JP5921185B2 - Swing check valve - Google Patents
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Description
本発明は、流路を流れる流体の逆流を防止し、流体を一方向のみに流すスイング式逆止弁に関する。 The present invention relates to a swing type check valve that prevents a reverse flow of a fluid flowing through a flow path and allows the fluid to flow in only one direction.
従来より、ＬＮＧプラントや化学プラント等において、各種流体の輸送用配管の途中部に配置され、輸送用配管内を流れる流体流量が多いとき、弁座から離隔して開弁し、流体の流れが少量又は止められたとき、自重により弁座に当接して閉弁する弁体を備えたスイング式逆止弁が知られている。 Conventionally, in a LNG plant, a chemical plant, etc., when the flow rate of fluid flowing through the transportation pipe is large, it is opened away from the valve seat, and the fluid flows. 2. Description of the Related Art A swing type check valve having a valve body that closes against a valve seat by its own weight when stopped by a small amount is known.
このスイング式逆止弁５１は、図４に一例を示すように、入口部５３ａから出口部５３ｂへ延びる流路５３が形成された弁ケース５２と、流路５３の途中部に設けられた弁座５４と、この弁座５４上側に設けられた回動軸５６を中心にスイング可能なアーム５５と、このアーム５５先端に取付けられた弁体５７と、この弁体５７の外周部分に弁座５４に当接する弁部５７ａとを備え、流路５３内を流れる流体流量が多いとき、弁部５７ａが弁座５４から離隔して開弁し、流体の流れが止まったとき、弁体５７の自重により弁部５７ａが弁座５４に当接して閉弁するように構成されている。 As shown in FIG. 4, the swing type check valve 51 includes a valve case 52 in which a flow path 53 extending from the inlet 53 a to the outlet 53 b is formed, and a valve provided in the middle of the flow path 53. A seat 54, an arm 55 swinging around a rotation shaft 56 provided above the valve seat 54, a valve body 57 attached to the tip of the arm 55, and a valve seat on the outer periphery of the valve body 57 When the flow rate of fluid flowing through the flow path 53 is large, the valve portion 57a is opened away from the valve seat 54, and when the flow of fluid stops, The valve portion 57a contacts the valve seat 54 and closes by its own weight.
このようなスイング式逆止弁では、入口側の流体が吹き出し圧力（セット圧力ともいう）を僅かに超えた状態で一定流量に安定したとき、弁体５７が数１０Ｈｚ以下の比較的低周波の振動を繰り返し、この振動に伴う往復運動により弁部５７ａが弁座５４を周期的に打撃する現象、所謂チャタリングを生じることがある。このチャタリングが発生した場合、弁体５７と弁座５４の打撃による損傷や、これに起因して弁座５４からの漏洩や打撃部分の摩耗及び配管振動等を引き起こす虞がある。 In such a swing type check valve, when the fluid on the inlet side is stabilized at a constant flow rate slightly exceeding the blowing pressure (also referred to as set pressure), the valve body 57 has a relatively low frequency of several tens Hz or less. A phenomenon in which the valve portion 57a periodically hits the valve seat 54, that is, chattering, may occur due to repeated vibrations and reciprocating motion accompanying the vibrations. When this chattering occurs, there is a risk of damage caused by striking the valve element 57 and the valve seat 54, leakage from the valve seat 54, wear of the striking portion, piping vibration, and the like.
弁体と弁座に係るチャタリング発生のメカニズムは、以下のように考えられている。
（ｉ）弁体上流側の流体圧が吹き出し圧力を僅かに超えた状態で一定流量に安定した、所謂チャタリング発生域のとき、流体から弁体に加わる揚弁力（開弁力）が弁体を押し上げ、弁体が弁座から微小距離離隔して開弁状態になる。
（ii）弁体上流側の流体速度が増加し、流体の運動量と圧力損出が増すことにより、弁体上流側の流体圧が減少する。
（iii）弁体上流側の流体圧が吹き止まり圧力を下回り、弁部が弁座に当接して閉弁状態になる。
（iv）弁体上流側の流体速度が低下し、流体の運動量と圧力損出が減少することにより、弁体上流側の流体圧が増加する。
（ｖ）前記（ｉ）〜（iv）を繰り返す。
The mechanism of chattering generation relating to the valve body and the valve seat is considered as follows.
(I) When the fluid pressure on the upstream side of the valve body is in a so-called chattering region where the fluid pressure is slightly higher than the discharge pressure and is stable, the valve lift force (opening force) applied from the fluid to the valve body is Is pushed up, and the valve body is separated from the valve seat by a minute distance to open the valve.
(Ii) The fluid velocity on the upstream side of the valve body is increased, and the fluid momentum on the upstream side of the valve body is decreased by increasing the momentum and pressure loss of the fluid.
(Iii) The fluid pressure on the upstream side of the valve body stops blowing and falls below the pressure, and the valve portion comes into contact with the valve seat to be closed.
(Iv) The fluid velocity on the upstream side of the valve body is decreased, and the fluid momentum on the upstream side of the valve body is increased by decreasing the momentum and pressure loss of the fluid.
(V) Repeat (i) to (iv) above.
前述したチャタリングの発生を回避するための対策として、
（１）弁体上流側の流体の圧力変化を吹き出し圧力と吹き止まり圧力との差（吹下り圧力）よりも小さくする、
（２）流路を流れる流体流量を多くする（揚弁力を大きくする）、
（３）弁体の重量を軽くして吹き出し圧力を低下する、
等が知られている。
前記（１）は、配管長等の設備側の要求や流体の流路抵抗等の要因によって決定されるものであり、弁体上流側の流体の圧力変化を調整することは容易ではない。前記（２）についても、流体の受入側の要求によって決定されるものであり、チャタリング防止のために流体を増量することは前記（１）と同様の問題がある。
As a measure to avoid the chattering mentioned above,
(1) The pressure change of the fluid upstream of the valve body is made smaller than the difference between the blowing pressure and the blow-off pressure (blowing pressure).
(2) Increase the flow rate of fluid flowing through the flow path (increase the valve lift force),
(3) Reduce the blowing pressure by reducing the weight of the valve body,
Etc. are known.
Said (1) is determined by factors such as pipe length and other requirements on the equipment side, fluid flow path resistance, etc., and it is not easy to adjust the pressure change of the fluid upstream of the valve element. The above (2) is also determined by the demand on the fluid receiving side, and increasing the amount of fluid to prevent chattering has the same problem as the above (1).
前記（３）では、吹き出し圧力を低下して、チャタリング発生域を吹き出し圧力に応じて低圧側に移動でき、これに伴い発生頻度自体も減少させることができる。
しかし、このような逆止弁では、流体逆流時の流体圧に耐え得る強度が要求されるため、要求される強度に応じた厚さが必要であり、その重量も大きくなる。それ故、逆止弁機能との関係上、弁体の軽量化には限界がある。
In (3), the blowing pressure can be lowered, the chattering generation area can be moved to the low pressure side according to the blowing pressure, and the occurrence frequency itself can be reduced accordingly.
However, such a check valve is required to have a strength that can withstand the fluid pressure at the time of fluid backflow, and thus requires a thickness corresponding to the required strength, and its weight also increases. Therefore, there is a limit to the weight reduction of the valve body in relation to the check valve function.
特許文献１のスイング式逆止弁は、流路が形成された弁ケースと、流路の途中部に設けられた弁座と、この弁座の上側に設けられた回動軸を中心にスイング可能なアームと、このアーム先端に取付けられた弁体と、この弁体の外周部分に弁座に当接する弁部と、弁体が全開状態のとき弁体と当接するストッパと、回動軸回りに設けられたねじりコイルばねとを備え、ねじりコイルばねが開弁状態から全開状態に至るまでの間、弁体を閉弁側へ付勢するように構成されている。このスイング式逆止弁では、開弁状態のとき、弁体を閉弁側に付勢して弁体と受け座に相当するストッパとの当接頻度を抑制することにより、ストッパ側チャタリング発生域におけるチャタリングの発生防止を図っている。 The swing type check valve disclosed in Patent Document 1 swings around a valve case in which a flow path is formed, a valve seat provided in the middle of the flow path, and a rotation shaft provided above the valve seat. A possible arm, a valve body attached to the tip of the arm, a valve portion that comes into contact with the valve seat on the outer peripheral portion of the valve body, a stopper that comes into contact with the valve body when the valve body is fully opened, and a pivot shaft And a torsion coil spring provided around, and is configured to urge the valve body toward the valve closing side until the torsion coil spring reaches the fully open state from the valve open state. In this swing type check valve, when the valve is open, the valve body is urged toward the valve closing side to suppress the contact frequency between the valve body and the stopper corresponding to the receiving seat, thereby preventing the chattering occurrence region on the stopper side. To prevent chattering.
また、弁体に、小流量の流体を流通可能な小孔部を形成し、弁体の出口側面部に、自重で小孔部に接することにより小孔部を塞ぎ且つ小孔部を通る流体により押し上げられて小孔部を開く小弁体を設けたスイング式逆止弁も公知である。このスイング式逆止弁では、チャタリング発生域において、弁体の開弁を伴うことなく小弁体が開閉するため、弁体のチャタリングの発生を回避できる。 Further, a small hole portion through which a small amount of fluid can flow is formed in the valve body, and the small hole portion is closed by contacting the small hole portion by its own weight on the outlet side surface portion of the valve body, and the fluid passes through the small hole portion. There is also known a swing type check valve provided with a small valve body that is pushed up by the valve to open a small hole. In this swing type check valve, since the small valve body opens and closes without opening the valve body in the chattering generation region, the occurrence of chattering of the valve body can be avoided.
特許文献１のスイング式逆止弁は、開弁状態から弁体とストッパとが当接する全開状態への回動を抑制しているため、配管長等の設備側の要求に拘わらずストッパ側チャタリング発生域におけるチャタリング発生を回避することができる。しかし、特許文献１の技術を弁座側に発生するチャタリング対策に適用した場合、次のような課題が生じる。
即ち、開弁状態から閉弁状態に至るまでの間では、弁体を開弁側へ付勢するねじりコイルばねを設けた場合、チャタリング発生域における開弁状態の弁体と弁座との当接頻度を抑制することはできる。しかし、閉弁状態であっても弁体が開弁側へ付勢されているため、本来は開動作しない程度の弁体上流側の流体圧であっても、弁体が開弁し、結果的に弁体と弁座との当接頻度を抑制できずチャタリングの発生を招く虞がある。
Since the swing type check valve of Patent Document 1 suppresses the rotation from the opened state to the fully opened state where the valve body and the stopper come into contact with each other, the chattering on the stopper side is performed regardless of the requirements on the equipment side such as the pipe length. Chattering in the generation area can be avoided. However, when the technique of Patent Document 1 is applied to a chattering countermeasure that occurs on the valve seat side, the following problems arise.
In other words, during the period from the valve opening state to the valve closing state, when a torsion coil spring is provided to bias the valve body toward the valve opening side, the contact between the valve body in the chattering occurrence region and the valve seat The contact frequency can be suppressed. However, even when the valve is closed, the valve element is biased toward the valve opening side, so even if the fluid pressure is upstream of the valve element so that it does not normally open, the valve element opens. In particular, the contact frequency between the valve body and the valve seat cannot be suppressed, and chattering may occur.
また、チャタリング発生域において小孔部を開く小弁体を備えたスイング式逆止弁では、弁体と弁座との当接頻度を抑制できるものの、依然として小弁体のチャタリングが発生する。しかも、小弁体が水平よりも上向きに押し上げられた状態から急激に流体が逆流したとき、流体が小弁体を押し上げる方向に流れるため、小孔部の開状態が継続し、逆止弁機能が阻害される虞もある。 Further, in the swing type check valve provided with the small valve body that opens the small hole portion in the chattering generation region, the contact frequency between the valve body and the valve seat can be suppressed, but the chattering of the small valve body still occurs. In addition, when the fluid suddenly flows backward from the state where the small valve body is pushed upward from the horizontal, the fluid flows in the direction pushing up the small valve body, so the small hole portion continues to open, and the check valve function May be disturbed.
本発明の目的は、逆止弁機能の向上とチャタリング防止とを両立することができるスイング式逆止弁を提供することである。 An object of the present invention is to provide a swing type check valve capable of achieving both improvement of the check valve function and prevention of chattering.
請求項１のスイング式逆止弁は、入口部から出口部へ延びる流路が形成された弁ケースと、前記流路の途中部に設けられた弁座と、この弁座の上側に設けられた回動軸を中心にスイング可能なアームと、このアーム先端に取付けられた弁体とを備え、前記弁体が自重により閉弁するスイング式逆止弁において、前記弁体の外周部分に前記弁座に当接する弁部を形成すると共に、前記弁体に前記弁部の少なくとも一部から弁体の径方向外側へ張り出した拡張部を設け、前記拡張部の軸心方向の厚さが弁部の軸心方向の厚さよりも小さく形成され、前記拡張部は、前記弁体が閉弁状態のとき前記弁座の外周側の壁部から前記流路を流れる流体の流れ方向の下流側へ離隔するように形成されたことを特徴としている。 The swing type check valve according to the first aspect is provided with a valve case in which a flow path extending from an inlet portion to an outlet portion is formed, a valve seat provided in a middle portion of the flow passage, and an upper side of the valve seat. A swing type check valve in which the valve body is closed by its own weight, and an outer peripheral portion of the valve body includes the arm that can swing around the rotating shaft and a valve body attached to the tip of the arm. to form a contact with the valve portion in the valve seat, at least a part provided an extension which projects radially outward of the valve body from the thickness in the axial direction of the expansion portion is a valve of the valve unit to the valve body The extension portion is formed downstream from the wall portion on the outer peripheral side of the valve seat in the flow direction of the fluid flowing through the flow path when the valve body is in a closed state. It is characterized by being formed to be separated .
請求項１の発明によれば、弁部の少なくとも一部から弁体の径方向外側へ張り出した拡張部を設けたことにより、開弁状態における流体を受ける弁体の受圧面積を閉弁状態における流体を受ける弁体の受圧面積よりも増加することができるため、開弁により弁体上流側の流体圧が減少しても、弁体に作用する揚弁力の低下を抑制でき、弁体と弁座との当接頻度を抑制してずチャタリングの発生を回避することができる。しかも、開弁状態において急激に流体が逆流したとき、弁体下流側の流体に対する受圧面積が大きく、弁体を閉弁方向に回動するための閉弁力を大きくすることができるため、閉弁動作の応答性を高くでき、逆止弁機能を向上することができる。 According to the first aspect of the present invention, by providing the expansion portion that protrudes from the at least part of the valve portion to the radially outer side of the valve body, the pressure receiving area of the valve body that receives the fluid in the valve open state is set in the valve closed state. Since the pressure receiving area of the valve body that receives the fluid can be increased, even if the fluid pressure on the upstream side of the valve body decreases due to the valve opening, it is possible to suppress a decrease in the lift force that acts on the valve body. The occurrence of chattering can be avoided without suppressing the contact frequency with the valve seat. Moreover, when the fluid suddenly flows back in the valve open state, the pressure receiving area for the fluid downstream of the valve body is large, and the valve closing force for rotating the valve body in the valve closing direction can be increased. The responsiveness of the valve operation can be increased, and the check valve function can be improved.
そして、閉弁状態のとき、拡張部が弁座の外周側の壁部と当接しないため、拡張部の軸心方向の厚さを小さくすることができ、弁体の軽量化によりチャタリングの発生を一層防止することができる。 And when the valve is closed, the extension part does not contact the outer wall of the valve seat, so the thickness of the extension part in the axial direction can be reduced, and chattering can be generated by reducing the weight of the valve body. Can be further prevented.
以下、本発明の実施の形態について実施例に基づいて説明する。 Hereinafter, embodiments of the present invention will be described based on examples.
実施例１について、図１〜３に基づいて説明する
本実施例のスイング式逆止弁１は、流体を流すための流路３が形成された弁ケース２と、流路３の途中部に設けられた弁座４と、回動軸６を中心にスイング可能なアーム５と、このアーム５先端に取付けられた弁体７とを備え、この弁体７が自重により閉弁可能に構成されることにより流体を一方向のみに流す逆止弁である。
Embodiment 1 will be described with reference to FIGS. 1 to 3. The swing type check valve 1 of this embodiment includes a valve case 2 in which a flow path 3 for flowing a fluid is formed and a middle portion of the flow path 3. A valve seat 4 provided, an arm 5 that can swing around a rotating shaft 6, and a valve body 7 that is attached to the tip of the arm 5 are provided. The valve body 7 can be closed by its own weight. This is a check valve that allows fluid to flow only in one direction.
図１，図２に示すように、弁ケース２は、流体（例えば、天然ガス等）の輸送用配管（図示略）の途中部に接続され、入口部３ａと、出口部３ｂと、作業部３ｃの３つの開口を備えた金属製ケーシングで構成されている。弁ケース２の内部には、入口部３ａから出口部３ｂに亙って直線状に延びる流路３と、ストッパ８とが形成されている。
このストッパ８は、流路３を流れる流体流量が増加し、弁体７が全開状態のとき、弁体７の下流側背面部と当接して弁体７の開度を一定に保持している。
As shown in FIGS. 1 and 2, the valve case 2 is connected to a middle part of a transportation pipe (not shown) for fluid (for example, natural gas), and includes an inlet part 3 a, an outlet part 3 b, and a working part. It is comprised by the metal casing provided with three openings of 3c. Inside the valve case 2, a flow path 3 extending linearly from the inlet 3a to the outlet 3b and a stopper 8 are formed.
When the flow rate of the fluid flowing through the flow path 3 is increased and the valve body 7 is in a fully open state, the stopper 8 contacts the downstream side rear surface portion of the valve body 7 to keep the opening degree of the valve body 7 constant. .
入口部３ａは、流体を加圧するコンプレッサ（図示略）に連なる上流側配管（図示略）とフランジ２ａを介して接続され、出口部３ｂは、受け側設備と連なる下流側配管（図示略）とフランジ２ｂを介して接続される。作業部３ｃは、フランジ２ｃに複数のボルト１０により固定された円盤状蓋部材９によって閉鎖され、弁体７の組付けやメインテナンスのとき、蓋部材９をフランジ２ｃから取り外して所定の作業を行う。 The inlet 3a is connected to an upstream pipe (not shown) connected to a compressor (not shown) for pressurizing fluid via a flange 2a, and the outlet 3b is connected to a downstream pipe (not shown) connected to a receiving facility. It is connected via the flange 2b. The working portion 3c is closed by a disc-like lid member 9 fixed to the flange 2c with a plurality of bolts 10. When the valve body 7 is assembled or maintained, the lid member 9 is removed from the flange 2c to perform a predetermined work. .
図１に示すように、環状の弁座４は、流路３の入口部３ａ側途中部に形成された壁部２ｄの径方向内側部分において流体の流れ方向下流側へ突出するように形成されている。
尚、以下、流体の流れ方向における上下流側を上下流側として説明する。
As shown in FIG. 1, the annular valve seat 4 is formed so as to protrude downstream in the fluid flow direction at a radially inner portion of the wall 2 d formed in the middle of the flow path 3 on the inlet 3 a side. ing.
Hereinafter, the upstream and downstream sides in the fluid flow direction will be described as upstream and downstream.
アーム５は、略Ｌ字状に形成され、一端に回動軸６へ外装可能な回動部５ａを備え、他端に筒状の弁体支持部５ｂを備えている。回動軸６は、壁部２ｄにおいてフランジ２ｃと弁座４の上端との略中間位置に設けられ、回動部５ａを回動自在に枢支している。この回動軸６は、図２に示すように、弁ケース２に設けられた挿通穴に挿通され、その基端部分に内嵌されたブッシュ１１を介してプラグ１２によって抜け止めされている。 The arm 5 is formed in a substantially L shape, and includes a rotating portion 5a that can be mounted on the rotating shaft 6 at one end, and a cylindrical valve body support portion 5b at the other end. The rotation shaft 6 is provided at a substantially intermediate position between the flange 2c and the upper end of the valve seat 4 in the wall portion 2d, and pivotally supports the rotation portion 5a. As shown in FIG. 2, the rotating shaft 6 is inserted into an insertion hole provided in the valve case 2, and is prevented from being detached by a plug 12 through a bush 11 fitted in a base end portion thereof.
図１に示すように、弁体７は、ステンレス鋼（例えば、ＳＵＳ３１６）により円板状に形成され、弁座４と当接可能な弁部７ａと、弁体７を弁体支持部５ｂに固定するための軸部７ｂと、凹部７ｃと、環状の拡張部１３とが同心状に一体形成されている。
この弁体７は、流路３内を流れる流体流量が多いとき、弁部７ａが弁座４から下流側へ離隔して開弁し、流体の流れが止まったとき、弁体７の自重により弁部７ａが弁座４に当接して閉弁するように構成されている。
As shown in FIG. 1, the valve body 7 is formed in a disc shape from stainless steel (for example, SUS316), and a valve portion 7 a that can contact the valve seat 4, and the valve body 7 as a valve body support portion 5 b. A shaft portion 7b for fixing, a concave portion 7c, and an annular extension portion 13 are integrally formed concentrically .
When the flow rate of the fluid flowing through the flow path 3 is large, the valve body 7 is opened by separating the valve portion 7a from the valve seat 4 to the downstream side. When the flow of the fluid stops, the valve body 7 is caused by its own weight. The valve portion 7a is configured to abut against the valve seat 4 and close.
弁部７ａは、閉弁状態の弁体７の外周部分において上流側へ突出するように形成され、弁部７ａの上流側端面が弁座４の下流側端面と面接触するように環状に構成されている。軸部７ｂは、閉弁状態の弁体７の中央部分から下流側へ延びるように形成され、下流端部分には雄ねじが形成されている。この軸部７ｂは、弁体支持部５ｂに上流側から挿通され、雄ねじに螺合可能なナット１５によって弁体支持部５ｂに固定される。
凹部７ｃは、閉弁状態の弁体７の上流側部分に凹入形成され、凹部７ｃの軸心方向の厚さが、弁部７ａの軸心方向の厚さよりも小さく設定されている。
The valve portion 7a is formed so as to protrude upstream in the outer peripheral portion of the valve body 7 in the closed state, and is configured to be annular so that the upstream end surface of the valve portion 7a is in surface contact with the downstream end surface of the valve seat 4 Has been. The shaft portion 7b is formed so as to extend downstream from the central portion of the valve body 7 in the valve-closed state, and a male screw is formed at the downstream end portion. The shaft portion 7b is inserted into the valve body support portion 5b from the upstream side, and is fixed to the valve body support portion 5b by a nut 15 that can be screwed to the male screw.
The recessed portion 7c is recessedly formed in the upstream side portion of the valve body 7 in the closed state, and the axial thickness of the recessed portion 7c is set smaller than the axial thickness of the valve portion 7a.
図１に示すように、拡張部１３は、閉弁状態の弁部７ａの下流端全周から弁体７の径方向外側へ環状に張り出し、その軸心方向の厚さが、弁部７ａの軸心方向の厚さ、更には、凹部７ｃの軸心方向の厚さよりも小さく形成されている。それ故、拡張部１３は、弁体７が閉弁状態のとき弁座４の外周側の壁部２ｄから下流側へ離隔して配置されている。 As shown in FIG. 1, the expanded portion 13 projects annularly from the entire downstream end of the valve portion 7a in the valve-closed state to the radially outer side of the valve body 7, and the thickness in the axial direction of the valve portion 7a The thickness in the axial direction is further smaller than the thickness in the axial direction of the recess 7c. Therefore, the expansion part 13 is arranged to be separated from the wall part 2d on the outer peripheral side of the valve seat 4 to the downstream side when the valve body 7 is in the closed state.
次に、スイング式逆止弁１の作用・効果について説明する。
図３（ａ）に示すように、流路３内の流体の流速が略零の閉弁状態のとき、弁体７の揚弁力（弁体７が流体から受ける力）Ｆｗａは、次式（１）のように表すことができる。
Ｆｗａ＝π（ｒａ）２×△Ｐ …（１）
ｒａは弁部７ａ（内周端）の半径、△Ｐは配管内の流体圧変化に起因する一次圧と二次圧との差圧である。尚、説明の便宜上、弁体７に作用する圧力分布の項を省略し、流体の動圧が弁体７に一律に作用する簡易モデルにより説明する。
Next, the operation and effect of the swing check valve 1 will be described.
As shown in FIG. 3A, when the fluid flow rate in the flow path 3 is in a closed state where the flow velocity is substantially zero, the valve lift force of the valve body 7 (the force that the valve body 7 receives from the fluid) Fwa is It can be expressed as (1).
Fwa = π (ra) 2 × ΔP (1)
ra is a radius of the valve portion 7a (inner peripheral end), and ΔP is a differential pressure between the primary pressure and the secondary pressure caused by a change in fluid pressure in the pipe. For convenience of explanation, the term of the pressure distribution acting on the valve body 7 is omitted, and a simple model in which the fluid dynamic pressure acts uniformly on the valve body 7 will be described.
図３（ｂ），図３（ｃ）に示すように、弁部７ａが弁座４から下流側へ離隔した開弁状態直後のとき、弁体７の揚弁力Ｆｗｂは、次式（２）のように表すことができる。
Ｆｗｂ＝（１／２）×ρ×π（ｒｂ）２×ｃｏｓθ×（Ｖｂ）２×Ｃｘ …（２）
ρは流体密度、ｒｂ（ｒａ＜ｒｂ）は拡張部１３を含む弁体７の半径、θは鉛直方向に対する弁体７の傾き、Ｃｘは抵抗係数、Ｖｂは流速であり、この流速Ｖｂは傾きθに依存する。
As shown in FIGS. 3B and 3C, when the valve portion 7a is immediately after the valve opening state separated from the valve seat 4 to the downstream side, the valve lift force Fwb of the valve body 7 is expressed by the following equation (2) ).
Fwb = (1/2) × ρ × π (rb) 2 × cos θ × (Vb) 2 × Cx (2)
ρ is the fluid density, rb (ra <rb) is the radius of the valve body 7 including the expanded portion 13, θ is the inclination of the valve body 7 with respect to the vertical direction, Cx is the resistance coefficient, Vb is the flow velocity, and this flow velocity Vb is the gradient. Depends on θ.
ここで、次式（３）に示す閉弁モーメントＭｃが次式（４）に示す開弁モーメントＭｏよりも大きいとき、チャタリングが発生する。
Ｍｃ＝Ｍ×ｇ×ｓｉｎθ×Ｌ …（３）
Ｍはアーム５と弁体７の合計重量、ｇは重力加速度、Ｌは回動軸６からアーム５と弁体７との重心Ｇまでの距離である。
Ｍｏ＝Ｆｗｂ×Ｌ …（４）
そこで、スイング式逆止弁１の弁体７では、所定の低流量でも開弁モーメントＭｏが閉弁モーメントＭｃよりも大きくなるように、Ｍを抑え、ｒｂ（拡張部１３の面積）を大きくなるように設定している。
Here, when the valve closing moment Mc shown in the following equation (3) is larger than the valve opening moment Mo shown in the following equation (4), chattering occurs.
Mc = M × g × sin θ × L (3)
M is the total weight of the arm 5 and the valve body 7, g is the gravitational acceleration, and L is the distance from the pivot shaft 6 to the center of gravity G of the arm 5 and the valve body 7.
Mo = Fwb × L (4)
Therefore, in the valve element 7 of the swing type check valve 1, M is suppressed and rb (the area of the expansion portion 13) is increased so that the valve opening moment Mo is larger than the valve closing moment Mc even at a predetermined low flow rate. It is set as follows.
以上のように、スイング式逆止弁１では、弁体７の重量増加を抑制しつつ、開弁状態の弁体７の受圧面積π（ｒｂ）２を、閉弁状態の弁体７の受圧面積π（ｒａ）２よりも拡大することができる。即ち、開弁状態の流体流量が同じ従来型の弁体（半径がｒａ）と弁体７とを比較したとき、弁体７の受圧面積π（ｒｂ）２を従来型の弁体の受圧面積π（ｒａ）２よりも大きくすることができ、これに伴い揚弁力も大きくできるから、弁体７上流側の流体圧変化が生じた場合でも、従来型の弁体と比べて開弁モーメントＭｏを閉弁モーメントＭｃよりも大きな状態に維持することができる。 As described above, in the swing type check valve 1, the pressure receiving area π (rb) 2 of the valve body 7 in the valve opening state is set to the pressure receiving pressure of the valve body 7 in the valve closing state while suppressing an increase in the weight of the valve body 7. The area can be larger than π (ra) 2 . That is, when the conventional valve body (radius is ra) and the valve body 7 with the same fluid flow rate in the valve open state are compared, the pressure receiving area π (rb) 2 of the valve body 7 is the pressure receiving area of the conventional valve body. Since it can be larger than π (ra) 2 and the valve lift force can be increased accordingly, even when a fluid pressure change on the upstream side of the valve body 7 occurs, the valve opening moment Mo is larger than that of the conventional valve body. Can be maintained in a state larger than the valve closing moment Mc.
次に、３種類の弁体Ａ〜Ｃを用いた検証実験により実証されたスイング式逆止弁１の効果について説明する。この検証実験では、図４に示す従来の弁体Ａと、弁体７から拡張部１３を省略した弁体Ｂと、弁体７と同じ構造の弁体Ｃとを準備した上で、上流側からコンプレッサにより加圧された流体を流し、チャタリング発生が停止したときのコンプレッサ出力を夫々計測した。尚、弁体Ａの半径と弁体Ｂの半径と弁体Ｃの弁座半径は同一とされ、その他、弁ケース、アーム等の構成は何れも同じ仕様に設定されている。 Next, the effect of the swing type check valve 1 demonstrated by a verification experiment using three types of valve bodies A to C will be described. In this verification experiment, after preparing the conventional valve body A shown in FIG. 4, the valve body B in which the expansion portion 13 is omitted from the valve body 7, and the valve body C having the same structure as the valve body 7, the upstream side Then, the fluid pressurized by the compressor was flowed, and the compressor output when chattering stopped was measured. The radius of the valve body A, the radius of the valve body B, and the valve seat radius of the valve body C are the same, and the configuration of the valve case, the arm, etc. are all set to the same specification.
検証実験の結果を下記対比表に示す。
以上のように、弁体Ｂ，Ｃは、弁体Ａに比べて軽量化されているため、チャタリング発生域を低流量（低圧）側に移動でき、チャタリングが早期に抑制されている。
弁体Ｃは、弁体Ｂに比べて弁体重量は増加しているものの、拡張部１３による受圧面積の拡大により、開弁状態における揚弁力を増加でき、弁体Ｂよりもチャタリングの抑制効果が格段に高いことが分かる。
The results of the verification experiment are shown in the following comparison table.
As described above, since the valve bodies B and C are lighter than the valve body A, the chattering generation region can be moved to the low flow rate (low pressure) side, and chattering is suppressed early.
Although the valve body weight is increased compared with the valve body B, the valve body C can increase the valve lift force in the valve-open state due to the expansion of the pressure receiving area by the expansion portion 13, and can suppress chattering more than the valve body B. It turns out that the effect is remarkably high.
スイング式逆止弁１によれば、弁部７ａの少なくとも一部から弁体７の径方向外側へ張り出した拡張部１３を設けたことにより、開弁状態における流体を受ける弁体７の受圧面積を従来型の弁体Ａの受圧面積よりも増加することができるため、開弁により弁体７上流側の流体圧が減少しても、弁体７に作用する揚弁力の低下を抑制でき、弁体７と弁座４との当接頻度を抑制してチャタリングの発生を回避することができる。 According to the swing type check valve 1, the pressure receiving area of the valve body 7 that receives the fluid in the valve-opened state is provided by providing the expansion portion 13 that protrudes from at least a part of the valve portion 7a to the radially outer side of the valve body 7. Therefore, even if the fluid pressure on the upstream side of the valve body 7 is reduced by opening the valve, it is possible to suppress a decrease in the lift force acting on the valve body 7. The occurrence of chattering can be avoided by suppressing the contact frequency between the valve element 7 and the valve seat 4.
拡張部１３の軸心方向の厚さが弁部７ａの軸心方向の厚さよりも小さく形成され、拡張部１３は、弁体７が閉弁状態のとき弁座４の外周側の壁部２ｄから流路３を流れる流体の流れ方向の下流側へ離隔するように形成されたため、閉弁状態のとき、拡張部１３が弁座４の外周側の壁部２ｄと当接しないため、拡張部１３の軸心方向の厚さを小さくすることができ、弁体７の軽量化によりチャタリングの発生を一層防止することができる。 The thickness of the expansion portion 13 in the axial direction is smaller than the thickness of the valve portion 7a in the axial direction, and the expansion portion 13 has a wall portion 2d on the outer peripheral side of the valve seat 4 when the valve body 7 is closed. Since the expansion portion 13 does not contact the wall portion 2d on the outer peripheral side of the valve seat 4 when the valve is closed, the expansion portion is separated from the downstream portion in the flow direction of the fluid flowing through the flow path 3 from the The thickness in the axial direction of 13 can be reduced, and chattering can be further prevented by reducing the weight of the valve body 7.
次に、前記実施例を部分的に変更した変形例について説明する。
１〕前記実施例においては、拡張部を弁部の下流端全周から径方向外側へ張り出した例を説明したが、少なくとも開弁状態における流体の受圧面積を閉弁状態における流体の受圧面積よりも増加出来ればよく、全周のうちの一部から部分的に径方向外側へ張り出した拡張部であっても良い。また、他のチャタリング防止技術と併用することも可能である。
Next, a modification in which the above embodiment is partially changed will be described.
1) In the above-described embodiment, the example in which the extended portion extends radially outward from the entire circumference of the downstream end of the valve portion has been described. Can be increased, and may be an extended portion that partially protrudes radially outward from a part of the entire circumference. It can also be used in combination with other chattering prevention techniques.
２〕前記実施例においては、流体として気体用のスイング式逆止弁の例を説明したが、液体用のスイング式逆止弁に適用することも可能である。
３〕その他、当業者であれば、本発明の趣旨を逸脱することなく、前記実施例に種々の変更を付加した形態で実施可能であり、本発明はそのような変更形態も包含するものである。
2] In the above embodiment, the example of the swing type check valve for gas as the fluid has been described. However, the present invention can be applied to a swing type check valve for liquid.
3) In addition, those skilled in the art can implement the present invention by adding various modifications to the embodiments without departing from the spirit of the present invention, and the present invention includes such modifications. is there.
本発明は、流路を流れる流体の逆流を防止し、流体を一方向のみに流すスイング式逆止弁において、開弁状態における流体を受ける弁体の受圧面積を閉弁状態における流体を受ける弁体の受圧面積よりも増加したため、逆止弁機能の向上とチャタリング防止とを両立できる。 The present invention relates to a swing type check valve that prevents a back flow of a fluid flowing in a flow path and flows a fluid in only one direction, and a pressure receiving area of a valve body that receives the fluid in the opened state is a valve that receives the fluid in the closed state Since the pressure receiving area of the body has increased, it is possible to improve both the check valve function and prevent chattering.
１ スイング式逆止弁
２ 弁ケース
２ｄ 壁部
３ 流路
３ａ 入口部
３ｂ 出口部
４ 弁座
５ アーム
６ 回動軸
７ 弁体
７ａ 弁部
１３ 拡張部
DESCRIPTION OF SYMBOLS 1 Swing type check valve 2 Valve case 2d Wall part 3 Flow path 3a Inlet part 3b Outlet part 4 Valve seat 5 Arm 6 Rotating shaft 7 Valve body 7a Valve part 13 Expansion part
Claims (1)
前記弁体の外周部分に前記弁座に当接する弁部を形成すると共に、前記弁体に前記弁部の少なくとも一部から弁体の径方向外側へ張り出した拡張部を設け、
前記拡張部の軸心方向の厚さが弁部の軸心方向の厚さよりも小さく形成され、
前記拡張部は、前記弁体が閉弁状態のとき前記弁座の外周側の壁部から前記流路を流れる流体の流れ方向の下流側へ離隔するように形成されたことを特徴とするスイング式逆止弁。 A valve case in which a flow path extending from the inlet portion to the outlet portion is formed, a valve seat provided in the middle of the flow passage, and an arm capable of swinging around a rotation shaft provided above the valve seat And a swing type check valve in which the valve body is closed by its own weight.
Forming a valve portion that contacts the valve seat on an outer peripheral portion of the valve body, and providing the valve body with an extended portion that protrudes radially outward of the valve body from at least a portion of the valve portion ;
A thickness in the axial direction of the extension portion is formed smaller than a thickness in the axial direction of the valve portion,
The extension portion is formed so as to be separated from the wall portion on the outer peripheral side of the valve seat to the downstream side in the flow direction of the fluid flowing through the flow path when the valve body is in a closed state. Type check valve.
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| CN105179755A (en) * | 2014-06-03 | 2015-12-23 | 中核苏阀科技实业股份有限公司 | Swing axial-flow check valve |
| CN104847930B (en) * | 2015-04-18 | 2017-06-30 | 张新丰 | Water hammer-resistant slow closing swing check valve |
| KR102582102B1 (en) * | 2016-05-11 | 2023-09-22 | 에스케이매직 주식회사 | Water leak prevented humidifier |
| ES2677256B1 (en) * | 2017-01-31 | 2019-05-27 | Sener Ing & Sist | Unidirectional valve for a device for capturing wave energy |
| CN107061804B (en) * | 2017-04-11 | 2018-11-02 | 张新丰 | Protecting against shock swing check valve |
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| US4249568A (en) * | 1978-10-02 | 1981-02-10 | Duggan Daniel C | Backflow preventer valve |
| JPS58153766U (en) * | 1982-04-08 | 1983-10-14 | 出光石油化学株式会社 | non-return valve |
| JPH0335378U (en) * | 1989-08-17 | 1991-04-05 | ||
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