JPH0616868B2 - Method and apparatus for coating deformed rebar - Google Patents

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は鉄筋コンクリートに使用されるふしまたはリブ
付き等のＲＣ用もしくはＰＣ用異形鉄筋の塗装方法およ
び塗装装置に関する。Description: TECHNICAL FIELD The present invention relates to a coating method and coating apparatus for RC or PC deformed rebars such as those with noses or ribs used for reinforced concrete.

（従来の技術） 近来海洋コンクリート構造物が多くなり、鉄筋コンクリ
ート内に包蔵して使用する鉄筋でも、塩分からの防食が
必要とされている。また特に海洋コンクリート構造物に
限らず、川砂の不足からコンクリートに海砂の一部混入
その他各種要因による塩害が生じつつある。かかる現状
から、防食のため鉄筋にエポキシ系粉体塗料を塗装した
うえで使用することが試みられつつある。〔塗装鉄筋の
設計・施工・品質基準（案）・同解説；日本道路協会刊
行，昭和５９年２月〕 鉄筋については、配筋時に曲げ等が加えられる際に塗装
がはがれず、かつ異形性を保有せしめるため可及的に薄
い均一な被膜を形成するのが好ましいが、これにはエポ
キシ系粉体塗料の各種塗装方法の中で静電塗装が適して
いるとされている。(Prior Art) The number of marine concrete structures has increased in recent years, and even the reinforcing steel contained in reinforced concrete is required to be protected from salt. In addition to sea concrete structures, salt damage is occurring due to the lack of river sand and the inclusion of sea sand in concrete and various other factors. Under such circumstances, it has been attempted to coat the reinforcing bar with an epoxy-based powder coating for use before use. [Design / Construction / Quality Standards for Painted Reinforcement (Draft) / Commentary: Published by Japan Road Association, February 1984] Reinforcing bars do not peel off when bending is applied during re-arrangement It is preferable to form a film as thin and uniform as possible in order to retain the property, but electrostatic coating is said to be suitable for this purpose among various coating methods of epoxy powder coatings.

上記静電塗装方法を用いた異形鉄筋の塗装では、まず鉄
筋を電気炉，熱風炉等に入れ、所定時間かけて２３０〜
２５０℃にまで昇温させて予熱し、しかる後予熱された
鉄筋の表面に静電噴射ガンで粉体塗料を吹きつけるよう
にする。In the coating of deformed reinforcing bars using the above electrostatic coating method, first, the reinforcing bars are placed in an electric furnace, a hot air oven, etc.
The temperature is raised to 250 ° C. and preheated, and then the powder paint is sprayed onto the surface of the preheated rebar by an electrostatic spray gun.

（従来技術に存する問題点） 上記従来方法は、電気炉，熱風炉等を用いるため、全断
面加熱とならざるを得ず、従つて所定温度までの予熱に
時間がかかり生産性が低く、かつ表面処理であるのに関
連の薄い内部まで表面と同一の温度まで加熱するのでエ
ネルギーの無駄が多い。(Problems existing in the prior art) Since the above-mentioned conventional method uses an electric furnace, a hot-air stove, and the like, it is inevitable that the entire cross-section is heated, and thus preheating to a predetermined temperature takes time and productivity is low, and Even though it is a surface treatment, it heats up to the same temperature as the surface up to the related thin interior, so much energy is wasted.

その上、電気炉等へは一度に複数本入れて同時加熱する
が、次工程の粉体塗料吹きつけは１本ずつ施さざるを得
ず、連続的なライン生産態勢をとることができない。こ
れがため粉体塗料吹きつけ時の前後関係で温度差が生
じ、膜厚に不均一が生じたりピンホールができ易く、品
質にばらつきが多い。かかる現況から、特殊な場合を除
き、塗装異形鉄筋は未だ普及の段階に至らず、高品質の
塗装異形鉄筋を低コストで大量生産可能な方法の確立が
希求されていた。Moreover, a plurality of electric furnaces and the like are put into the electric furnace at the same time and heated at the same time, but the powder coating material is sprayed one by one in the next step, so that a continuous line production system cannot be prepared. For this reason, a temperature difference occurs before and after the powder coating material is sprayed, the film thickness becomes uneven, pinholes are easily formed, and the quality varies widely. Under these circumstances, except for special cases, the painted deformed bar has not reached the stage of widespread use, and there has been a demand for establishment of a method capable of mass-producing high-quality painted deformed bar at low cost.

（発明の目的） 本発明はふしまたはリブ付き等の異形鉄筋にエポキシ系
粉体塗料を静電塗装する場合の、高品質かつ低コストで
大量生産が可能な塗装方法および塗装装置を提供するこ
とを目的とする。(Object of the Invention) The present invention provides a coating method and a coating apparatus capable of mass production with high quality and low cost when electrostatically coating an epoxy powder coating on a deformed reinforcing bar such as a rib or a rib. With the goal.

（第一発明の構成） 本願第一発明の構成は、 (1)前処理に付したふし付き，リブ付き等の異形鉄筋を
予熱し、その表面にエポキシ系粉体塗料を静電塗装する
場合において、 (2)上記異形鉄筋を軸方向送りしつつ誘導加熱手段によ
り所定予熱温度よりも１０〜２０℃高温に加熱のうえ、 (3)送り速度と異形形状とから定まる表面均熱までの所
定時素後に異形鉄筋の表面へエポキシ系粉体塗料を静電
噴射するようにし、 (4)次いで可及的に少数配置した送りローラと塗料被覆
異形鉄筋表面との接触点に冷却水の細流を流すようにし
て搬送し、 (5)少なくとも粉体塗料硬化後に塗装鉄筋の表面を水冷
するようにした ことを特徴とする異形鉄筋の塗装方法にある。(Structure of the first invention) The structure of the first invention of the present application is (1) in the case of preheating deformed rebar having a pretreatment, such as with ribs and ribs, and electrostatically coating the surface thereof with an epoxy powder coating material. (2) While heating the deformed bar axially in the axial direction, the induction heating means heats the deformed bar to a temperature higher than a predetermined preheating temperature by 10 to 20 ° C., and (3) a predetermined heating up to surface soaking determined by the feeding speed and the deformed shape. Epoxy powder coating is electrostatically sprayed onto the surface of the deformed rebar after a certain period of time. (4) Next, a small stream of cooling water is applied to the contact point between the feed roller and the paint-covered deformed rebar surface arranged as few as possible. (5) The coating method for deformed rebar is characterized in that (5) the surface of the coated rebar is cooled with water at least after the powder paint is cured.

（第二発明の構成） 而して上記第一発明を実施するための本願第二発明の構
成は、 (1)異形鉄筋を軸方向送りするローラ群，送り通路に沿
つて設けられた誘導加熱コイル，複数基の静電噴射ガン
および冷却ジヤケツトから構成され、 (2)上記誘導加熱コイルと静電噴射ガンとの配置間隔を
送り速度と異形形状とから定まる所定間隔に設定し、 (3)上記複数基の静電噴射ガンは送り通路の周方向に均
等角度で分散配置されるとともに、送り通路斜め後方か
ら所定角度をもつて送り通路の一点に照準を集中する如
く設定され、 (4)当該静電噴射ガンと上記冷却ジヤケツトとの配置間
隔は少なくとも異形鉄筋表面に付着した粉体塗料が硬化
可能な時間以上の送り時間経過距離とし、 (5)その間に配置されて上方周面に接触する異形鉄筋を
搬送可能な単数もしくは複数の送り用ローラは冷却水ノ
ズルを具えていて、当該冷却水ノズルが送り方向後方側
からた駆動ローラの上方周接線沿いに冷却水の細流を噴
流可能に設定されていること を特徴とする異形鉄筋の塗装装置にある。(Structure of Second Invention) Therefore, the structure of the second invention of the present application for carrying out the first invention is as follows: (1) A group of rollers for axially feeding the deformed rebar, and induction heating provided along the feed passage. It is composed of a coil, a plurality of electrostatic spray guns and a cooling jacket. (2) The interval between the induction heating coil and the electrostatic spray gun is set to a predetermined interval determined by the feed speed and the irregular shape, (3) The plurality of electrostatic injection guns are arranged at equal angles in the circumferential direction of the feed passage, and are set so as to concentrate the sighting at one point of the feed passage at a predetermined angle from diagonally behind the feed passage, (4) The distance between the electrostatic spray gun and the cooling jacket is at least the feed time elapsed distance that is longer than the time during which the powder coating adhered to the surface of the deformed reinforcing bar can be cured, and (5) is placed between them and contacts the upper peripheral surface. A single piece that can carry deformed rebar In addition, the plurality of feed rollers are equipped with a cooling water nozzle, and the cooling water nozzle is set to be capable of jetting a small stream of cooling water along the upper circumferential tangent of the drive roller from the rear side in the feeding direction. There is a coating device for deformed rebar.

（発明の作用） 本発明は、誘導加熱される異形鉄筋表面の、誘導加熱の
特性と鉄筋の異形性に起因する加熱直後の不均一温度を
塗料吹きつけ時に適正所定温度に均一化する作用、異形
鉄筋表面への塗料吹きつけを周方向で均一とする作用、
塗料吹きつけ後の鉄筋表面を当該塗料が硬化するまでの
間を非接触に近い状態で搬送する作用および適正時間後
に塗装鉄筋を水冷して塗装工程時間を短縮する作用を発
揮する。(Operation of the invention) The present invention, the surface of the deformed reinforcing bar to be heated by induction, the effect of uniformizing the non-uniform temperature immediately after heating due to the characteristic of induction heating and the deformity of the reinforcing bar to a proper predetermined temperature at the time of spraying the paint, The action of making the paint spray on the surface of the deformed bar uniform in the circumferential direction,
It exerts an effect of transporting the surface of the reinforcing bar after spraying the coating material in a non-contact state until the coating material hardens, and an effect of shortening the coating process time by cooling the coated reinforcing bar with water after an appropriate time.

（実施例） 本発明を第１図（ａ）〜（ｄ）に示す実施例に従つて以
下に詳述する。(Example) The present invention will be described in detail below with reference to an example shown in Figs. 1 (a) to (d).

異形鉄筋は本発明実施に際し、前処理としてシヨツトプ
ラストによる錆落しが施される。次いで異形鉄筋は第１
図（ａ）の塗装ラインＰＬに搬入される。When the present invention is carried out, the deformed bar is subjected to rust removal by a shot plast as a pretreatment. Next deformed rebar
It is carried into the coating line PL shown in FIG.

塗装ラインＰＬにおいて、１は加熱ゾーン，２は均熱ゾ
ーン，３は複数基の静電噴射ガン，４は塗料硬化ゾー
ン，５は冷却ジヤケツトである。また加熱ゾーン１の図
示左側には異形鉄筋Ｗを上記加熱ゾーン１へ送り込む複
数対の送り込み用駆動ローラ６が、加熱ゾーン１の図示
右側と上記静電噴射ガン３の後述する照準点ａとの間の
均熱ゾーン２には加熱ゾーン１を通過した異形鉄筋を上
方周面で受ける自由回転可能な受けローラ７が、さらに
上記静電噴射ガン３と冷却ジヤケツトとの間の塗料硬化
ゾーン４には複数の送り用ローラ８が設けられていて、
異形鉄筋は上記送り込み用駆動ローラ６および送り用ロ
ーラ８の矢印方向への回動により塗装ラインＰＬ上を矢
印Ｌ方向へ軸方向送りされ、加熱ゾーン１から冷却ジヤ
ケツト５まで順次所定の送り速度で送られる。In the coating line PL, 1 is a heating zone, 2 is a soaking zone, 3 is a plurality of electrostatic spray guns, 4 is a paint curing zone, and 5 is a cooling jacket. On the left side of the heating zone 1 in the drawing, a plurality of pairs of feeding drive rollers 6 for feeding the deformed bar W to the heating zone 1 are provided. In the soaking zone 2 between them, a freely rotatable receiving roller 7 that receives the deformed reinforcing bar that has passed through the heating zone 1 on its upper peripheral surface is further provided in the paint curing zone 4 between the electrostatic spray gun 3 and the cooling jacket. Is provided with a plurality of feed rollers 8,
The deformed rebar is axially fed in the direction of arrow L on the coating line PL by the rotation of the feeding drive roller 6 and the feeding roller 8 in the direction of the arrow, and from the heating zone 1 to the cooling jacket 5 at a predetermined feeding speed. Sent.

上記加熱ゾーン１には本実施例では所定間隔を隔ててそ
れぞれ多巻された２個のコイルＣ１・Ｃ２が配設されて
おり、当該コイルＣ１・Ｃ２それぞれは図示しない所定
出力・周波数からなる加熱電源に接続されており、送り
込み用駆動ローラ６により入側から送り込まれる異形鉄
筋をコイルＣ１・Ｃ２それぞれを通過する間に表面加熱
し、その加熱表面の最高温を示す部分……通常ふし等の
突出端が昇温しやすい……の温度が予熱所定温度（例え
ば２３０〜２５０℃とされている）より１０〜２０℃高
温を示すまで加熱可能に設定される。In this embodiment, two coils C1 and C2, each of which is multi-turned at predetermined intervals, are arranged in the heating zone 1, and each of the coils C1 and C2 is heated by a predetermined output and frequency (not shown). The deformed rebar, which is connected to the power supply and is fed from the entrance side by the feed driving roller 6, heats the surface while passing through the coils C1 and C2, and shows the maximum temperature of the heated surface. The temperature at which the protruding end easily rises is set to be able to be heated until it shows a temperature higher by 10 to 20 ° C. than a predetermined preheating temperature (for example, 230 to 250 ° C.).

上記均熱ゾーン２は加熱ゾーン１を出た異形鉄筋の不均
一に昇温している表面が、熱伝導と放冷とで本体，ふし
等を問わずほぼ均一な予熱所定温度になるに必要な時間
経過を得るに適切な如く、異形鉄筋の形状……直径，ふ
しまたはリブの形状，質量等……と送り速度との関係か
ら長さが設定される。The soaking zone 2 is required so that the unevenly heated surface of the deformed reinforcing bar exiting the heating zone 1 reaches a substantially uniform preheating temperature due to heat conduction and cooling, regardless of the body or the bedding. The length is set based on the relationship between the shape of the deformed rebar, the diameter, the shape of the ribs or ribs, the mass, etc., and the feed rate, as appropriate to obtain a certain amount of time.

上記複数基の静電噴射ガン３は、本実施例では塗装ライ
ンＰＬの上方に１基３イが，下方に２基３ロおよび３ハ
が設けられており、当該静電噴射ガン３イ，３ロおよび
３ハそれぞれは全て照準点ａを均熱ゾーン２の終点と
し、例えば第１図（ｂ）に示す如く３イは塗装ラインＰ
Ｌの鉛直面上にあつて４５゜の角度をもつて送り方向斜
め後方から、また３ロおよび３ハそれぞれは上記３イに
対しかつ相互に１２０゜の角度を維持して送り方向斜め
後方４５゜の角度から、それぞれ上記照準点ａにノズル
を向けて配置されている。In the present embodiment, the plurality of electrostatic spray guns 3 are provided with one group 3a above the coating line PL and two groups 3b and 3c below, respectively. All of 3B and 3C have the aiming point a as the end point of the soaking zone 2. For example, as shown in FIG.
On the vertical plane of L, there is an angle of 45 ° from the rear in the feed direction, and 3b and 3c are obliquely rearward in the feed direction with respect to the above 3a and maintaining an angle of 120 ° with each other. The nozzles are arranged so as to face the aiming point a from the angle of °.

上記塗料硬化ゾーン４は上記静電噴射ガン３により異形
鉄筋表面へ付着せしめられた粉体塗料が溶融して硬化す
るには少なくとも４５秒、好ましくは６０秒必要であ
り、その間非接触状態を維持することが望ましいが、異
形鉄筋の長さ上から非接触状態での送りは困難であるた
め、当該塗料硬化ゾーン４内に単数もしくは複数の送り
用ローラ８が設けらることとなる。It takes at least 45 seconds, preferably 60 seconds, for the powder coating adhered to the surface of the deformed rebar by the electrostatic spray gun 3 to melt and cure in the coating curing zone 4, while maintaining the non-contact state during that period. However, since it is difficult to feed the deformed rebar in a non-contact state due to its length, a single or a plurality of feed rollers 8 are provided in the paint curing zone 4.

上記送り用ローラ８は上方周面が塗装ラインＰＬとなる
如く配置され、当該送り用ローラ８それぞれには９とし
て示す冷却水噴射ノズルが付設される。当該冷却水噴射
ノズル９は第１図（ｂ）および（ｃ）に示す構成からな
り、送り方向後方側から送り用ローラ８の上方周面の略
接線方向に沿うが如き冷却水の細流を噴射可能に設定さ
れ、送り用ローラ８の上方周面と粉体塗料が付着してい
る移動中の異形鉄筋との接触点を瞬時冷却水で冷却し、
溶融状態にある塗料の表面を一時的に固化して送り用ロ
ーラ８への付着を防止するように構成してある。The feed rollers 8 are arranged such that the upper peripheral surface thereof becomes the coating line PL, and each of the feed rollers 8 is provided with a cooling water jet nozzle indicated by 9. The cooling water jet nozzle 9 has the structure shown in FIGS. 1B and 1C, and jets a narrow stream of cooling water from a rear side in the feeding direction along a substantially tangential direction of an upper peripheral surface of the feeding roller 8. The contact point between the upper peripheral surface of the feed roller 8 and the deformed reinforcing bar to which the powder coating material is attached is cooled with instantaneous cooling water.
The surface of the molten coating material is temporarily solidified to prevent the coating material from adhering to the feed roller 8.

上記冷却ジヤケツト５は上記塗料硬化ゾーン４を通過し
て表面の塗料が硬化した異形鉄筋が、未だかなり高い温
度を維持しているので、これを順次全周方向から水冷し
て塗装ラインＰＬ外に搬出し易くするため、塗料硬化ゾ
ーン４の前方に設けられる。In the cooling jacket 5, the deformed rebar whose surface paint has hardened by passing through the paint hardening zone 4 still maintains a considerably high temperature. It is provided in front of the paint curing zone 4 for easy transportation.

本発明者は本発明の効果を確認するため、各種の実験を
行つた。その一部を以下に開示する。The present inventor conducted various experiments in order to confirm the effect of the present invention. Some of them are disclosed below.

〔実験例．１〕 加熱終了から均熱までに要する時間の確認実験 ○供試体；ＪＩＳ．Ｇ３１１２規格品 ○実験方法；第１図（ａ）に示される塗装ラインを用
い、各種径の異形鉄筋を誘導加熱コイル内を通過させて
最高昇温を示す部分における加熱温度を種々かえて加熱
したのち放冷し（塗装せず）、それぞれ全表面均一温度
となるまでに要する時間および冷却特性曲線を求めた。[Experimental example. 1] Confirmation experiment of time required from completion of heating to soaking ○ Specimen; JIS. G3112 standard product ○ Experimental method: Using the coating line shown in Fig. 1 (a), deformed rebars of various diameters were passed through the induction heating coil and heated at various heating temperatures in the part showing the highest temperature rise. Then, it was allowed to cool (without coating), and the time required until the temperature became uniform on the entire surface and the cooling characteristic curve were obtained.

ただし、誘導加熱電源は出力；８０KW、周波数；１５０
KHzであつた。However, the induction heating power supply output: 80KW, frequency: 150
It was KHz.

○実験結果；第２図に示すとおりであつた。図は全表面
均一温度となつた時点を基準時に設定してある。曲線に
付した記号・番号はそれぞれ供試体の規格呼び名を示
す。-Experimental results: As shown in Fig. 2. In the figure, the reference time is set at the time when the temperature of the entire surface becomes uniform. The symbols and numbers attached to the curves indicate the standard name of the specimen.

上記実験結果から、径差に拘わらず３０秒以内で全表面
均一温度が得られることが確認された。From the above experimental results, it was confirmed that a uniform surface temperature could be obtained within 30 seconds regardless of the diameter difference.

〔実験例．２〕 塗装結果に及ぼす予熱（均一時の）温度の決定実験 ○供試体；ＪＩＳ．Ｇ３１１２．Ｄ１６ ○実験方法；上記と同様に塗装ラインを用い、供試体の
予熱温度を種々かえて塗装を施し、塗装後の供試体を前
記「塗装鉄筋の試験方法（案）」に記載に則した各種試
験に付し、その結果を調査した。[Experimental example. 2] Experiment to determine the preheating (when uniform) temperature that affects the coating results ○ Specimen; JIS. G3112. D16 ○ Experimental method: A coating line was used in the same manner as above, and coating was performed by changing the preheating temperature of the specimen, and the specimen after coating was subjected to various tests in accordance with the above-mentioned "Test method (draft) for coated rebar". It was submitted to a test and the results were investigated.

ただし、各供試体の塗装膜厚は１９０〜２５０μ，塗装
後は水冷を施さず自然放冷とした。However, the coating film thickness of each sample was 190 to 250 μm, and after coating, it was naturally cooled without water cooling.

○実験結果；別紙の第１表に示すとおりであつた。同表
における○印は上記試験基準に合格、△印は不合格を示
す。-Experimental results: As shown in Table 1 of the attached sheet. In the table, ◯ marks pass the above test standards, and Δ marks indicate failure.

上記実験結果から、一般に静電塗装では２３０〜２５０
゜Ｃとされている予熱温度よりも１０〜２０゜Ｃ高温で
も良好な結果が得られ、かつ高温予熱限界はほぼ２６０
゜Ｃであることが確認された。From the above experimental results, generally 230-250 in electrostatic coating.
Good results were obtained even at 10 to 20 ° C higher than the preheating temperature which is said to be ° C, and the high temperature preheating limit was about 260.
It was confirmed to be ° C.

〔実験例．３〕 塗料吹きつけから水冷までの時間条件の設定実験 ○供試体；ＪＩＳ．Ｇ３１１２．Ｄ１６ ○実験方法；上記と同様に塗装ラインを用い、予熱温度
を２６０゜Ｃに一定とした供試体に塗料を吹きつけ、塗
料吹きつけ後の供試体に時間条件を種々かえて水冷し、
曲げ試験に付すとともに、ゲル分率を調査した。[Experimental example. 3] Setting experiment of time condition from spraying of paint to water cooling ○ Specimen; JIS. G3112. D16 ○ Experimental method: A coating line was used in the same manner as above, and the coating material was sprayed onto the specimen whose preheating temperature was constant at 260 ° C, and the specimen after spraying the coating material was water-cooled under various time conditions.
The gel fraction was investigated along with the bending test.

○実験結果；別紙の第２表に示すとおりであつた。同表
における○印は上記試験による基準に合格、☆は僅かな
クラツクが確認されたものである。○ Experimental results: As shown in Table 2 of the attached sheet. In the table, the ○ marks pass the criteria of the above test, and the ☆ marks show a slight crack.

上記実験結果から、塗料吹きつけから水冷までの時間は
少なくとも６０秒以上経過後を適切とすることが確認さ
れた。From the above experimental results, it was confirmed that the time from spraying the paint to cooling with water was appropriate after at least 60 seconds had elapsed.

〔その他の実験〕[Other experiments]

上記の他、各種の実験を行つたが、塗料膜厚の均一化に
は、下記条件が最適であることを見いだした。In addition to the above, various experiments were conducted, and it was found that the following conditions are optimal for uniforming the paint film thickness.

★供試体・ガン間の距離；３００mm程度 ★静電塗装ガンの数；３〜４基 ★静電塗装ガンの角度；９０゜＞４５゜（送り方向後方
から前方へ向けて） ★粉体塗料吐出量；５０ｇ／分（１ガン当り） ★印可電圧；−８０ＫＶ 尚、上記いずれの実験例においても、塗装後の供試体に
ピンホールは認められなかつた。★ Distance between specimen and gun: about 300mm ★ Number of electrostatic coating guns: 3 to 4 ★ Angle of electrostatic coating guns: 90 °> 45 ° (from the back to the front in the feed direction) ★ Powder coating Discharge rate: 50 g / min (per gun) * Applied voltage: -80 KV In any of the above experimental examples, no pinhole was observed in the coated sample.

（発明の効果） 本発明を実施することにより、ふしまたはリブ付き等異
形鉄筋への高品質のエポキシ系粉体塗料静電塗装を短時
間，低コストかつ大量生産方式で施すことが可能とな
り、海洋コンクリート構造物は勿論のこと一般鉄筋コン
クリート構造物への使用の普及が促進されることとな
り、鉄筋コンクリート構造物の耐腐食性を格段に向上す
るので、極めて顕著な効果をす。(Effects of the Invention) By carrying out the present invention, it becomes possible to apply high-quality epoxy powder paint electrostatic coating on deformed reinforcing bars such as those with ribs or ribs in a short time at low cost and in a mass production system. The use of not only marine concrete structures but also general reinforced concrete structures will be promoted, and the corrosion resistance of reinforced concrete structures will be markedly improved.

また、従来では予熱時間が長時間にわたるため、ＰＣ用
異形鉄筋は機械的性質の劣化を来すとして静電塗装適用
は全く考えられていなかつたが、本発明では予熱が極端
に短時間で済むので、機械的性質の低下を惹起する虞な
く塗装し得ることとなり、同時にＰＣ鉄筋コンクリート
構造物の耐腐食性の向上にも資するものとして有用性が
甚大である。Further, conventionally, since the preheating time is long, the deformed rebar for PC is not considered to be applied to the electrostatic coating because the mechanical properties are deteriorated. However, in the present invention, the preheating is extremely short. Therefore, it can be coated without fear of causing deterioration of mechanical properties, and at the same time, it is very useful as a contribution to improvement of corrosion resistance of the PC reinforced concrete structure.

【図面の簡単な説明】 第１図（ａ）は本発明の一実施例装置の正面図、第１図
（ｂ）は静電噴射ガンの配置例を示す上面図、第１図
（ｃ）および（ｄ）はそれぞれ本発明実施例装置に使用
される送り用ローラの正面図および側面図、第２図は
〔実験例．１〕における各供試体の放冷による温度低下
状態を示す線図である。 Ｗ……異形鉄筋 Ｃ１，Ｃ１……誘導加熱コイル ３……静電噴射ガン ５……冷却ジヤケツト ６……送り込み用駆動ローラ ７……受けローラ ８……送り用ローラ ９……冷却水ノズル BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is a front view of an apparatus according to an embodiment of the present invention, FIG. 1 (b) is a top view showing an arrangement example of an electrostatic spray gun, and FIG. 1 (c). And (d) are a front view and a side view, respectively, of the feed roller used in the apparatus of the embodiment of the present invention, and FIG. FIG. 1 is a diagram showing a temperature decrease state of each specimen in FIG. 1] due to cooling. W ... Deformed bar C1, C1 ... Induction heating coil 3 ... Electrostatic spray gun 5 ... Cooling jacket 6 ... Feeding drive roller 7 ... Receiving roller 8 ... Feeding roller 9 ... Cooling water nozzle

フロントページの続き (51)Int.Cl.⁵ 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０５Ｄ 7/24 ３０１ Ａ 8720−4Ｄ Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B05D 7/24 301 A 8720-4D

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】前処理に付したふし付き，リブ付き等の異
形鉄筋を予熱し、その表面にエポキシ系粉体塗料を静電
塗装する場合において、上記異形鉄筋を軸方向送りしつ
つ誘導加熱手段により所定予熱温度よりも１０〜２０℃
高温に加熱のうえ、送り速度と異形形状とから定まる表
面均熱までの所定時素後に異形鉄筋の表面へエポキシ系
粉体塗料を静電噴射するようにし、次いで可及的に少数
配置した送りローラと塗料被覆異形鉄筋表面との接触点
に冷却水の細流を流すようにして搬送し、少なくとも粉
体塗料硬化後に塗装鉄筋の表面を水冷するようにしたこ
とを特徴とする異形鉄筋の塗装方法。1. In the case of preheating a deformed rebar having a pretreatment, a rib or the like, and electrostatically coating an epoxy powder coating on the surface of the deformed rebar, induction heating is performed while the deformed rebar is fed in the axial direction. 10 to 20 ° C higher than the predetermined preheating temperature by means
After heating to a high temperature, the epoxy powder coating is electrostatically sprayed onto the surface of the deformed reinforcing bar after a predetermined time from the feed speed and the irregular shape to the surface soaking, which is determined by the irregular shape. A method for coating deformed reinforcing bars, characterized in that the roller is conveyed by flowing a small stream of cooling water at the contact point between the surface of the deformed reinforcing bar coated with paint and at least the surface of the coated reinforcing bar is water-cooled after the powder paint is cured. . 【請求項２】異形鉄筋を軸方向送りするローラ群，送り
通路に沿つて設けられた誘導加熱コイル，複数基の静電
噴射ガンおよび冷却ジヤケツトから構成され、上記誘導
加熱コイルと静電噴射ガンとの配置間隔を送り速度と異
形形状とから定まる所定間隔に設定し、上記複数基の静
電噴射ガンは送り通路の周方向に均等角度で分散配置さ
れるとともに、送り通路斜め後方から所定角度をもつて
送り通路の一点に照準を集中する如く設定され、当該静
電噴射ガンと上記冷却ジヤケツトとの配置間隔は少なく
とも異形鉄筋表面に付着した粉体塗料が硬化可能な時間
以上の送り時間経過距離とし、その間に間に配置されて
上方周面に接触する異形鉄筋を搬送可能な単数もしくは
複数の送り用ローラは冷却水ノズルを具えていて、当該
冷却水ノズルが送り方向後方側からた駆動ローラの上方
周接線沿いに冷却水の細流を噴流可能に設定されている
ことを特徴とする異形鉄筋の塗装装置。2. A group of rollers for axially feeding deformed reinforcing bars, an induction heating coil provided along a feed path, a plurality of electrostatic spray guns and a cooling jacket, the induction heating coil and the electrostatic spray gun. Is set to a predetermined interval determined by the feed speed and the irregular shape, and the plurality of electrostatic injection guns are distributed at equal angles in the circumferential direction of the feed passage and at a predetermined angle from the diagonal rear of the feed passage. Is set so as to concentrate the sighting on one point of the feed passage, and the arrangement interval between the electrostatic spray gun and the cooling jacket is at least the feed time longer than the time when the powder coating adhered to the surface of the deformed bar can be hardened. The distance is one or more, and one or a plurality of feed rollers, which are arranged between them and are capable of conveying deformed rebars that come into contact with the upper peripheral surface, are equipped with cooling water nozzles, and the cooling water nozzles feed the cooling water nozzles. Coating apparatus of the deformed bars, characterized in that the trickle of the cooling water is jet can be set along the upper circumferential tangent of the drive roller from the rearward side.