US 3609236 A
Description (OCR text may contain errors)
United States Patent  lnventor Wesley H. l-Ieilman Baltimore, Md.
Sept. 30, 1968 Sept. 28, 1971 Bethlehem Steel Corporation [21 Appl. No.  Filed  Patented  Assignee [S4] APPARATUS FOR TELEVISING THE INTERIOR 0F HAZARDOUS CHAMBER 8 Claims, 3 Drawing Figs.
 US. Cl 178/7.92, l78/D1G. 1,178/DlG. 14, 340/229, 350/79, 350/84, 350/253 [51} Int. Cl 1101] 29/89  Field of Search l78/7.92,
DIG. l, DIG. 14; 356/44, 49; 350/79, 84,187, 247, 253, 255; 340/227, 229, 236, 239, 240, 242
 References Cited UNITED STATES PATENTS 2,672,798 3/1954 Snyder 178/792 3,021,386 2/1962 Clark .4 l78/DIG. 1
3,075,113 1/1963 Soar.... l78/DIG.1
3,277,238 10/1966 Sharp 178/D1G. 1
3,229,577 l/l966 Ellinger 350/79 FOREIGN PATENTS 1,141,529 12/1962 Germany 178/D1G. 14
Primary Examiner-Robert L. Griffin Assistant ExaminerJoseph A. Orsino, J r. Attorney-Joseph J. O'Keefe ABSTRACT: A cooled and purged television camera and lens assembly is mounted on a powered operator adjacent an apertured hazardous chamber. The powered operator is adapted to extend and retract the lens into and out of the aperture. Control means acts on the operator to cause automatic retraction of the lens upon loss of the cooling and purging media. Provisions are made for limiting lens movement by the powered operator.
APPARATUS FOR TELEVISING THE INTERIOR OF HAZARDOUS CHAMBER BACKGROUND OF THE INVENTION This invention relates broadly to closed circuit television systems. More specifically, it relates to apparatus for televising the interior of hazardous chambers, viz., high-temperature furnaces, boilers and the like, such as are used in heavy industries.
Closed circuit television systems are used in the steelmaking industry, for example, to televise the interior of billet reheating furnaces. In such installations, a mill operator uses remotely controlled apparatus to continuously charge cold billets into the furnace, manipulate the billets along a furnace hearth, and discharge them when heated to their plastic state at about 2250 F. It is therefore essential that the operator be informed of billet heat and alignment conditions at all times. Continuous human observation of these conditions is not only impractical but actually hazardous because of the flow of high-temperature gases, mill dust, etc., in and around the furnace. Hence, a closed circuit television system is provided for these observations.
In such installations, prior art television apparatus generally consisted of a television camera and extension lens assembly which is secured directly to the furnace wall, frequently by means of a rigid support member, whereby the lens is fixedly positioned in a viewing aperture or port. The camera and lens are provided with cooling and purging means, since the furnace environment greatly exceeds the temperature and mechanical ratings of the electro-optical components. Of times a fluid-cooled viewing port is required which also serves as a base for mechanically coupling the camera and lens assembly directly thereto.
Under the foregoing conditions, significant amounts of heat and vibrations are transmitted through the viewing port and supporting structures which may have adverse affects on the television camera and extension lens. Further, heat conduction from the furnace through the support member places an added burden on the cooling means. Moreover, maintenance, inspection and replacement times of the television camera and lens assembly are high because of complicated dismantling and assembling procedures involved in some of the support structures. More important, however, is the fact that when experiencing a reduction, or loss, of the cooling and purging effects, irreparable damage occurs to the extension lens and generally the television camera as well. This may prove costly not only in terms of replacements but also in downtime of the billet reheating furnace and associated production facilities.
SUMMARY OF THE INVENTION One of the objects of this invention is to provide improved apparatus for televising the interior of chambers having heat or particle hazardous operating conditions.
Another object of this invention is to provide said apparatus with cooled or purged components whose total supply requirements are less than prior art devices.
Still another object of this invention is to provide the cooled or purged apparatus with means for preventing component damage from operating hazards due to reduction, or loss, of the cooling or purging effects.
A further object of this invention is to provide the aforesaid apparatus with facilities to minimize maintenance, inspection and replacement downtime.
The foregoing objects can be attained by assembling a television camera and extension lens in protective housings and providing a cooler which utilizes compressed air for cooling or purging these devices, by mounting the housed camera and lens assembly on a powered operator which is adapted to extend and retract the lens into and out of an aperture in the furnace wall, and by controlling movement of the operator with means which acts on the operator to retract the lens due to a reduction, or loss, in compressed air pressure.
DESCRIPTION OF THE DRAWING FIG. 1 is a partial side elevation view combined with a vertical sectional view taken along the longitudinal centerline of one embodiment of the invention.
FIG. 2 is a lateral cross-sectional view taken along line 22 of FIG. 1.
FIG. 3 is a block diagram of the control means associated with the FIG. 1 embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, the television apparatus of this invention is seen located outside of chamber 10 which, for illustrative purposes, is a billet reheating furnace. An aperture 11 is located in chamber wall 12, or other suitable surface, to provide remote viewing of the interior chamber 10. Aperture 11 is large enough to permit free axial movement therein of an extension lens and housing (described below), yet small enough to minimize the amount of hot gases and dust particles that may escape to the atmosphere with the lens in place.
Referring to FIGS. 1 and 2, the housed television camera and extension lens assembly, indicated generally at 13, and the cooling means, indicated generally at 14, are similar in construction to that of Sharp et al. described in U.S. Pat. No. 3,277,238. Assembly 13 comprises a television camera l5 connected through cable l6 to a television monitor (not shown). and an extension lens l7 which is optically coupled to camera 15. Lens 17 is positioned in aperture l l and includes an objective element l8 located at its tip which, for example, provides an angular field of view of about Under these conditions, the televised scene viewed by an observer will include a substantial portion of the interior of chamber 10.
As can best be seen in FIG. 1, television camera 15 and extension lens 17 are enclosed in housings l9 and 20. respectively. These housings are commercially available and are designed to protect devices 16, 17 against the environmental hazards of heat and dust normally found in and around chamber 10. Housing 19 includes support members 21 for mounting camera 15 relative to an optical axis which extends through camera 15 and lens 17. Housing 20 includes solid bushing 22 and perforated bushing 23 which support lens l7 coaxially therein.
Lens housing 20 is fitted with mounting flange 24 which enables extension lens 17 to be mechanically and optically coupled with television camera 15. Flange 24 is structurally integrated with camera housing 19 by rigid plate 25, the latter being held in position by studs 26. Plate 25 also serves as a barrier against hot gases and particles escaping from aperture 1 1.
Cooling means 14 comprises a source of compressed air (not shown) which is fed through conduit 27 at about 80-100 p.s.i., an air filter 28, a pressure regulator 29 where the air pressure is reduced to about 30-60 p.s.i. and registered on gage 30, and cooler 31 which is mounted on camera housing 19 and operated from compressed air fed from regulator 29.
Cooler 31 consists of a simple, commercially available. Ranque tube device. Sharp et al. characterize the Ranque tube as a vortex tube type of cooling unit which, when supplied solely with air under pressure at a given temperature will operate to transform the inlet air into two outlet streams, one cooler and the other warmer than the inlet air.
By way of example, a given size Ranque tube when supplied with about 30-40 cfm. of F. air at about 60 p.s.i. at inlet conduit 32, will transform about l2% of the inlet air to a 30 F. cool output flow through conduit 33 and the remainder to a l40-l45F. warm output flow through conduit 34. Thus, with a relatively small volume and pressure input a temperature differential of about l00 F. may be obtained. It should be noted. however, that this unit will operate at inlet air pressures as low as 30 p.s.i. but that only about an 80 F. temperature differential will be obtained.
The flow of cool air through conduit 33 is directed into camera housing 19 and around television camera 15. Here the cool air picks up heat emitted by these sources and is then discharged through orifice 35 to the atmosphere. The amount of heat gained by the air is predetermined to maintain the electro-optical components in housing 19 within their normal temperature ratings. This is done by sizing orifice 35 in relation to the air pressure established by regulator 29 to affect a predetermined pressure drop across housing 19 and cooler 31, thereby establishing the temperature of cool air flowing through conduit 33. The smaller orifice 35 is, the smaller the air pressure and temperature drop that occurs across cooler 31.
In some applications, cooler 31 may be adapted to perform only its basic cooling function and discharge the warm air flowing in conduit 34 directly to the atmosphere. However, in the present installation, cooler 31 not only supplies cool air to television camera 15 and housing 19, but also provides air for cooling and purging extension lens 17 and housing 20. This is accomplished by directing what would otherwise be wasted air from conduit 34 into orifice 36 and through passageway 37, the latter having a purging configuration at the exposed end of lens 18. Spent air is discharged to either the atmosphere or the interior of chamber through optical opening 38 in the end of lens housing 20.
Heat from chamber 10 that may penetrate housing 20 while in aperture 11 is continuously absorbed in sufficient quantity by the air flowing in passageway 37, thereby preventing heat damage to lens 17. Similarly, the air flowing through the purging configuration in passageway 37 prevents hot gases, dust and foreign matter from entering opening 38 and contacting or damaging lens element 18. The amount of cooling and purging that occurs is based on well known thermodynamic and fluiddynamic principles, respectively.
lt will be observed that housed television camera and lens assembly 13 is not mounted directly to aperture 11 or chamber wall 12 as in prior art installations. Instead, assembly 13 is mounted on powered operator 39 which positions lens 17 in aperture 11 and, together with control means 40, automatically retracts the lens from aperture 17 upon a predetermined reduction in air pressure downstream of regulator 29. In addition, control means 40 includes controls for manually extending and retracting lens 17 into and out of aperture 11.
The above noted mounting and control arrangement has several advantages. One, it prevents damage to the electro-optical components in assembly 13 from operating hazards due to a reduction or loss in the cooling and purging air supply. Further, it minimizes heat and vibration transmission form chamber 10 to the electro-optical components in assembly 13 because of the absence of a mounting member mass, thereby permitting reduced capacity of cooler 31 and vibration absorption means for camera 15, respectively. Moreover, it provides television camera and extension lens 17 with facilities to minimize maintenance, inspection and replacement downtime.
More specifically, powered operator 39 comprises support member 41 having a pair of parallel upturned flanges 42, said flanges located at an angle with chamber 10 directly below aperture 11. A base plate 43 integral with one end of support 41 is mounted on surface 44 which is preferably isolated from chamber 10. Two leveling bolts 45, one each located in a comer opposite base plate 43, are provided for aligning the optical axis of assembly 13 with the axis of aperture 11.
Powered operator 39 includes a grooved carriage 46 mounted movably along support flanges 42. Carriage 46 includes a pair of lateral upright supports 47 which are contoured to cradle camera housing 19 and otherwise dimensioned to position the aforesaid optical axis parallel to flanges 42 and centrally in aperture 11. Housing 19 is secured to carriage 46 by a pair of adjustable straps such as link chains 48. One end of each chain is slidably engaged with respective tightening lugs 49 at the opposite side of supports 47. This arrangement facilitates ease of assembly and disassembly of camera and lens assembly .13 with respect to carriage 46.
Powered operator 39 also includes means 50 for driving carriage 46 along support'fianges 42. Means 50 comprises an elongated threaded drive shaft 51 under carriage 46 which has one end supported rotatably in pillow block 52 and the end splined to speed reducer 53. Shaft 51 is threadably engaged with runner 54 which is attached to the underside of carriage 46. A reversible electric motor 55 is coupled to speed reducer 53 for rotating drive shaft 51 and powering carriage 46 in two directions.
Movement of carriage 46, and therefore assembly 13, is governed by control means 40 which is shown diagrammatically in FIG. 3. Control means 40 comprises an electric power source (not shown) fed over circuit 56 to reversing motor controller 57, the latter being connected to motor 55. A mode selector 58, operating on controller 57, provides manual extend, manual retract and automatic operating modes for powered operator 39.
A pressure switch 59 is used to detect the pressure or absence of sufficient air pressure for cooling and/or purging purposes. For this reason, it is also piped downstream of pressure below that established by regulator 29. These contacts are circulated with selector 58 to cause controller 57 to automatically retract carriage 46 during automatic mode of opera tion and to disable manual extend operation. Although not required for the preferred embodiment, pressure switch 59 contacts may also be circuited to affect automatic extension of carriage 46 upon restoration of the air pressure to a predeten mined level.
Control means 40 also includes limit switches 60, 61 which are mounted, for example, on a side of an upright flange 42 so as to be tripped by carriage 46 at its fully extended and fully retracted positions, respectively. Limit switches 60, 61 are wired with controller 57 to deenergize motor 55 at their respective carriage positions during all modes of operation.
Operation of the preferred embodiments will now be described.
Assume that compressed air is maintained at a predetermined pressure by regulator 29 and continuously applied to cooler 31 in sufficient quantity for cooling and purging purposes. Further, that the cooling air in conduit 33 flows through housing 19 and out of orifice 35, and that air in conduit 34 flows through passageway 37 and out of opening 38. Furthermore, that carriage 46 is in the fully extended position, limit switch 60 is tripped, and pressure switch 59 has detected the presence of sufficient air pressure for cooling and purging purposes.
Selector 58 normally maintains powered operator 39 in an automatic operating mode. Under the assumed conditions in this mode, operator 39 is deenergized and lens 17 is fully extended into aperture 11, thereby obtaining a full televised view of chamber 10 interior. However, when pressure switch 59 detects the absence of sufficient air pressure for cooling and purging purposes, powered operator 39 automatically moves assembly 13 to the fully retracted position. Thus, costly damage to television camera 15 and extension lens 17 is avoided.
When all of the assumed conditions prevail, except that carriage 46 is fully retracted rather than extended and limit switch 61 is tripped instead of switch 60, selector 58 may be held momentarily in a manual extend operating mode. Powered operator 39 becomes energized and moves assembly 13 toward chamber 10. Movement proceeds as long a selector 58 is held, or until carriage 46 trips limit switch 60 at the fully extended position. Should pressure switch 59 detect a deficiency in air pressure, powered operator 39 is disabled in the extend direction and automatically returned to the fully retracted position.
When the originally assumed conditions prevail, selector 58 may also be held momentarily in a manual retract operating mode. Powered operator 39 becomes energized and move away from chamber 10 until selector 58 is released, or until carriage 46 trips limit switch 61 in the fully retracted position.
What I claim:
1. ln apparatus having a television camera and extension lens assembly for televising the interior of an apertured hazardous chamber, said apparatus including means for cooling at leastone portion of said assembly, the improvement comprising:
a. powered operating means mounted independent of said chamber for positioning the extension lens axially relative said aperture and for retracting the lens therefrom, and
b. means responsive to a predetermined change in cooling or purging properties within said assembly for controlling the operation of means (a).
2. The apparatus of claim 1 wherein means (a) is adapted for both extending and retracting the lens into and out of said aperture.
3. The apparatus of claim 1 wherein means (b) is adapted to respond to a predetermined reduction in cooling or purging properties to effect lens retraction.
4. The apparatus of claim 1 including:
c. means acted on by means (a) movement and connected to control means (b) for limiting axial movement of the extension lens.
5. The apparatus of claim 1 wherein means (a) comprises:
i. a support member mounted independent of said chamber and alignable with the chamber aperture,
ii. a camera and a lens carriage mounted movably along the support member, and
iii. means operative under control of means (b) for driving said carriage along the support member.
6. ln apparatus for televising the interior of an apertured.
hazardous chamber, the combination comprising:
a. a television camera and extension lens assembly,
b. means for cooling or purging at least one portion of said assembly,
0. powered operating means mounted independent of said chamber for positioning the extension lens axially relative said aperture and for retracting the lens therefrom, and
d. means responsive to predetermined changes in cooling or purging properties within said assembly for controlling the operation of means (c).
7. Apparatus for televising the heated interior of a chamber comprising:
a. a television camera having an extension lens assembly attached thereto,
b. a housing surrounding said camera and said lens assembly,
c. means for circulating cooling air under pressure through the interior of said housing,
an adjustable support for (a) and (b) in which (a) and (b) are supported independently of said chamber in a predetermined position relative to an opening in said chamber, and
e. means associated with (d) responsive to a predetermined reduction in the pressure of cooling air circulating through said housing for retracting (a) and (b) from the predetermined position relative to the opening in said chamber 8. The apparatus of claim 7 in which at least a portion of the cooling air is discharged from said housing over the face of said lens assembly.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,609,236 Dated September 28 1971 Wesley H. Heilman Inventofls) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 3, line 72, after "is" insert 48 is anchored at one side of each support 47 and the other end of each chain is 1 Column 4, line 22, after "pressure" insert regulator 29 as is cooler 31 Pressure switch 59 includes adjustable contacts set to operate at a predetermined pressure line 64, "as long a" should read H as long as line 72, move" should read moves Signed and sealed this 9th day of May 1972.
(SEAL) fittest I EDWARD M.,FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents PC4050 USCOMM-DC wave-Pas 9 U 5, GOVERNMENT PRINTING DFFICE \fll 035U3l4