United State Patent (19) Hopkin (11 Patent Number: () Date of Patent: Aug. 23, 1988 54 MICROWAVE HIGHWAY PAINT DRYING APPARATUS 76 Inventor: Harry C. Hopkin, Rte. 5, Box 883, Williamton, N.C. 27892 (21) Appl. No.: 20,109 22 Filed: Feb. 27, 1987 51) Int. Cl.... EO1C 23/16; E01C 23/14 52 U.S. C.... 404/94; 404/95; 404/126; 239/1; 34/1; 118/5; 118/620; 427/. 1; 427/137; 427/421 58) Field of Search... 404/77, 79, 93-95, 404/126; 239/1; 34/1; 118/5, 620; 427/.1, 137, 421 (56) Reference Cited U.S. PATENT DOCUMENTS 3,018,704 1/1962 Searight... 404/94. 3,046,854 7/1962 Wilon...... 404/94 3,279,336 10/1966 Eaton et al.... 404/94. 3,472,200 10/1969 Gerling... 18/5 X 4,175,885 11/1979 Jeppon... 404/77 4,2,487 2/1981 Jeppon... 404/79 X 4,319,856 3/1982 Jeppon... 404/79 Primary Examiner-George A. Suchfield Aitant Examiner-John F. Letchford Attorney, Agent, or Firm-Darby & Darby (57) ABSTRACT A mobile paint application and microwave drying appa ratu ha a downwardly open hollow frame forming a microwave cavity movable over a urface on roller. The interior cavity of the frame i coated with micro wave aborbent material, a are the roller. The frame in the front and rear conform to the roller with a certain gap and end above the urface at a certain ditance. Tread extend between the front and rear roller on each ide and have a thickne which i greater than the gap and ditance o a to create a circuitou path from the cavity which block microwave radiation. A paint pray nozzle i located in the cavity and applie paint to the urface. Thi paint i rapidly dried by a microwave generator which i poitioned in the cavity and direct radiation onto the wet paint. 14 Claim, 2 Drawing Sheet
U.S. Patent Aug. 23, 1988 Sheet 1 of 2 4.7,773 ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ? Z
U.S. Patent Aug. 23, 1988 Sheet 2 of 2 N
1. MCROWAVE HIGHWAY PANT DRYING APPARATUS TECHNICAL FIELD Thi invention relate to the ue of microwave to dry liquid a they are applied to urface and, more particu larly, to the continuou drying of paint a it i applied to highway or other urface. Background Art It i well known to ue microwave radiation to cook or merely dry product which have exce moiture. For example, it i known to ue microwave radiation to dry recently harveted crop. An example of uch a ue of microwave i illutrated in U.S. Pat. No. 4,4,806, which iued to the preent inventor. The difficulty with any microwave equipment i that the radiation can be harmful to animal, including hu man. Thu, technique are required which allow the radiation to be directed where it i needed without reaching nearby animal or people, epecially the peo ple required to operate the equipment. When a mall quantity of tationary product i to be dried, it can be poitioned in a cloed container, e.g. a microwave oven, and afely expoed to the radiation. However, the prob lem i much more difficult when the product mut be moved through the microwave drying apparatu. In particular, the apparatu mut be open to allow product to move into and out of the apparatu, but microwave radiation mut be prevented from ecaping. Thi prob lem i olved according to U.S. Pat. No. 4,4,806, with repect to harveted grain moving on a conveyor belt, by introducing the grain and removing the grain from the microwave chamber through labyrinth eal. The road and highway of the country mut be. painted frequently with marking indicating dividing line, turn lane, cro walk and other afety ign. While thee marking are uually applied in the form of fat drying paint, the paint doe not dry intantly. Thu a portion of the road or highway mut be blocked off for a time ufficient to allow the paint to dry. Thi, however, can lead to traffic congetion. If the road i not blocked for a ufficient time to allow the paint to dry, vehicle traffic can mear the paint making it un ightly. Alo in ome intance the traffic will mar the marking to uch an extent that the afety meage i unclear, which could lead to accident. Variou method for accelerating the drying of high way paint are known from the prior art. For example, U.S. Pat. No. 3,018,704 of Searight teache the ue of a flame heater to preheat the pavement prior to applica tion of the paint. After the paint i applied, a radiant heater i ued to dry it. U.S. Pat. No. 3,472,200 of Gerling dicloe a combi nation of infrared and microwave heater mounted to a mobile highway painting apparatu for rapidly drying the paint. In the Gerling patent apparatu, the leakage of microwave i prevented through the ue of tiltable microwave cavitie, low-wave waveguide tructure, and hield which are epecially arranged to trap micro WaWe. Beide drying highway patent, it i alo known to ue drying apparatu to dry paint applied to other urface. U.S. Pat. No. 3,709,194 dicloe infrared apparatu for drying protective coating applied to the hull of a hip. Such an application of drying apparatu i of particular utility in the painting of room which cannot be conve O 20 40 60 2 niently kept out of ervice for extended period, e.g., hopital emergency room, dentit, office, etc. DISCLOSURE OF THE INVENTION The preent invention i directed to the microwave drying of paint a it i applied to a urface, while confin ing the microwave afely within the paint application tructure. Thi object i achieved in a imple manner by a combination of liding and rolling microwave hield. In an illutrative embodiment of the invention micro wave drying equipment i added to a mobile highway paint triping trailer towed by a truck. The microwave equipment i in the form of a four wheel vehicle with a relatively flat upper urface. Thi urface i made of, or it underide i lined with, a microwave aborbent mate rial. Alo extending down from the upper urface along it ide are fixed microwave aborbent hield. Thee are arranged o they are in ealing engagement with the upper urface and extend to the vicinity of the highway. Similar hield may alo extend from the front and back edge of the upper urface o a to form a generally encloed cavity below the upper urface. Alo, flexible hield of microwave aborbent material may extend from the upper urface into light contact with the road urface. Further, the wheel of the vehicle can be made in the form of roller which are covered with micro wave aborbent material to create rolling eal that increae the microwave ealing capacity of the cavity. A conventional paint tripe pray nozzle i upended from the underide of the upper urface of the vehicle into the cavity jut behind the front wheel. Thi nozzle applie the highway paint tripe to the pavement. Alo, located within the cavity are one or more microwave generator arranged to direct microwave radiation onto the paint tripe formed by the pray nozzle o a to dry it. In the embodiment deigned for applying a traight paint tripe, the front wheel are urrounded by a uni tary roll of microwave aborbent material that extend completely acro the front of the trailer to form a roll ing eal and the rear wheel may alo be provided with uch a rolling eal. In addition two tread of microwave aborbent material extend from a front wheel to a rear wheel on each ide of the paint pray nozzle. The tread allow mall bump in the roadway to be covered uch that no microwave leak out when they are paed over. In another embodiment for applying a curved paint tripe, the two front and two rear roller are eparately rotatable with repect to each to allow them to travel at different peed to affect a turn. However, the adjacent edge of the roll have a tongue and groove arrange ment to provide a eal. The combination of fixed microwave hield, backed up by rolling microwave eal and flexible hield, keep the microwave from ecaping and harming peronnel working on the paint tripe equipment or paing mo torit. While the ealing of the microwave cavity i not, and cannot be complete, i.e. with no opening, the open ing are o taggered with repect to each other that microwave, which travel in traight line, cannot e cape. The principle of the preent invention can alo be utilized to create a wall paint drying apparatu which i ueful in ituation where rapid paint drying i impor tant, e.g. in facilitie, uch a hopital emergency room, that cannot be taken out of ervice for long period of time. Thi ame device can be provided with an exhaut
3 ytem which allow fume created by the drying pro ce to be removed from the room. Such a ytem i ueful when the device i utilized in a cloed environ ment which may have to be occupied by ill people hortly after the painting ha been completed. BRIEF DESCRIPTION OF THE DRAWENGS The foregoing and other feature of the preent in vention will be more readily apparent from the follow ing detailed decription and drawing of illutrative embodiment of the invention in which: FIG. 1 i a ide view of a highway paint tripe appli cation vehicle according to the preent invention; FIG 2 i a top ectional view of the microwave dryer portion of the vehicle of FIG. 1 along line II-II; FIG. 3 i a ide ectional view of the microwave dryer portion of the vehicle of FIG. 2 along line III -III: FIG 4 i an enlarged partial ectional view of the interection of the roller of FIG. 2 along line IV-IV; and FIG5 i a ectional view of a miniaturized verion of the apparatu of FIG. 1 ued to paint and quickly dry wall. DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS FIG. i. illutrate a ide view of highway traffic mark ing equipment according to the preent invention. A pictured in FIG. 1, the equipment ha two major com ponent: a traffic marking vehicle 10 and a microwave paint tripe application and microwave drying appara tu 20 which i towed by the vehicle 10. The vehicle 10 may be of conventional deign, uch a the equipment old by Primo Univeral Corporation of Huntington, Pennylvania under the trademark WALD. Baically the vehicle 10 i a truck which ha a genera tor 12, paint upply tank 14 and a control panel 16 mounted on it rear. Thee vehicle, a conventionally equipped, include pray nozzle which apply highway paint tripe. In ome verion the tripe i applied ahead of the vehicle by a nozzle attached to a boom aembly 13. Such a nozzle i guided to the proper location by a wheel located at the end of boom 13. Additionally the paint pray nozzle may be located under the body of the truck and aociated with another roller boom. How ever, according to the preent invention, the paint i applied from the rear of the vehicle and within the interior of equipment 20. In order to make ure that the highway i clear of debri at location where the paint tripe i to be applied, a rotating bruh 17 i attached to the forward part of the truck body. An externai view of paint application and drying apparatu 20 will how only a flexible microwave ab orbing hield 22, which extend in all four direction from upper platform 21 of the device 20. Thi flexible hield 22 extend into contact with the pavement. The flexible hield may be made of a heavy fabric, e.g. can va, coated with a microwave aborbent material. The canva may have a particular hape defined by heavy metal wire 19 (FIG. 2) located in contact with hield 22. In applying a highway paint tripe, the vehicle move at a relatively low peed, for example 10 mile per hour. Thu there i relatively little wearing of the flexible hield 22 during a paint application proce. Thi a ure that it i difficult for microwave ued to dry the paint to ecape eaily. O 20 40 4. Within the apparatu 20 there are four wheel, two front 23, 24 and two rear, 26. The wheel, a bet een in FIG. 2, are actually in the form of large roller. Thee roller may be made of microwave aborbing material or maybe coated with uch material. A a reult thee wheel form additional microwave barrier within the cavity formed by the flexible hield 22. The wheel are upported by a rigid frame 27 which extend completely about the cavity and i attached to upper urface 21. FIG. 3 how that thi frame 27 extend to the vicinity of the highway, but doe not touch it, a doe the flexi ble hield 22. The interior portion of frame 27 are alo covered with microwave aborbing material. Toward the outer edge of the wheel 23-26 there are recee in which flexible tread 29 are received. FIG. 1 how that one tread extend from wheel 23 in the front to wheel in the rear. Similarly, a tread 29' extend from roller 24 in the front to roller 26 in the rear. Thee tread 29, 29' have a thickne which i equivalent to or greater than the gap between the bottom edge of frame 27 and the highway. Thu the rigid frame 27 and the tread 29, 29' form a primary eal to backup the flexible eal created by hield 22. The rigid hield 27 at the front and rear urface of apparatu 20 follow the curve of the front and rear roller a hown in FIG. 1. Thi allow the frame 27 to better cooperate with tread 29 in ealing microwave within the interior of vehicle 20. When it i deired to apply a paint tripe to the high way, one operator drive the vehicle along the highway at the proper peed and poition. The boom 13 may be ued by the operator to guide the proper poitioning of the vehicle 10. A econd operator, itting at control 16, tart the generator 12 to power the paint application proce. By operating the control 16, paint i delivered from tank 4 at high preure through a conduit 32 which enter apparatu 20. Conduit 32 pae behind the front roller to a pray nozzle 33 located jut above the highway urface. Paint i then prayed onto the high way in a conventional manner o a to form paint tripe 40 a hown in FIG. 2. In order to rapidly dry thi paint, two microwave generator 42, 43 are located after the pray nozzle 33 in poition to direct microwave energy onto the paint tripe. Thee microwave generator are of conventional deign and may be of the type dicloed in U.S. Pat. No. 3,472,200 of Gerling, the dicloure of which i incorporated herein by reference. The roller 23-26, the tread 29 and the rigid frame 27 all act together to form an interior microwave ealed chamber or cavity. In addition, a backup eal i formed by the flexible hield 22. A a reult, the micro wave generator 42, 43 may be operated within the cavity without cauing ignificant microwave leak age which would harm the operator itting at control 16 or would harn motorit in paing vehicle. Reference to FIG. 3 how that microwave within the cavity are blocked from vertical ecape by the upper urface 21 of the apparatu. Thi urface i made of or covered by microwave aborbing material. Laterally directed microwave are blocked in part by the roller, and the ide wall and end wall of frame 27. Since thi frame doe not touch the ground, a hown at A in FIG. 3, there i a poible path for the ecape of radiation. How ever, thi path i blocked by the tread 29, uch that microwave would have to travel a very circuitou path over the tread 29 and then down between the tread and wall 27. Since microwave travel in traight line, it i unlikely that the microwave could affect ecape by
5 that route. Neverthele, even if tray microwave did travel that path, they would be blocked by flexible hield 22. Tread 29 alo ha an additional benefit becaue it i made of relatively thick and flexible microwave aborb ing material or a material which i coated with micro wave aborbent material. Small bump or debri in the road (FIG. 3) will not break the eal. Rather, the tread will compre over the tone or bump without cauing the edge of the tread to rie up from the pave ment. Thu, the eal i maintained. In ituation where only a traight tripe i being laid down, roller 23 and 24, a well a roller and 26, can be one piece, repectively. Thi mean that the roller form ignificant hield to the ecape of microwave along both the front and rear edge of the apparatu 20. Since the operating peronnel it in the vicinity of con trol 16, they're provided with additional protection. Further, paing motorit are not likely to be in the vicinity of the microwave for any great period of time, o the danger to them from the ecape of microwave i very low. However, a vehicle traveling behind the equipment might tay in that poition for a coniderable period of time. In recognition of thi, the roller, 26 at the rear of the apparatu provide additional protec tion to the ecape of microwave in that direction. Fur ther, it hould be noted that the microwave generator direct their radiation principally toward the paint tripe to be dried and it i generally only the reflective radiation that i uceptible to ecape. Thu, varying the orientation of the microwave generator act to reduce the likelihood of the ecape of radiation from the appa ratu. It i frequently neceary to lay down highway tripe on curve. Thi would be difficult to do if the front and rear roller were unitary. Thu, a hown in FIG. 2, the roller can be eparate, uch that they may turn at dif ferent peed to follow a curved path. However, when thi i the cae the abutting roller 23, 24 and, 26 are given a tongue-and-groove contruction a hown in FIG. 4 in order to reduce the likelihood that microwave radiation will leak from between the two roller. In a ituation where ignificant curved motion i required by the apparatu 20, the roller 23-26 can be made to pivot about a horizontal axi. However, in uch a cae there i likely to be a gap between the roller to permit thi rotation. Thu, there will be ome acrifice in the front and rear microwave ealing affect in order to reduce the turning radiu of the apparatu. The length of the apparatu, a pictured in FIG. 2, i about ten feet. If the vehicle i travelling in the range of 5 to mile per hour, it i poible for the microwave generator to ufficiently dry the paint by the time it reache rear roller, 26. Conequently the roller do not mar or mear the paint. In winter weather condi tion thi drying affect can be improved by including preheating equipment of conventional radiant heater type in order to warm the highway prior to the applica tion of the paint tripe. The control for the microwave generator can be included in the main conventional control panel 16 for the equipment. Such control are capable of turning the paint application on and off to create an interrupted tripe along the highway and, if neceary or adviable, the microwave generator can be turned on and off in equence with thi paint application in order to both conerve energy and reduce the rik from radiation. Further, the power output of the microwave generator 5 10 60 6 can be controlled in repone to the vehicle peed uch that the power output i increaed with increaing peed. In ome cae, ice or now on the roadway cannot be removed by the bruh 17 and the application of heat by a radiant heater. In uch a ituation the paint application can be turned off and the whole unit moved along the path to be coated with paint. The microwave genera tor would then ait in melting any ice located on the pavement uch that during a econd pa the highway marking tripe could be effectively applied. Another alternative ue for the preent apparatu i for the removal of old highway paint. In uch a itua tion, the apparatu would be moved over the old paint and the microwave generator would be et at uch a high level a to evaporate or volatilize the old paint. If neceary, the exhaut ytem carried on the vehicle 10 could be ued to uck the volatilized paint fume from within the cavity, pa them through a filter 52 and dicharge them into the atmophere at exhaut 53. Such a uction line i hown in dotted line in FIG. 1 a ex haut conduit. A miniaturized verion 60 of the apparatu 20 hown in FIG. 1, i illutrated in FIG. 5. Thi unit i ueful for pray painting wall which mut be dried quickly. The unit 60 ha a handle 61 which may be utilized to manu ally move the device along a wall or to attach the unit to ome ort of upport device for moving the unit along the wall with mechanical aitance. The unit include wheel 63 which are urrounded by tread. Located exterior to the wheel and the tread i a fixed frame 67 which doe not come in contact with the wall 70, but which in combination with the tread form an interior rolling microwave eal. A flexible microwave hield upported by metal wire i poitioned outide the frame and doe extend into contact with wall 70. Thi flexible hield 69 provide backup for the interior hield and aure that microwave do not leak. The hield tructure reult in a cavity 72 in which a paint pray nozzle 74 and a microwave generator 76 are located. The paint pray nozzle 74 applie a paint coat ing to the wall 70 a the unit i moved upward a hown in FIG. 5. Thi upward motion then bring the micro wave generator 76 over the area which ha jut been painted o a to rapidly dry it before the rear ealing roller 63 reache the area. A upply of paint 80 which i under preure, i connected to nozzle 74 through a flexible conduit 82. In addition, the interior cavity i connected by a conduit 84 to a vacuum unit 86. Thi vacuum unit uck out any noxiou vapor from the cavity 72 and direct them outide the room being painted. With thi arrangement, a room, for example, a hopi tal emergency room, can be rapidly painted and the paint dried without the creation of noxiou fume. Thu the room can be reoccupied even by thoe uffering repiratory illnee in a relatively hort period of time. While the invention ha been particularly hown and decribed with reference to preferred embodiment thereof, it would be undertood by thoe killed in the art that variou change in form and detail may be made therein without departing from the pirit and cope of the invention. I claim: 1. A mobile microwave drying apparatu compriing a generally hollow box haped frame having a upper wall, two ide wall, a front wall and a rear wall, but which i open on the bottom, the interior ur
7 face of the frame being covered with a microwave aborbent material and forming a microwave cav ity, front and rear roller pivotally attached to the ide wall of aid frame adjacent the front wall and rear wall, repectively, uch that aid frame i mobile over a urface contacted by aid roller, the frame being paced from the urface by a certain ditance; at leat one tread extending about aid front and rear roller, aid tread being covered with microwave aborbent material, the thickne of aid thread being greater than the certain ditance o a to ubtantially eliminate any traight path from the microwave cavity to the exterior of the frame, except through the urface contacted by aid rol ler; a fluid pray nozzle located within the microwave cavity for praying fluid on the urface; and at leat one microwave generator for directing micro wave radiation onto the fluid prayed on the ur face and drying the fluid. 2. A mobile microwave drying apparatu a claimed in claim 1 wherein the front and rear wall of aid frame conform generally to the hape of aid front and rear roller with a certain gap, and wherein the thiokne of the tread i le than aid gap. 3. A mobile microwave drying apparatu a claimed in claim 1 further including a flexible microwave hield extending from the upper wall into contact with the urface outide of the front, rear and two ide wall. 4. A mobile microwave drying apparatu a claimed in claim 3 wherein the flexible microwave hield con prie a heavy fabric material, a coating of microwave aborben material on the interior of the fabric and wire tay for generally haping the fabric. 5. A mobile microwave drying apparatu a claimed in claim 1 wherein there are two front roller, two rear roller and two tread, each tread extending about re pective one of the front and rear roller adjacent each ide wall. 6. A mobile microwave drying apparatu a claimed in claim 5 wherein the adjacent edge of the two front and two rear roller form a tongue and groove connec tion in that a projection from the adjacent edge of one roller extend into a rece in the adjacent edge of the other. 7. A mobile microwave drying apparatu a claimed in claim 1 further include a vacuum exhaut line con nected to the microwave cavity for removing gae formed in the cavity a a reult of the drying of the fluid. 8. A mobile microwave drying apparatu a claimed in claim 1 wherein the fluid i paint. 10 40 8 9. A mobile microwave drying apparatu a claimed in claim 8 wherein the apparatu i a trailer for applying highway marking tripe to a pavement and wherein the trailer i pulled by a motor vehicle. 10. A mobile microwave drying apparatu a claimed in claim 8 wherein the apparatu i a wall painting de vice manually moved about a wall, and the fluid i paint. 11. A mobile microwave drying apparatu a claimed in claim 10 further including a vacuum exhaut line connected to the microwave cavity for removing gae formed in the cavity a a reult of the drying of the paint. - 12. A mobile microwave drying apparatu a claimed in claim 11 further including a filter for filtering the removed gae and an exhaut for dicharging the fil tered gae to the atmophere. 13. A mobile microwave drying apparatu a claimed in claim 1 wherein aid roller are covered with a coat ing of microwave aborbent material. 14. A mobile microwave highway paint applying and drying apparatu, compriing a generally hollow box-haped trailer frame with upper, front, rear and two ide wall, and an open bottom, the interior urface of the frame being covered with a microwave aborbent material and forming a microwave cavity; front and rear roller pivotally mounted to the ide wall of aid frame adjacent the front and rear wall, repectively, uch that aid trailer i mobile over a highway at a peed of up to mile per hour, the front and rear wall of aid frame con forming generally to the hape of aid front and rear roller with a certain gap, the frame being paced from the urface by a certain ditance; at eat one tread extending about aid front and rear roller, aid tread being covered with microwave aborbent material, the thickne of aid tread being greater than the gap ditance o a to ubtantially eliminate any traight path from the microwave cavity to the exterior of the frame, except through the highway; a paint pray nozzle located within the microwave cavity for praying paint marking onto the high way; at leat one microwave generator located within the microwave cavity for directing microwave radia tion onto the paint applied to the highway and drying the paint; and a flexible microwave hield in the from of a kirt of flexible material coated on the interior with micro wave aborbent material, aid kirt extending from the upper wall of aid frame into contact with the highway outide of the front, rear and ide wall. 3.2 x 22