIDEO CAMARA

Transcription

1 COAXIAL AUTO-RETRACT FURNACE CATALOGO VC-XT

2 Spherical pivoting The ability to observe various zones within a boiler furnace, is sometimes very important. This system includes an spherical pivoting wall support wich provides this feature. One person can adjust the orientation of the lens frontal tip, and fix it into position very easily.

3 Spherical pivoting The drawing below shows a lateral cross sectional view of the retract system introduced into the furnace wall 2 through the spherical wall support 4. The support pipe 3, passes through the sphere until it reaches the centerline of the furnace wall tubes 1. A set screw, not shown, fixes this position, so as to protect the lens tube 6 when it is inserted into the furnace. Photo 1 shows the wheel handle used to tighten the sphere into position. Photo 2 shows the sphere inside the spherical wall support 4. The spherical wall support includes one threaded connection 7,which allows for external cooling air to be injected at low pressures (5 to 10 WC).

4 A extremely simple control box is required, since it fails in the retracted position, using only the spring power. There is no need for additional instrumentation beyond the following. 1 Air filter regulator, ensures clean high capacity air flow to the rear end of the housing. This air cools the camara and lens tube, as well as providing the pistons thrust required to move the piston and lens tube forward into the furnace. 2 Solenoid Valve, normally closed, is opened by the Temperature Controller 4. 3 DC Power Supply, recevies 110 VAC and feeds DC Power to the controller. The Coaxial Auto-Retract System responds to the following events: Loss of energy supply. Thermocouple circuit open. Over-temperature. Loss of air supply. The temperature controller has a main contact which is closed when the measured temperature is greater than the Set Value (normally 100 C). COAXIAL AUTO-RETRACT FURNACE The control box CONTROL BOX OPERATION Additionally the controller is provided with another contact (AL1) that is switched to close only when temperature sensor circuit is open. Using these two contacts in parallel, we control the solenoid valve. At any time when one or both contacts change or energy from power supply fails, the solenoid valve will be closed, thereby cutting air supply which in turn causes the piston and lens tube to retract. The same response occurs when air supply is lost.

5 Air and power connections 1 Electrical Conduit, protects the cables that run from the control box to the camara inside the housing. One cable supplies12vdc, a second cable brings the video signal from the camara to the control box, the third one is a thermocouple cable that connects directly to the temperature controller. 2 Compressed Air House, delivers clean compressed air at 10 to 20 PSI to the chamber behind the piston. This air also provides cooling air for the camara and the lens tube.

6 Removing the rear cover By removing the rear cover we obtain access to all the internal components of the coaxial auto-retract furnace video camara. The rear cover receives the compressed air hose and cable conduit with two cable connectors wich allow for easy removal of the cover, leaving the coiled cable attached to the piston assembly. This feature is very important since it allows very simple and quick access to the camara even with the boiler in operation.

7 RETRACTIL PARA INSPECCION DE CALDERA Removing the piston, lens tube and spring After removing the rear cover and disconnecting the cables, the piston assembly with the coiled cables are ready to be extracted. It is as easy as holding the piston, while it is pushed out by the spring. We can now inspect the front lens element, the cooling jacket, the spring, the piston s seal and the coiled cables. This assembly can now be taken to an inspection table at the instrumentation lab. The time that it takes to do this operation is less than one minute. The open end of the housing 2A, see photo 2, DOES NOT see any flue gases since the check valve at the front plate blocks this gases from entering the housing.

8 RETRACTIL PARA INSPECCION DE CALDERA Removing the camara from the piston The piston has a back cover plate held by 4 allen head screws that are easily removed as shown in picture 1. Once the back cover plate is removed, the camara enclosure 2A is exposed. Looking into the front end we see a filter lens 4A, a power and video cable 2A and a thermocouple connector 3A. These cables are connected to the coiled cable, through connectors attached to the back cover plate 3A 5A.

9 Accessing the CCD board The CCD board is selected according to the requirements of the application, and it is rarely changed, because it is protected by the enclosure and continuously refrigerated. The standard CCD board has the basic specifications in the table below. This is the heart of the system, the image sensor 1 and the electronics convert the image provided by the lens tube into an analog video signal that can be directly sent to a monitor.

10 Accessing the lens tube In order to acces the lens tube, the cooling jacket 1A, has to be removed by loosening 4 screws and sliding the cooling jacket over the lens tube 4A. Figure 4 shows a detail view of the lens tube front tip, where the thermocouple is attached in order to sense the temperature nearest the front lens. It is very important that this thermocouple is in good condition, since the life of the lens tube depends on sensing this temperature continuously. The annular space between the lens tube and the cooling jacket, will carrie the cooling air flow, thereby protecting the lens tube from overheating. The lens tube is the most expensive component of the system and the most delicate, since it can be damaged by heat, moisture, oils, or particulate entering the lens tube.

11 Disconnecting hose and cables To disconnect the cables and hose from the control box is as simple as following these steps: 1. In photos 1 and 2, 2 we see the quick disconnect coupling installed on the back cover. Remove the hose by pulling this coupling. 2. Disconnect cables in the control box, see photo Detach the conduit from the control box. Now the hose remains connected to the control box and the cable s conduit remains attached to the back cover of the retract assembly.

12 Inspecting the check valve In order to inspect the check valve, the housing, with the wall support adapter and the support pipe need to be removed from the spherical wall support see photo 11. Remove the wall support adapter and support pipe by loosening 4 screws that atached it to the front plate of the housing Photo 4. 4 shows the check valve disc and the valve seat.

13 Connecting camara cables to control box