JPH09155240A - Liquid jetting device - Google Patents
Liquid jetting deviceInfo
- Publication number
- JPH09155240A JPH09155240A JP7348128A JP34812895A JPH09155240A JP H09155240 A JPH09155240 A JP H09155240A JP 7348128 A JP7348128 A JP 7348128A JP 34812895 A JP34812895 A JP 34812895A JP H09155240 A JPH09155240 A JP H09155240A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- nozzle
- valve
- chamber
- pressure sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Details Or Accessories Of Spraying Plant Or Apparatus (AREA)
- Nozzles (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】塗装用スプレーガンの使用時
において、ノズルの詰まりを検出すること、あるいはノ
ズルの摩耗を検出すること、あるいは均斉な厚みの塗膜
を形成すること等が、自動塗装ラインの製品を管理する
上においては極めて重要であり、本発明はこのような液
体噴射装置におけるノズルの詰まりの検出並びにノズル
の摩耗の検出のための装置に関するものである。BACKGROUND OF THE INVENTION When a spray gun for coating is used, it is possible to detect clogging of a nozzle, wear of a nozzle, or to form a coating film of uniform thickness. Is extremely important in managing the above products, and the present invention relates to a device for detecting nozzle clogging and nozzle wear in such a liquid ejecting apparatus.
【０００２】[0002]
【従来の技術】塗装用スプレーガンのような液体噴射装
置を塗装ロボットに適用して自動塗装ラインに使用する
場合には、使用中にノズルに詰まりが生じた場合あるい
は部分的に詰まりが生じた場合には、その詰まり現象を
検知して自動塗装ラインを停止すると共に、支障部分を
復元する必要があり、例えば図５のように、加圧塗料供
給源Ａから供給される加圧塗料を液体噴射装置における
本体Ｂの開閉弁Ｃの開閉のもとにノズルＤから適時的に
噴射するようにした液体噴射装置に対するノズルＤの詰
まりを検知する手段として、本体Ｂにおける塗料の入口
近くにノズルＤよりも流量が制限されるオリフィスＥを
設けると共に、このオリフィスＥの上流部分と下流部分
とに第１の圧力センサＦ１と第２の圧力センサＦ２とを
各別に設けて両圧力センサＦ１とＦ２との検出圧力を比
較し、その差圧の変化によりノズルＤの流量の変化を検
出するようにした先行技術（特開昭５８−１４６８２０
公報）がある。2. Description of the Related Art When a liquid jet device such as a spray gun for painting is applied to a painting robot and used in an automatic painting line, the nozzle is clogged or partially clogged during use. In this case, it is necessary to stop the automatic coating line by detecting the clogging phenomenon and restore the troubled part. For example, as shown in FIG. 5, the pressurized paint supplied from the pressurized paint supply source A is liquid. As a means for detecting clogging of the nozzle D with respect to the liquid ejecting device which ejects from the nozzle D at appropriate times under the opening and closing of the opening / closing valve C of the body B in the ejecting device, the nozzle D near the inlet of the paint in the body B The orifice E whose flow rate is restricted more than that of the orifice E is provided, and the first pressure sensor F1 and the second pressure sensor F2 are separately provided at the upstream portion and the downstream portion of the orifice E, so that both pressures are increased. Sensor F1 and compares the detected pressure of the F2, prior art so as to detect a change in the flow rate of the nozzle D by a change in the differential pressure (JP 58-146820
Gazette).
【０００３】また図６のように、液体噴射装置における
本体Ｂに設けた開閉弁ＣとノズルＤとの中間に圧力セン
サＦを設け、開閉弁Ｃの開通時の圧力測定により、ノズ
ルＤの流量の変化を検出するようにした先行技術（特開
昭６０−１２１５５公報）がある。Further, as shown in FIG. 6, a pressure sensor F is provided between the opening / closing valve C provided in the main body B of the liquid ejecting apparatus and the nozzle D, and the flow rate of the nozzle D is measured by measuring the pressure when the opening / closing valve C is opened. There is a prior art (Japanese Unexamined Patent Publication No. Sho 60-12155) that detects a change in the above.
【０００４】前記特開昭５８−１４６８２０公報に記載
の技術においては、オリフィスＥにおける流速がノズル
Ｄにおける流速に比較して約３倍になるようなオリフィ
スＥを選定する必要がある関係上、多数種のオリフィス
Ｅを用意してノズルＤの交換に伴いオリフィスＥを付け
換える必要があり、また圧力センサＦ１がノズルＤから
離隔した上流に設けられている関係上、応答性に乏し
く、かつ検出される電気的信号と吐出流量との関連性が
直接的でなく、供給塗料の設定圧力および還流圧力の脈
動の影響を受け易く、的確な圧力変動を検出するには満
足できるものではない。In the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 58-146820, a large number of orifices E are selected because it is necessary to select an orifice E in which the flow velocity in the orifice E is about three times that in the nozzle D. It is necessary to prepare a kind of orifice E and replace the orifice E with the replacement of the nozzle D. Also, since the pressure sensor F1 is provided upstream from the nozzle D, it has poor responsiveness and is detected. There is no direct relationship between the electric signal and the discharge flow rate, and the pressure is easily affected by the pulsation of the set pressure and the reflux pressure of the supplied paint, which is not satisfactory for detecting an accurate pressure fluctuation.
【０００５】特開昭６０−１２１５５公報に記載の技術
においては、１個の圧力センサＦの使用で足りる利点は
あるが、開閉弁ＣとノズルＤとの中間に圧力センサＦを
設けるのであるから、開閉弁ＣとノズルＤとの中間の流
路の容積は必然的に増加することになり、従って開閉弁
Ｃの閉止時に霧化されない液滴の飛散が生じるいわゆる
スピット現象が発生し易い欠陥がある。In the technique disclosed in Japanese Patent Laid-Open No. 60-12155, the use of one pressure sensor F is sufficient, but the pressure sensor F is provided between the on-off valve C and the nozzle D. However, the volume of the flow passage intermediate between the on-off valve C and the nozzle D will inevitably increase, so that there is a defect that a so-called spit phenomenon is likely to occur in which non-atomized droplets are scattered when the on-off valve C is closed. is there.
【０００６】そこで本発明の目的は、吐出量に即応した
圧力変動を検出して吐出量を的確に管理することができ
るようにすると同時に、スピット現象を防止し、均斉な
塗膜厚を容易に得ることができる液体噴射装置を提供す
ることにある。Therefore, an object of the present invention is to make it possible to accurately control the discharge amount by detecting the pressure fluctuation corresponding to the discharge amount, and at the same time prevent the spit phenomenon and facilitate the uniform coating film thickness. An object of the present invention is to provide a liquid ejecting apparatus that can be obtained.
【０００７】[0007]
【課題を解決するための手段】加圧液体供給源から供給
される加圧液体を装置本体の開閉弁の開閉のもとにノズ
ルから適時的に噴射するようにした液体噴射装置に対し
て、開閉弁に近い下流に流量制限用オリフィスを設け、
かつ開閉弁に近い上流に第１の圧力センサを設けるほ
か、オリフィスとノズルとの中間の流路にエゼクタを介
設すると共に、第２の圧力センサをその受圧面が前記エ
ゼクタの吸引部に連通するように設け、第１，第２両圧
力センサの検出圧力を比較してその差圧の変化によりノ
ズルの流量の変化を検出するようにしたことを特徴とす
るものである。A liquid ejecting apparatus in which a pressurized liquid supplied from a pressurized liquid supply source is ejected from a nozzle in a timely manner by opening and closing an opening / closing valve of an apparatus main body, A flow rate limiting orifice is provided downstream near the on-off valve,
Besides, a first pressure sensor is provided upstream near the on-off valve, an ejector is provided in an intermediate flow path between the orifice and the nozzle, and the second pressure sensor has a pressure receiving surface communicating with the suction portion of the ejector. It is characterized in that the change in the flow rate of the nozzle is detected by comparing the detected pressures of the first and second pressure sensors and the change in the differential pressure.
【０００８】上記解決手段によれば、開閉弁の閉止時に
おいては第１の圧力センサからは設定した液体供給圧力
に対応した検出電圧が出力され、第２の圧力センサから
は大気圧に基づく検出電圧が出力され、また開閉弁の開
通時においては、ノズルからの吐出に伴い第１の圧力セ
ンサからは設定した液体供給圧力よりも僅かに低下した
圧力に対応した検出電圧が出力され、第２の圧力センサ
からはオリフィスとノズルとの抵抗に関連して供給圧力
よりも低下した圧力に対応した検出電圧が出力され、こ
れら両検出電圧は比較回路により比較して電圧差として
出力される。According to the above solving means, when the on-off valve is closed, the first pressure sensor outputs the detection voltage corresponding to the set liquid supply pressure, and the second pressure sensor detects the atmospheric pressure based on the atmospheric pressure. When the on-off valve is opened, the first pressure sensor outputs a detection voltage corresponding to a pressure slightly lower than the set liquid supply pressure when the opening / closing valve is opened, and the second pressure sensor outputs the detected voltage. The pressure sensor outputs a detection voltage corresponding to the pressure lower than the supply pressure in relation to the resistance between the orifice and the nozzle, and these detection voltages are compared by a comparison circuit and output as a voltage difference.
【０００９】前記両圧力センサからの検出電圧の差電圧
の変化は、ノズルの吐出量の変化にほぼ正比例して得ら
れ、従って差電圧によりノズルからの吐出量が判明し、
これにより被着膜厚を管理することが可能であり、また
ノズルの摩耗の程度，ノズルの部分的な詰まり，ノズル
の完全な詰まり等が判明するのであって、ノズルにおけ
る吐出量が一定以上の変化を示す場合に、警報を発信あ
るいはラインの停止指示の発信を行うために利用するこ
とができる。The change in the difference voltage between the detection voltages from the two pressure sensors is obtained in almost direct proportion to the change in the discharge amount of the nozzle. Therefore, the difference voltage determines the discharge amount from the nozzle.
This makes it possible to control the film thickness of the deposited film, and to determine the degree of wear of the nozzle, partial clogging of the nozzle, complete clogging of the nozzle, etc. When a change is indicated, it can be used to issue an alarm or an instruction to stop the line.
【００１０】ノズルから液体を噴射している状態におい
ては、開閉弁とノズルとの流路の中間におけるエゼクタ
によりエゼクタの吸引室並びに吸引室に連通する流路以
外のスペースの圧力は流路よりも低圧に保たれ、これに
より噴射停止時において流路以外のスペースに貯溜され
ている液圧によるスピット発生要因を排除し、スピット
発生が防止される。When the liquid is jetted from the nozzle, the pressure in the suction chamber of the ejector and the space other than the flow passage communicating with the suction chamber by the ejector in the middle of the flow passage between the on-off valve and the nozzle is higher than that in the flow passage. The pressure is maintained at a low pressure, which eliminates the cause of spit generation due to the hydraulic pressure stored in the space other than the flow path when the injection is stopped, and prevents the generation of spit.
【００１１】[0011]
【発明の実施の形態】以下、本発明を図面の実施例につ
いて詳細に説明する。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments of the drawings.
【００１２】本発明の適用対象としての液体噴射装置と
しては、例えば図１のように、本体１の先端に取付部材
２を固設してこの取付部材２の先端にエアレス式の扇形
噴液ノズル３をホルダ４に嵌合したままリテーリングナ
ット５により固着すると共に、取付部材２の内方には弁
座６ａを固着し、これに対してガン本体１には弁座６ａ
に接離する針弁６ｂを弁室７において進退可能に設けた
まま、後方における駆動機構（図示せず）により適時的
に進退させることができるように設けて開閉弁６を構成
し、かつ弁室７には加圧液体供給源８から供給される加
圧塗料を圧力調整器９がある供給路１０により一定圧力
のもとに供給するようにするほか、絞り弁１１がある還
流路１２により加圧液体供給源８に戻すようにした型式
の噴霧塗装用の液体噴射装置を採択する。As a liquid ejecting apparatus to which the present invention is applied, for example, as shown in FIG. 1, an attachment member 2 is fixedly attached to the tip of a main body 1 and an airless fan-shaped jet liquid nozzle is attached to the tip of the attachment member 2. 3 is fixed to the holder 4 with the retaining nut 5, and a valve seat 6a is fixed to the inside of the mounting member 2, while the gun body 1 has a valve seat 6a.
The on-off valve 6 is configured so that the needle valve 6b that moves toward and away from the valve chamber 7 can be moved forward and backward in the valve chamber 7 by a drive mechanism (not shown) in the rear, and the on-off valve 6 is configured. In the chamber 7, the pressurized paint supplied from the pressurized liquid supply source 8 is supplied under a constant pressure by the supply passage 10 having the pressure regulator 9, and by the return passage 12 having the throttle valve 11. A liquid jet device for spray painting of a type adapted to return to the pressurized liquid supply source 8 is adopted.
【００１３】上記型式に対する本発明の特殊構成とし
て、図示の実施形態においては、前記弁室７に開閉弁６
になるべく近く受圧室１３を設けると共に、この受圧室
１３に受圧面１４ａが対向する状態のもとに圧電変換型
の第１の圧力センサ１４を設けて加圧塗料の供給圧力を
測定するようにし、また取付部材２には弁座６ａに近く
流量制限用オリフィス１５を設けると共に、このオリフ
ィス１５とノズル３との中間の流路に連通するように圧
電変換型の第２の圧力センサ１６を設けてノズル３から
吐出される直前の塗料の圧力を測定するようにし、これ
ら第１の圧力センサ１４による検出信号と第２の圧力セ
ンサ１６による検出信号とを比較回路１７により比較し
てそれら両信号の差によりノズル３からの吐出量を測定
するようにする。As a special configuration of the present invention with respect to the above type, in the illustrated embodiment, the opening / closing valve 6 is provided in the valve chamber 7.
A pressure receiving chamber 13 is provided as close as possible, and a piezoelectric conversion type first pressure sensor 14 is provided under the state where the pressure receiving surface 14a faces the pressure receiving chamber 13 to measure the supply pressure of the pressurized paint. Further, the mounting member 2 is provided with a flow rate limiting orifice 15 near the valve seat 6a, and a piezoelectric conversion type second pressure sensor 16 is provided so as to communicate with an intermediate flow passage between the orifice 15 and the nozzle 3. The pressure of the paint immediately before being ejected from the nozzle 3 is measured, and the detection signal from the first pressure sensor 14 and the detection signal from the second pressure sensor 16 are compared by the comparison circuit 17 and both signals are compared. The discharge amount from the nozzle 3 is measured by the difference of
【００１４】前記オリフィス１５とノズル３との中間の
流路にはエゼクタ１８を設けてその吸引室１９を前記第
２の圧力センサ１６の受圧面１６ａが露出する受圧室２
０に通孔２１により連通してなり、なおエゼクタ１８の
具体的構造としては、オリフィス１５がある第１部材２
２と、オリフィス１５の開口部を包囲する環状の前記吸
引室１９およびオリフィス１５がある第２部材２３と、
第２部材２３におけるオリフィス１５の開口部を包囲す
る環状の吸引室１９がある第３部材２４とを、上流から
順次共通軸線のもとに液密的に嵌合すると共に、受圧室
２０と第２部材２３の吸引室１９との間に前記通孔２１
を穿設して連通させる。An ejector 18 is provided in a flow passage intermediate between the orifice 15 and the nozzle 3, and the suction chamber 19 of the ejector 18 is exposed to the pressure receiving surface 16a of the second pressure sensor 16 and the pressure receiving chamber 2 is exposed.
The first member 2 having the orifice 15 is a specific structure of the ejector 18 that is in communication with 0 through the through hole 21.
2 and a second member 23 having an annular suction chamber 19 and an orifice 15 that surround the opening of the orifice 15,
The third member 24 having the annular suction chamber 19 surrounding the opening of the orifice 15 in the second member 23 is liquid-tightly fitted sequentially from the upstream under the common axis, and the pressure receiving chamber 20 and The through hole 21 is provided between the two member 23 and the suction chamber 19.
To make communication.
【００１５】前記受圧室２０および吸引室１９はこれら
の容積を可及的に小さくするのがよく、これがため第１
部材２２の先端部および第２部材２３の先端部をそれぞ
れ吸引室１９内に僅かなキャップ状間隙が形成されるよ
うに進入させるのがよい。It is preferable that the pressure receiving chamber 20 and the suction chamber 19 have their volumes as small as possible, which is why
It is preferable that the tip end of the member 22 and the tip end of the second member 23 enter the suction chamber 19 so as to form a slight cap-shaped gap.
【００１６】以上の構成のもとに、加圧液体供給源８か
ら供給される加圧塗料を圧力調整器９により一定圧力に
調整して供給路１０により弁室７に供給しつつ、絞り弁
１１がある還流路１２により加圧液体供給源８に戻すよ
うにし、弁室７の加圧塗料を常時一定の例えば４０ｋｇ
／ｃｍ２の圧力に保持しつつ、開閉弁６の開通により塗
料をノズル３から噴射するようにする。Based on the above construction, the pressure paint supplied from the pressurized liquid supply source 8 is adjusted to a constant pressure by the pressure adjuster 9 and is supplied to the valve chamber 7 through the supply passage 10, while the throttle valve is being supplied. 11 is returned to the pressurized liquid supply source 8 through the reflux path 12 and the pressure paint in the valve chamber 7 is kept constant at, for example, 40 kg.
The paint is jetted from the nozzle 3 by opening the on-off valve 6 while maintaining the pressure of / cm 2 .
【００１７】図３は開閉弁６の断続的な開通により得ら
れる第１の圧力センサ１４による検出信号と第２の圧力
センサ１６による検出信号とを表したグラフであって、
開閉弁６の閉止時においては第１の圧力センサ１４から
は設定した４０ｋｇ／ｃｍ２の圧力に対応した検出電圧
が出力され、第２の圧力センサ１６からは大気圧に基づ
く検出電圧が出力され、また開閉弁７の開通時において
は、ノズル３からの吐出に伴い第１の圧力センサ１４か
らは設定した４０ｋｇ／ｃｍ２よりも僅かに低下した圧
力に対応した検出電圧が出力され、第２の圧力センサ１
６からはオリフィス１５とノズル３との抵抗に関連して
供給圧力よりも低下した圧力に対応した検出電圧が出力
され、これら両検出電圧を次段の比較回路１７により電
圧差として出力する。FIG. 3 is a graph showing a detection signal by the first pressure sensor 14 and a detection signal by the second pressure sensor 16 obtained by intermittently opening the on-off valve 6.
When the on-off valve 6 is closed, the first pressure sensor 14 outputs the detection voltage corresponding to the set pressure of 40 kg / cm 2 , and the second pressure sensor 16 outputs the detection voltage based on the atmospheric pressure. When the on-off valve 7 is opened, the first pressure sensor 14 outputs a detection voltage corresponding to the pressure slightly lower than the set 40 kg / cm 2 in association with the discharge from the nozzle 3, and the second pressure sensor outputs the second detection voltage. Pressure sensor 1
A detection voltage corresponding to the pressure lower than the supply pressure is output from 6 in relation to the resistance between the orifice 15 and the nozzle 3, and both detection voltages are output as a voltage difference by the comparison circuit 17 in the next stage.
【００１８】前記両圧力センサ１４，１６からの検出電
圧の差電圧の変化は、ノズル３の吐出量の変化にほぼ正
比例し、図４のような結果が得られるのであって、即ち
第１部材２２におけるオリフィス１５の孔径が比較的小
径な場合の測定結果Ａにおいては、吐出量が７５〜２５
０ｃｃ／ｍｉｎの変化に対して１３０〜６４０ｍＶの変
化が良好な直線性のもとに得られ、また孔径が比較的大
径な場合の測定結果Ｂにおいては、吐出量が８５〜４５
５ｃｃ／ｍｉｎの変化に対して４５〜１６０ｍＶの変化
がほぼ良好な直線性のもとに得られ、オリフィス１５の
孔径の選定により的確な検出結果が得られるのであり、
ノズル３の流通断面積に対するオリフィス１５の流通断
面積の比率については、１〜５倍が最も好結果が得られ
るのであるが通常０．５〜６倍を実用範囲とし、なお数
〜数十倍であってもある程度の効果は認められるのであ
る。The change in the difference voltage between the detected voltages from the pressure sensors 14 and 16 is almost directly proportional to the change in the discharge amount of the nozzle 3, and the result as shown in FIG. 4 is obtained, that is, the first member. In the measurement result A when the hole diameter of the orifice 15 in No. 22 is relatively small, the discharge amount is 75 to 25
A change of 130 to 640 mV with respect to a change of 0 cc / min was obtained under good linearity, and in the measurement result B when the hole diameter was relatively large, the discharge amount was 85 to 45.
A change of 45 to 160 mV with respect to a change of 5 cc / min can be obtained with substantially good linearity, and an accurate detection result can be obtained by selecting the hole diameter of the orifice 15.
Regarding the ratio of the flow cross-sectional area of the orifice 15 to the flow cross-sectional area of the nozzle 3, 1 to 5 times gives the best result, but usually 0.5 to 6 times is the practical range, and several to several tens of times. Even so, some effect is recognized.
【００１９】前記比較回路１７から出力する信号によ
り、ノズル３からの吐出量が判明するから、これにより
塗装膜厚を必要最小限に管理することが可能であるほ
か、ノズル３の摩耗の程度，ノズル３の部分的な詰ま
り，ノズル３の完全な詰まり，塗料物性の異常発生等が
判明するのであって、ノズル３における吐出量が一定以
上の変化を示す場合に、警報を発信あるいは塗装ライン
の停止指示の発信を行うための警報装置あるいは必要な
制御装置を比較回路１７の後段に付設し、これによりノ
ズル３の交換等の復元作業を実施すればよい。Since the discharge amount from the nozzle 3 is known from the signal output from the comparison circuit 17, it is possible to control the coating film thickness to the necessary minimum, and the degree of wear of the nozzle 3 When it is found that the nozzle 3 is partially clogged, the nozzle 3 is completely clogged, the physical properties of the paint are abnormal, and the like, an alarm is issued or a coating line An alarm device for issuing a stop instruction or a necessary control device may be attached to the subsequent stage of the comparison circuit 17, so that the restoration work such as replacement of the nozzle 3 may be performed.
【００２０】ノズル３から塗料が吐出して前記エゼクタ
１８に塗料が通過する際に、吸引室１９はエゼクタ効果
により流過塗料の圧力よりも低圧となり、通孔２１およ
び受圧室２０の内部の圧力も低下し、同様に第２部材２
３と第３部材２４との両オリフィス１５の中間に塗料が
通過する際に吸引室１９はエゼクタ効果により流過塗料
の圧力よりも低圧となり、従って噴射停止時においては
開閉弁６とノズル３との間のスペースに貯溜されている
液圧によるスピット発生要因が排除される。When the paint is discharged from the nozzle 3 and passes through the ejector 18, the suction chamber 19 becomes a pressure lower than the pressure of the flow-through paint due to the ejector effect, and the pressure inside the through hole 21 and the pressure receiving chamber 20. Also decreases, and similarly the second member 2
3 and the third member 24, when the paint passes between the orifices 15 of the third member 24 and the third member 24, the suction chamber 19 becomes a pressure lower than the pressure of the flow-through paint due to the ejector effect. The factor that causes the spit due to the hydraulic pressure stored in the space between is eliminated.
【００２１】前記通孔２１同士を対応させるため、前記
エゼクタ１８の第２部材２３の外周には切欠溝２５を刻
設するほか、これに対して取付部材２には切欠溝２５に
対応する突起２６を設けてこの突起２６を切欠溝２５に
係合する。In order to make the through holes 21 correspond to each other, a cutout groove 25 is engraved on the outer periphery of the second member 23 of the ejector 18, while a projection corresponding to the cutout groove 25 is formed in the mounting member 2. 26 is provided, and the protrusion 26 is engaged with the cutout groove 25.
【００２２】以上のほか、受圧室２０内の空気を排出す
るため、並びにガン洗浄時に受圧室２０内の残留液を排
出するため、取付部材２には図２に示すように、受圧室
２０に開口するドレン孔２７を設けると共に、このドレ
ン孔２７に関連するドレン弁２８を付設して、必要に応
じドレン弁２８をねじ付ハンドル（図示せず）に対する
操作により進退させて開閉するようにするのが望まし
い。In addition to the above, in order to discharge the air in the pressure receiving chamber 20 and to discharge the residual liquid in the pressure receiving chamber 20 when cleaning the gun, the mounting member 2 is attached to the pressure receiving chamber 20 as shown in FIG. An open drain hole 27 is provided, and a drain valve 28 associated with the drain hole 27 is provided so that the drain valve 28 can be advanced and retracted and opened and closed by operating a screwed handle (not shown) as necessary. Is desirable.
【００２３】[0023]
【発明の効果】以上説明したように、本発明によれば、
次のような効果が得られる。As described above, according to the present invention,
The following effects can be obtained.
【００２３】ａ．開閉弁６に近い上流に加圧液体の供給
圧力を測定する第１の圧力センサ１４を設けるほか、開
閉弁６に近い下流には流量制限用オリフィス１５を設け
ると共に、このオリフィス１５とノズル３との中間にノ
ズル３から吐出される直前の液体の圧力を測定する第２
の圧力センサ１６を設け、更にこれら第１，第２両圧力
センサ１４，１６による検出信号を比較するようにした
から、これによりノズル３の吐出量の変化にほぼ正比例
した大きさの電気的変化として捕らえることができるば
かりでなく、液体の圧力をノズル３に近い部分において
検出する関係上、ノズル３の吐出量の変化を直接的かつ
安定的に測定することができ、ノズル３における種々の
変化を速い応答のもとに的確に把握して対処することが
できる。A. A first pressure sensor 14 for measuring the supply pressure of the pressurized liquid is provided upstream near the on-off valve 6, and a flow rate limiting orifice 15 is provided downstream near the on-off valve 6, and the orifice 15 and the nozzle 3 are provided. Second, the pressure of the liquid just before being discharged from the nozzle 3 is measured in the middle of
Since the pressure sensor 16 is provided and the detection signals from the first and second pressure sensors 14 and 16 are compared with each other, an electrical change having a magnitude substantially proportional to the change in the discharge amount of the nozzle 3 is thereby obtained. In addition, since the pressure of the liquid is detected in a portion close to the nozzle 3, the change in the discharge amount of the nozzle 3 can be directly and stably measured, and various changes in the nozzle 3 can be obtained. Can be grasped and dealt with accurately based on a quick response.
【００２４】ｂ．オリフィス１５の流通断面積をノズル
３のそれに対して０．５〜６倍に選定したことにより、
オリフィス１５における圧力損失を抑制してノズル３か
らの噴射速度を低下させることがないから、霧化効果を
損なわずに噴霧することができる。B. By selecting the flow cross-sectional area of the orifice 15 to be 0.5 to 6 times that of the nozzle 3,
Since the pressure loss in the orifice 15 is suppressed and the injection speed from the nozzle 3 is not reduced, the atomization can be performed without impairing the atomization effect.
【００２５】ｃ．開閉弁６に近い下流にオリフィス１５
と吸引室１９とがあるエゼクタ１８を設けると共に、こ
のエゼクタ１８の吸引室１９に連通する受圧室２０を設
け、受圧室２０に受圧面１６ａが露出する状態のもとに
第２の圧力センサ１６を設けたから、これにより開閉弁
６とノズル３との流路の中間に圧力センサ１６を設ける
にも拘らず、エゼクタ１８により噴射状態において開閉
弁６からノズル３までの流路以外のスペースの圧力を流
路よりも低圧に保ち、噴射停止時に貯溜液圧によるスピ
ット発生要因を排除し、スピット発生を防止することが
できる。C. Orifice 15 downstream near the on-off valve 6
And a suction chamber 19 are provided, a pressure receiving chamber 20 communicating with the suction chamber 19 of the ejector 18 is provided, and the second pressure sensor 16 is provided under the condition that the pressure receiving surface 16a is exposed in the pressure receiving chamber 20. Since the pressure sensor 16 is provided in the middle of the flow passage between the opening / closing valve 6 and the nozzle 3, the pressure of the space other than the flow passage from the opening / closing valve 6 to the nozzle 3 is ejected by the ejector 18 in the injection state. Can be kept at a lower pressure than the flow path, the cause of spit generation due to the stored liquid pressure when the injection is stopped can be eliminated, and the spit generation can be prevented.
【図１】本発明の液体噴射装置の要部を示す縦断側面図
である。FIG. 1 is a vertical sectional side view showing a main part of a liquid ejecting apparatus of the invention.
【図２】図１中の線ＩＩ−ＩＩにおける横断面図であ
る。FIG. 2 is a cross-sectional view taken along line II-II in FIG.
【図３】開閉弁の断続的な開通により得られる第１，第
２両圧力センサの検出信号のグラフである。FIG. 3 is a graph of detection signals of the first and second pressure sensors, which are obtained by intermittently opening and closing the on-off valve.
【図４】ノズルの吐出量と両圧力センサからの検出電圧
の差電圧との関係を示すグラフである。FIG. 4 is a graph showing a relationship between a discharge amount of a nozzle and a difference voltage between detection voltages from both pressure sensors.
【図５】従来装置の要部を示す縦断側面図である。FIG. 5 is a vertical sectional side view showing a main part of a conventional device.
【図６】他の従来装置の要部を示す縦断側面図である。FIG. 6 is a vertical cross-sectional side view showing a main part of another conventional device.
１ 本体 ３ ノズル ６ 開閉弁 ７ 弁室 ８ 加圧液体供給源 ９ 圧力調整器 １０ 供給路 １３ 受圧室 １４ 第１の圧力センサ １４ａ 受圧面 １５ オリフィス １６ 第２の圧力センサ １６ａ 受圧面 １７ 比較回路 １８ エゼクタ １９ 吸引室 ２０ 受圧室 1 Main Body 3 Nozzle 6 Open / Close Valve 7 Valve Chamber 8 Pressurized Liquid Supply Source 9 Pressure Regulator 10 Supply Channel 13 Pressure Receiving Chamber 14 First Pressure Sensor 14a Pressure Receiving Surface 15 Orifice 16 Second Pressure Sensor 16a Pressure Receiving Surface 17 Comparison Circuit 18 Ejector 19 Suction chamber 20 Pressure receiving chamber
Claims (2)
ると共に、ノズル（３）の上流には弁室（７）を形成し
てこれに開閉弁（６）を設け、弁室（７）には加圧液体
供給源（８）から供給される加圧液体を圧力調整器
（９）がある供給路（１０）により一定圧力のもとに供
給するようにするようにした型式の液体噴射装置であっ
て、前記開閉弁（６）に近い弁室（７）に受圧室（１
３）を設けると共に、この受圧室（１３）には受圧面
（１４ａ）が対向する状態のもとに加圧液体の供給圧力
を測定する第１の圧力センサ（１４）を設け、かつ開閉
弁（６）に近い下流には流量制限用オリフィス（１５）
と吸引室（１９）とがあるエゼクタ（１８）を設けると
共に、このエゼクタ（１８）の吸引室（１９）に連通す
る受圧室（２０）を設け、受圧室（２０）に受圧面（１
６ａ）が露出する状態のもとにノズル（３）から吐出さ
れる直前の液体の圧力を測定する第２の圧力センサ（１
６）を設け、更にこれら第１の圧力センサ（１４）によ
る検出信号と第２の圧力センサ（１６）による検出信号
とを比較して両信号の差を出力する比較回路（１７）を
設けたことを特徴とする液体噴射装置。1. A nozzle (3) is provided at the tip of a main body (1), and a valve chamber (7) is formed upstream of the nozzle (3) and an opening / closing valve (6) is provided in the valve chamber (7). 7) is a type in which the pressurized liquid supplied from the pressurized liquid supply source (8) is supplied under a constant pressure through the supply passage (10) having the pressure regulator (9). In the liquid ejecting apparatus, a pressure chamber (1) is provided in a valve chamber (7) near the on-off valve (6).
3) is provided, and the pressure receiving chamber (13) is provided with a first pressure sensor (14) for measuring the supply pressure of the pressurized liquid under the state where the pressure receiving surface (14a) faces the open / close valve. A flow rate limiting orifice (15) is provided downstream near (6).
An ejector (18) including a suction chamber (19) and a suction chamber (19) is provided, a pressure receiving chamber (20) communicating with the suction chamber (19) of the ejector (18) is provided, and the pressure receiving surface (1) is provided in the pressure receiving chamber (20).
The second pressure sensor (1) for measuring the pressure of the liquid immediately before being ejected from the nozzle (3) under the condition that 6a) is exposed.
6) is provided, and further a comparison circuit (17) is provided for comparing the detection signal from the first pressure sensor (14) with the detection signal from the second pressure sensor (16) and outputting the difference between the two signals. A liquid ejecting apparatus characterized by the above.
ル（３）の流通断面積に対して０．５ないし６倍に選定
した請求項１の液体噴射装置。2. The liquid ejecting apparatus according to claim 1, wherein the flow cross-sectional area of the orifice (15) is selected to be 0.5 to 6 times the flow cross-sectional area of the nozzle (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7348128A JPH09155240A (en) | 1995-12-07 | 1995-12-07 | Liquid jetting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7348128A JPH09155240A (en) | 1995-12-07 | 1995-12-07 | Liquid jetting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09155240A true JPH09155240A (en) | 1997-06-17 |
Family
ID=18394941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7348128A Pending JPH09155240A (en) | 1995-12-07 | 1995-12-07 | Liquid jetting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09155240A (en) |
-
1995
- 1995-12-07 JP JP7348128A patent/JPH09155240A/en active Pending
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