JP4137614B2

JP4137614B2 - Self-priming pump

Info

Publication number: JP4137614B2
Application number: JP2002351558A
Authority: JP
Inventors: 眞吉野; 洋司佐藤
Original assignee: 株式会社電業社機械製作所
Priority date: 2002-12-03
Filing date: 2002-12-03
Publication date: 2008-08-20
Anticipated expiration: 2022-12-03
Also published as: JP2004183561A

Description

【０００１】
【発明の属する技術分野】
本発明は、自吸運転の際には、気液交換が効率良くできて速やかに揚水運転に移行できるとともに、揚水運転の際には、ポンプ効率が良くなるようにした自吸式ポンプに関するものである。
【０００２】
【従来の技術】
自吸式ポンプは、通常運転となる揚水運転機能と、揚水運転に移行するための起動運転となる自吸運転機能とを、併せ持つ必要がある。揚水運転に速やかに移行するためには、自吸運転を短時間で完了しなければならず、そのためには揚水管や吸込曲管や吸込室や羽根車および羽根車室に溜まっている空気を速やかに排出しなければならない。そこで、羽根車の回転により、羽根車室から吐出室に吐き出させる気液混合水から空気を効率的に分離し、空気が分離された水のみを吸込室に戻して、揚水管や吸込曲管や吸込室や羽根車および羽根車室を水で速やかに充満する技術の一例が、特公昭３８−１５５２９号公報や特公昭５０−２１６８２号公報に示されている。
【０００３】
上記特公昭３８−１５５２９号公報や特公昭５０−２１６８２号公報に示される技術は、以下のごときものである。ポンプケーシングの羽根車室から吐出室に吐き出される水の一部を、流れ方向と直交する断面で内形が略円形な吐出室に、その壁に沿って略接線方向で流入させることで、吐出室内を流れる水流を旋回させ、この旋回による遠心分離作用によって、吐出室の内壁側近くに水を集めるとともに中心側に気体を集め、吐出室の内壁側近くの水のみを吸込室に戻すようにしたものである。
【０００４】
また、揚水運転において、ポンプ効率を良くするためには、吐出室から吸込室への戻り水の流量が極力少ないことが望ましい。なぜならば、戻り水の流量が多いということは、その分実質的な揚水量が減少してポンプ効率の低下となる。そして、吐出室の吐出圧力と吸込室の吸込圧力の差が大きくなればなるほど、戻り水の流量が多くなり、よりポンプ効率の低下を生ずる。
【０００５】
【発明が解決しようとする課題】
上記特公昭３８−１５５２９号公報や特公昭５０−２１６８２号公報に示される技術にあっては、効率良く空気が分離排除されて、速やかに揚水運転に移行することができる。しかるに、揚水運転において戻り水の流量が比較的に多く、充分なポンプ効率が得られ難いという問題点があった。
【０００６】
そこで、戻り水の流量を零とする目的で、戻り水の水路に開閉弁を設け、自吸運転の際には、この開閉弁を開成して空気の分離排除を迅速になし、揚水運転に移行した後は、この開閉弁を閉成することで、戻り水の流量を零とし、もってポンプ効率を向上させる技術も考えられる。しかし、開閉弁を設けることは、その制御機構が複雑になるとともに、異物を多く含む水を扱う場合には、異物が開閉弁に噛み込まれるなどにより、開閉操作不可能となってポンプの運転に支障を生ずる虞がある。
【０００７】
本発明は、上述のごとき従来技術の事情に鑑みてなされたもので、開閉弁を用いることなし、自吸運転において、迅速に気体を分離排除できて速やかに揚水運転に移行でき、しかも揚水運転において、戻り流量が少ない自吸式ポンプを提供することを目的とする。
【０００８】
【課題を解決するための手段】
かかる目的を達成するために本発明の自吸式ポンプは、ポンプケーシングの吐出管の流体を旋回させて気液分離作用を行う自吸式ポンプにおいて、前記吐出管の壁に、前記流体の旋回方向で略接線方向の流出口を開口し、前記ポンプケーシングの外に略垂直方向を軸方向とする円筒状の戻り流量規制部を設け、この戻り流量規制部の側壁に略接線方向の流入口を開口し、前記流出口と前記流入口を流入連通管で連通し、前記戻り流量規制部の円筒状の略軸心位置に戻り連通管の一端を開口し、前記戻り連通管の他端を前記ポンプケーシングの吸込室に開口して構成されている。
【０００９】
また、ポンプケーシングの羽根車室から吐出室に吐出される流体の一部を、流れ方向と直交する断面で内形が略円形な前記吐出室内に略接線方向で流入させて前記吐出室内の流体を旋回させ、前記流体が略接線方向に流入される位置より下流側の前記吐出室の壁に、前記流体の旋回方向で略接線方向の流出口を開口し、前記ポンプケーシングの外に略垂直方向を軸方向とする円筒状の戻り流量規制部を設け、この戻り流量規制部の側壁に略接線方向の流入口を開口し、前記流出口と前記流入口を流入連通管で連通し、前記戻り流量規制部の円筒状の略軸心位置に戻り連通管の一端を開口し、前記戻り連通管の他端を前記ポンプケーシングの吸込室に開口して構成しても良い。
【００１０】
そして、羽根車の回転軸心と直交方向の前記吐出室または前記羽根車室の壁に略接線方向に導出口を開口し、前記導出口より下流側の前記吐出室の壁に流れ方向に対して直交する断面で略接線方向に導入口を開口し、前記導出口と前記導入口を連通管で連通して構成することもできる。
【００１１】
さらに、前記羽根車室または前記吐出室に、流路を分割するように流路方向に沿って仕切壁を設けて流体の一部が流入する流入室を形成し、しかも前記流入室が前記仕切壁により前記吐出室に隣接するようになし、前記吐出室の壁に流れ方向に対して直交する断面で略接線方向に開口する連通孔を前記仕切壁に穿設して構成することも可能である。
【００１２】
【発明の実施の形態】
以下、本発明の第１実施例を図１ないし図８を参照して説明する。図１は、本発明の自吸式ポンプを両吸込渦巻ポンプに適用した第１実施例の全体配管図である。図２は、図１の自吸式ポンプのポンプ軸に直交する面で切断した一部切り欠き縦断面図である。図３は、図１の自吸式ポンプのポンプ軸を含む面で切断した縦断面図である。図４は、図２のＡ−Ａ矢視端面図である。図５は、図２の吐出室付近のＢ−Ｂ矢視断面図である。図６は、図２のＣ矢視部分図である。図７は、戻り流量規制部の作用を説明する縦断面図である。図８は、本発明の自吸式ポンプと従来例との流入圧力に対する戻り流量の傾向を示す図である。
【００１３】
まず、第１実施例は、本発明の自吸式ポンプを両吸込渦巻ポンプに適用したものであり、図１に示すごとく、ポンプケーシング１０の吸込側に、吸込曲管１４および揚水管１６が順次に連通接続され、この揚水管１６の下端開口部が吸込水槽１８の水面下に没入される。なお、ポンプケーシング１０の吸込側は、ポンプケーシング１０内で流路が２つに分岐され、これらの分岐された２つの流路がそれぞれ両側の吸込室５２，５２に連通されている。また、ポンプケーシング１０の吐出側に、逆止弁２０と主開閉弁２２および吐出管２４が順次に連通接続される。さらに、ポンプケーシング１０の外に、戻り流量規制部２６が適宜に配設され、ポンプケーシング１０に後述するごとく配管連通されている。
【００１４】
そして、ポンプケーシング１０内の構造は、図２に示すごとく、渦巻状の略中心に駆動機（図示せず）に駆動連結されて回転されるポンプ軸２８が回転自在に配設され、このポンプ軸２８に羽根車３０が固定され、矢印Ｅの方向に駆動回転される。
【００１５】
さらに、羽根車室３２または吐出室３４の壁で、ポンプ軸２８に直交する面と交叉する位置で渦巻状に対する略接線方向に導出口３６が開口される。また、この導出口３６より下流側の吐出室３４で、吐出室３４の流れ方向に対して直交する断面で内形が略円形の壁に、図５に示すごとく、略接線方向に導入口３８が開口される。そして、導出口３６と導入口３８が、図６にその外観を示すごとく、連通管４０で連通される。
【００１６】
そして、吐出室３４の導入口３８が開口された位置よりもさらに下流側で、流れ方向と直交する断面の内形が略円形の壁に、図４に示すごとく、略接線方向に流出口４２が開口される。この流出口４２に一端が連通される流入連通管４４の他端は、戻り流量規制部２６に開口した流入口４６に連通される。なお、吐出室３４の水流は、後述するごとく、流れ方向の中心を軸心とする軸回りの旋回流を生じ、流出口４２はその旋回方向に沿うように開口されている。
【００１７】
戻り流量規制部２６の構造は、垂直方向を軸方向とする円筒状でその上下が閉塞され、この円筒状の側壁の上部分に、略接線方向に流入口４６が開口される。そして、底面の中心の略軸心位置に孔４８が穿設され、この孔４８に戻り連通管５０の一端開口が連通される。この戻り連通管５０は、戻り流量規制部２６の外側に設けられている。しかも、図３に示すごとく、途中で２つに分岐され、分岐された２つの他端開口が、ポンプケーシング１０の２つの吸込室５２，５２にそれぞれ連通される。
【００１８】
かかる構成の第１実施例において、運転開始前に主開閉弁２２を開成した状態でポンプケーシング１０内に水を充満させ、駆動機（図示せず）を起動して羽根車３０を駆動回転させ、その後に主開閉弁２２を開成する。すると、羽根車３０の回転に伴い、吸込室５２，５２の水が羽根車３０を介して羽根車室３２に移動される。そこで、吸込室５２，５２内が負圧となり、吸込曲管１４および揚水管１６内が負圧となり、揚水管１６内の水位が上昇する。また、吸込曲管１４および揚水管１６内の空気が吸込室５２，５２に吸い込まれ、羽根車３０により水と空気が撹拌され、気液混合水となって羽根車室３２に吐き出される。さらに、羽根車室３２に吐き出された気液混合水は、渦巻状のポンプケーシング１０の内壁に沿って、吐出室３４へ移行される。吐出室３４へ移行された気液混合水の大部分は、吐出室３４を軸方向に流れるが、その一部が導出口３６から連通管４０を経て導入口３８から再び吐出室３４に流入される。この導入口３８からの気液混合水の流入により、吐出室３４を軸方向に流れる気液混合水に、軸心回りの旋回流が生ずる。この旋回流による遠心分離作用で、水は吐出室３４の内壁近くに集まり、空気は中心側の軸心近くに集まる。そこで、軸心近くに集まって、水と分離された空気は、主開閉弁２２を介して吐出管２４へと移行される。また、吐出室３４の内壁近くに集まった水は、吐出室３４の壁に略接線方向に開口された流出口４２に流入し、流入連通管４４を介して、流入口４６から戻り流量規制部２６の内壁に対して略接線方向に流入する。戻り流量規制部２６に流入した水は、底面の孔４８から戻り連通管５０を経て、ポンプケーシング１０の吸込室５２，５２に流入する。もって、空気が分離排除された水のみが吸込室５２，５２に再び戻ることで、空気が排除された分だけ、吸込室５２，５２の負圧が増大し揚水管１６内の水位がさらに上昇する。最終的には、ポンプケーシング１０と吸込曲管１４および揚水管１６などの全てが水で充満されて自吸運転が完了し、速やかに揚水運転へと移行される。
【００１９】
そして、揚水運転が開始されると、羽根車室３２の圧力が上昇して吐出室３４の圧力も上昇し、水の一部が流出口４２から流入連通管４４を経て戻り流量規制部２６へ流入口４６から流入する。ここで、圧力Ｐ１で流入口４６から戻り流量規制部２６に流入した水は、戻り流量規制部２６内で内壁に沿った渦流となり、底面近くで渦流の旋回径が小さくなって最終的に底面の中心にある孔４８からその流れ方向を略９０度ほど折り曲げるようにして戻り連通管５０に圧力Ｐ２で流入し、吸込室５２，５２へと戻される。これらの戻り流量規制部２６内での水の流れは、損失抵抗が大きく、流入口４６に流入する水の圧力Ｐ１に比べて、孔４８から流出する水の圧力Ｐ２は、大幅に小さなものとなる。そこで、図８に実線で示す特性のごとく、本発明では、流入口４６の流入圧力Ｐ１の増大に対して、戻り連通管５０へ流入する戻り流量の増大は比較的に緩やかである。
【００２０】
なお、図８に点線で示す特性は、本発明の戻り流量規制部２６を設けずに、吐出室３４に開口した流出口４２を、直接的に吸込室５２，５２に連通した場合の従来例であり、流入圧力Ｐ１の増大に伴い、約比例して戻り流量も増大している。
【００２１】
したがって、本発明の自吸式ポンプの第１実施例にあっては、戻り流量規制部２６を設けることで、吐出室３４の圧力が増大しても、吸込室５２，５２へ流入する戻り流量が比較的に少量に抑制することができる。このことから、揚水運転において、吐出室３４の圧力が増大しても、吸込室５２，５２への戻り流量は少なく、それだけポンプ効率が良いものとなる。
【００２２】
次に、本発明の第２実施例を図９ないし図１１を参照して説明する。図９は、本発明の自吸式ポンプの第２実施例のポンプ軸に直交する面で切断した一部切り欠き縦断面図である。図１０は、図９の自吸式ポンプのポンプ軸を含む面で切断した縦断面図である。図１１は、図９の吐出室付近のＤ−Ｄ矢視端面図である。図９ないし図１１において、図１ないし図８と同じまたは均等な部材には、同じ符号を付けて重複する説明を省略する。
【００２３】
第２実施例において、第１実施例と相違するところは、以下の構造にある。まず、図９に示すごとく、羽根車室３４に流路を分割するように流路方向に沿って仕切壁６０が設けられ、羽根車３０から吐き出された水の一部が流入する流入室６２が形成される。なお、この流入室６２は、仕切壁６０により吐出室３４に隣接している。そして、この仕切壁６０に連通孔６４が穿設され、流入室６２と吐出室３４が連通される。しかも、連通孔６４は、吐出室３４の壁に流れ方向に対して直交する断面で略接線方向に開口される。ここで、流入室６２を形成する仕切壁６０は、吐出室３４に流路方向に沿うように設けられても良く、羽根車３０から吐出する流水の一部が流入し、仕切壁６０に穿設した連通孔６４により、水が吐出室３４に内壁に沿って略接線方向に流入できれば、いかなる構造であっても良い。なお、第２実施例において、第１実施例における導出口３６と連通管４０および導入口３８は設けられていない。
【００２４】
また、戻り流量規制部２６に、吐出室３４に開口した流出口４２より流入連結管４４を介して、戻り流量規制部２６の内部に流入口４６から旋回流となるように水が流入されることは第１実施例と同様である。しかし、戻り流量規制部２６の底面には孔４８が穿設されず、円筒状の上面を貫通して戻り連通管６６の一端が略軸心位置の底面近くで開口するように配設され、この戻り連通管６６が途中で２つに分岐されて２つの他端が吸込室５２，５２にそれぞれ開口される。
【００２５】
かかる構成の第２実施例では、流入室６２に流入した水が、連通孔６４を介して、図１１に示すごとく、吐出室３４の内壁に沿って略接線方向に流出され、吐出室３４の流れに旋回流を生じさせる。もって、第１実施例と同様に、この旋回流によって気液分離作用がなされる。そして、吐出室３４の内壁近くに集まった、気体が分離排除された水が、戻り流量規制部２６内に旋回流となって流入され、さらに圧力の低下する旋回流の中心の略軸心位置で底面近くに開口された戻り連通管６６を介して、大きな損失抵抗をもって吸込室５２，５２に戻される。
【００２６】
したがって、第２実施例も、第１実施例と同様に自吸運転から速やかに揚水運転に移行され、揚水運転において吸込室５２，５２への戻り流量は少なく、優れたポンプ効率が得られる。
【００２７】
さらに、本発明の第３実施例を図１２を参照して説明する。図１２は、本発明の自吸式ポンプを片吸込渦巻ポンプに適用した第３実施例の外観図である。図１２において、図１ないし図８に示す部材と同じまたは均等な部材には、同じ符号を付けて重複する説明は省略する。図１２に示す第３実施例では、片吸込のため、戻り流量規制部２６からの戻り連通管５０が２つに分岐されることなしに吸込室５２に連通されている。図１２では、吐出室３４に設けた連通管４４により、吐出室３４の流水に旋回流を生じさせているが、第２実施例のごとき構造によって吐出室３４の流水に旋回流を生じさせても良いことは勿論である。
【００２８】
なお、上記実施例において、流体としての対象を水として説明したが、水以外の流体を対象とすることも可能である。また、気液分離作用を奏するために、吐出室３４の流水に流れ方向を軸心方向として軸回りの旋回流を生じさせる手段は、上記第１または第２実施例に限られるものでなく、旋回流を生じさせ得るならば、いかなる手段であっても良い。例えば、外部に設けたポンプで、流体を吐出室３４の内壁に略接線方向に噴出させても良い。
【００２９】
【発明の効果】
以上説明したように本発明の自吸式ポンプは構成されているので、以下のごとき格別な作用効果を奏する。
【００３０】
請求項１記載の自吸式ポンプにあっては、戻り流量規制部により大きな損失抵抗を生じさせることで、吐出室から吸込室へ戻る流量を少量とすることができ、戻り流量が少ない分だけポンプ効率を良くすることができる。
【００３１】
請求項２ないし４記載のいずれの自吸式ポンプにあっても、羽根車から吐き出されて羽根車室または吐出室を流れる流体の一部によって、吐出室の流体に旋回流を生じさせて気液分離作用をさせ、もって迅速に自吸運転から揚水運転に移行できる。しかも、揚水運転では、請求項１と同様に、優れたポンプ効率が得られる。
【００３２】
請求項５または６記載の自吸式ポンプは、円筒状の戻り流量規制部の略軸心位置で底面または底面近くに戻り連通管の一端を開口したので、戻り連通管に流入する流路の損失抵抗が大きく、戻り連通管に流入する流体の圧力が低くなる。そこで、吸込室への戻り流量が少量となり、もってポンプ効率を向上させ得る。
【図面の簡単な説明】
【図１】本発明の自吸式ポンプを両吸込渦巻ポンプに適用した第１実施例の全体配管図である。
【図２】図１の自吸式ポンプのポンプ軸に直交する面で切断した一部切り欠き縦断面図である。
【図３】図１の自吸式ポンプのポンプ軸を含む面で切断した縦断面図である。
【図４】図２のＡ−Ａ矢視端面図である。
【図５】図２の吐出室付近のＢ−Ｂ矢視断面図である。
【図６】図２のＣ矢視部分図である。
【図７】戻り流量規制部の作用を説明する縦断面図である。
【図８】本発明の自吸式ポンプと従来例との流入圧力に対する戻り流量の傾向を示す図である。
【図９】本発明の自吸式ポンプの第２実施例のポンプ軸に直交する面で切断した一部切り欠き縦断面図である。
【図１０】図９の自吸式ポンプのポンプ軸を含む面で切断した縦断面図である。
【図１１】図９の吐出室付近のＤ−Ｄ矢視端面図である。
【図１２】本発明の自吸式ポンプを片吸込渦巻ポンプに適用した第３実施例の外観図である。
【符号の説明】
１０ポンプケーシング
１４吸込曲管
１６揚水管
１８吸込水槽
２０逆止弁
２２主開閉弁
２４吐出管
２６戻り流量規制部
２８ポンプ軸
３０羽根車
３２羽根車室
３４吐出室
３６導出口
３８導入口
４０連通管
４２流出口
４４流入連通管
４６流入口
４８孔
５０，６６戻り連通管
５２吸込室
６０仕切壁
６２流入室
６４連通孔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-priming pump that can efficiently perform gas-liquid exchange during self-priming operation and can quickly shift to pumping operation, and has improved pump efficiency during pumping operation. It is.
[0002]
[Prior art]
The self-priming pump needs to have both a pumping operation function that is a normal operation and a self-priming operation function that is a start-up operation for shifting to a pumping operation. In order to make a quick transition to the pumping operation, the self-priming operation must be completed in a short period of time. To that end, the air accumulated in the pumping pipe, suction bent pipe, suction chamber, impeller, and impeller chamber must be removed. It must be discharged immediately. Therefore, by rotating the impeller, the air is efficiently separated from the gas-liquid mixed water discharged from the impeller chamber to the discharge chamber, and only the water from which the air has been separated is returned to the suction chamber, and the pumping pipe and the suction bent pipe An example of a technique for quickly filling a suction chamber, an impeller, and an impeller chamber with water is disclosed in Japanese Patent Publication Nos. 38-15529 and 50-21682.
[0003]
The techniques disclosed in Japanese Patent Publication No. 38-15529 and Japanese Patent Publication No. 50-21682 are as follows. A part of the water discharged from the impeller chamber of the pump casing into the discharge chamber is allowed to flow in a substantially tangential direction along the wall of the discharge chamber having a cross section orthogonal to the flow direction and having a substantially circular inner shape. The water flow in the room is swirled, and the centrifugal action resulting from this swirling collects water near the inner wall of the discharge chamber, collects gas at the center, and returns only water near the inner wall of the discharge chamber to the suction chamber. It is a thing.
[0004]
Further, in the pumping operation, in order to improve the pump efficiency, it is desirable that the flow rate of the return water from the discharge chamber to the suction chamber is as small as possible. This is because the fact that the flow rate of return water is large means that the amount of pumped water is reduced correspondingly and the pump efficiency is lowered. As the difference between the discharge pressure in the discharge chamber and the suction pressure in the suction chamber increases, the flow rate of the return water increases and the pump efficiency is further reduced.
[0005]
[Problems to be solved by the invention]
In the technique disclosed in the above Japanese Patent Publication No. 38-15529 and Japanese Patent Publication No. 50-21682, air is efficiently separated and removed, and the pumping operation can be quickly performed. However, in the pumping operation, there is a problem that the flow rate of the return water is relatively large and it is difficult to obtain sufficient pump efficiency.
[0006]
Therefore, for the purpose of reducing the flow rate of the return water, an open / close valve is provided in the return water channel, and during the self-priming operation, this open / close valve is opened to quickly separate and eliminate the air for the pumping operation. After the transition, a technique for improving the pump efficiency by closing the on-off valve so that the flow rate of the return water is zero can be considered. However, providing an on-off valve complicates the control mechanism, and when handling water containing a large amount of foreign matter, the opening and closing operation becomes impossible due to foreign matter being caught in the on-off valve. May cause trouble.
[0007]
The present invention has been made in view of the circumstances of the prior art as described above, and without using an on-off valve, in self-priming operation, gas can be quickly separated and removed, and can be quickly transferred to a pumping operation. An object of the present invention is to provide a self-priming pump with a low return flow rate.
[0008]
[Means for Solving the Problems]
In order to achieve this object, the self-priming pump of the present invention is a self-priming pump that performs gas-liquid separation by swirling the fluid in the discharge pipe of the pump casing. A substantially tangential outflow opening is provided, a cylindrical return flow restricting portion having an axial direction in the substantially vertical direction is provided outside the pump casing, and a substantially tangential inflow opening is provided on a side wall of the return flow restricting portion. The outlet and the inlet are connected by an inflow communication pipe, one end of the return communication pipe is opened at the substantially cylindrical center position of the return flow restricting portion, and the other end of the return communication pipe is connected. An opening is formed in the suction chamber of the pump casing.
[0009]
Further, a part of the fluid discharged from the impeller chamber of the pump casing into the discharge chamber is caused to flow in a substantially tangential direction into the discharge chamber having a substantially circular inner shape in a cross section perpendicular to the flow direction. And a substantially tangential outlet in the swirl direction of the fluid is opened in the wall of the discharge chamber downstream from the position where the fluid flows in a substantially tangential direction, and is substantially perpendicular to the outside of the pump casing. A cylindrical return flow rate restricting portion having an axial direction as a direction, an approximately tangential inflow opening is opened in a side wall of the return flow restricting portion, and the outflow port and the inflow port are communicated with an inflow communication pipe; One end of the return communication pipe may be opened at the cylindrical substantially axial center position of the return flow restricting portion, and the other end of the return communication pipe may be opened in the suction chamber of the pump casing.
[0010]
A discharge port is opened in a direction substantially tangential to the discharge chamber or the impeller chamber wall perpendicular to the rotation axis of the impeller, and the discharge chamber wall downstream of the discharge port is directed to the flow direction. The introduction port may be opened in a substantially tangential direction in a cross section orthogonal to each other, and the lead-out port and the introduction port may be communicated with each other through a communication pipe.
[0011]
Further, the impeller chamber or the discharge chamber is provided with a partition wall along the flow path direction so as to divide the flow path to form an inflow chamber into which a part of the fluid flows, and the inflow chamber is the partition wall. The wall may be adjacent to the discharge chamber, and a communication hole that opens in a substantially tangential direction in a cross section orthogonal to the flow direction may be formed in the partition wall. is there.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall piping diagram of a first embodiment in which the self-priming pump of the present invention is applied to both suction centrifugal pumps. 2 is a partially cutaway longitudinal sectional view taken along a plane orthogonal to the pump axis of the self-priming pump of FIG. 3 is a longitudinal sectional view taken along a plane including the pump shaft of the self-priming pump of FIG. 4 is an end view taken along arrow AA in FIG. 5 is a cross-sectional view of the vicinity of the discharge chamber in FIG. FIG. 6 is a partial view of FIG. FIG. 7 is a longitudinal sectional view for explaining the operation of the return flow rate restricting portion. FIG. 8 is a diagram showing the tendency of the return flow rate with respect to the inflow pressure between the self-priming pump of the present invention and the conventional example.
[0013]
First, in the first embodiment, the self-priming pump of the present invention is applied to both suction centrifugal pumps. As shown in FIG. 1, the suction bent pipe 14 and the pumping pipe 16 are provided on the suction side of the pump casing 10. The lower end opening of the pumping pipe 16 is immersed under the water surface of the suction water tank 18. The suction side of the pump casing 10 is divided into two flow paths in the pump casing 10, and these two branched flow paths are connected to suction chambers 52, 52 on both sides, respectively. A check valve 20, a main on-off valve 22, and a discharge pipe 24 are sequentially connected to the discharge side of the pump casing 10. Further, a return flow rate restricting portion 26 is appropriately disposed outside the pump casing 10 and is connected to the pump casing 10 by piping as will be described later.
[0014]
As shown in FIG. 2, the pump casing 10 has a structure in which a pump shaft 28 that is driven and connected to a drive unit (not shown) is rotatably disposed at a substantially spiral center. An impeller 30 is fixed to the shaft 28 and is driven to rotate in the direction of arrow E.
[0015]
Further, the outlet port 36 is opened in a direction substantially tangential to the spiral at a position intersecting with a surface orthogonal to the pump shaft 28 on the wall of the impeller chamber 32 or the discharge chamber 34. Further, in the discharge chamber 34 on the downstream side of the outlet port 36, the inner shape is a substantially circular wall in a cross section orthogonal to the flow direction of the discharge chamber 34, and as shown in FIG. Is opened. The outlet 36 and the inlet 38 are communicated with each other through a communication pipe 40 as shown in FIG.
[0016]
Further, on the further downstream side of the position where the introduction port 38 of the discharge chamber 34 is opened, the inner shape of the cross section perpendicular to the flow direction is a substantially circular wall, as shown in FIG. Is opened. The other end of the inflow communication pipe 44 whose one end communicates with the outflow port 42 is communicated with an inflow port 46 that opens to the return flow rate restricting portion 26. As will be described later, the water flow in the discharge chamber 34 generates a swirling flow around an axis centered in the flow direction, and the outlet 42 is opened along the swirling direction.
[0017]
The structure of the return flow restricting portion 26 is a cylindrical shape whose axial direction is the vertical direction, and its upper and lower portions are closed, and an inlet 46 is opened in a substantially tangential direction on the upper portion of the cylindrical side wall. A hole 48 is formed at a substantially axial center position at the center of the bottom surface, and the one end opening of the communication pipe 50 is communicated with the hole 48. The return communication pipe 50 is provided outside the return flow rate restricting unit 26. Moreover, as shown in FIG. 3, the two branches at the other end are communicated with the two suction chambers 52, 52 of the pump casing 10.
[0018]
In the first embodiment having such a configuration, the pump casing 10 is filled with water with the main on-off valve 22 opened before the operation is started, and a driving machine (not shown) is activated to drive and rotate the impeller 30. Then, the main on-off valve 22 is opened. Then, as the impeller 30 rotates, the water in the suction chambers 52 and 52 is moved to the impeller chamber 32 via the impeller 30. Therefore, the suction chambers 52 and 52 have negative pressure, the suction bent pipe 14 and the pumping pipe 16 have negative pressure, and the water level in the pumping pipe 16 rises. Further, the air in the suction bent pipe 14 and the pumping pipe 16 is sucked into the suction chambers 52 and 52, the water and air are stirred by the impeller 30, and discharged into the impeller chamber 32 as gas-liquid mixed water. Further, the gas-liquid mixed water discharged into the impeller chamber 32 is transferred to the discharge chamber 34 along the inner wall of the spiral pump casing 10. Most of the gas-liquid mixed water transferred to the discharge chamber 34 flows in the discharge chamber 34 in the axial direction, but a part of the mixed liquid flows into the discharge chamber 34 from the introduction port 38 through the communication pipe 40 again. The By the inflow of the gas-liquid mixed water from the introduction port 38, a swirling flow around the axis is generated in the gas-liquid mixed water flowing in the discharge chamber 34 in the axial direction. By this centrifugal separation action by the swirling flow, water gathers near the inner wall of the discharge chamber 34 and air gathers near the central axis. Therefore, the air collected near the axis and separated from the water is transferred to the discharge pipe 24 via the main on-off valve 22. Further, the water collected near the inner wall of the discharge chamber 34 flows into the outlet 42 opened substantially tangentially to the wall of the discharge chamber 34, and returns from the inlet 46 through the inlet communication pipe 44. It flows in a substantially tangential direction with respect to the inner wall of 26. The water that has flowed into the return flow regulating portion 26 flows into the suction chambers 52 and 52 of the pump casing 10 through the return communication pipe 50 from the hole 48 on the bottom surface. Therefore, only the water from which the air has been separated and removed returns to the suction chambers 52 and 52 again, so that the negative pressure in the suction chambers 52 and 52 increases and the water level in the pumping pipe 16 further increases by the amount of the air that has been removed. To do. Eventually, all of the pump casing 10, the suction bend pipe 14, the pumping pipe 16 and the like are filled with water, the self-priming operation is completed, and the pumping operation is promptly shifted.
[0019]
When the pumping operation is started, the pressure in the impeller chamber 32 is increased and the pressure in the discharge chamber 34 is also increased, and a part of the water is returned from the outlet 42 to the return flow regulating portion 26 through the inflow communication pipe 44. It flows in from the inlet 46. Here, the water flowing into the return flow restricting portion 26 from the inlet 46 at the pressure P1 becomes a vortex along the inner wall in the return flow restricting portion 26, and the swirl diameter of the vortex becomes small near the bottom surface and finally the bottom surface. From the hole 48 in the center of the gas, the flow direction is bent by about 90 degrees, and the return communication pipe 50 flows into the return communication pipe 50 with pressure P2 and is returned to the suction chambers 52 and 52. The flow of water in these return flow restricting portions 26 has a large loss resistance, and the pressure P2 of water flowing out from the hole 48 is much smaller than the pressure P1 of water flowing into the inlet 46. Become. Therefore, as indicated by the solid line in FIG. 8, in the present invention, the increase in the return flow rate flowing into the return communication pipe 50 is relatively gradual with respect to the increase in the inflow pressure P1 at the inlet 46.
[0020]
The characteristic indicated by the dotted line in FIG. 8 is a conventional example in the case where the outlet 42 opened to the discharge chamber 34 is directly communicated with the suction chambers 52 and 52 without providing the return flow restricting portion 26 of the present invention. As the inflow pressure P1 increases, the return flow rate also increases approximately proportionally.
[0021]
Therefore, in the first embodiment of the self-priming pump of the present invention, the return flow rate restricting portion 26 is provided so that the return flow rate that flows into the suction chambers 52 and 52 even if the pressure in the discharge chamber 34 increases. Can be suppressed to a relatively small amount. For this reason, in the pumping operation, even if the pressure in the discharge chamber 34 increases, the return flow rate to the suction chambers 52 and 52 is small, and the pump efficiency is improved accordingly.
[0022]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a partially cutaway longitudinal sectional view taken along a plane orthogonal to the pump shaft of the second embodiment of the self-priming pump of the present invention. FIG. 10 is a longitudinal sectional view taken along a plane including the pump shaft of the self-priming pump of FIG. 11 is an end view of the vicinity of the discharge chamber in FIG. 9 to 11, the same or equivalent members as those in FIGS. 1 to 8 are denoted by the same reference numerals and redundant description is omitted.
[0023]
The second embodiment is different from the first embodiment in the following structure. First, as shown in FIG. 9, a partition wall 60 is provided along the flow path direction so as to divide the flow path in the impeller chamber 34, and an inflow chamber 62 into which a part of the water discharged from the impeller 30 flows. Is formed. The inflow chamber 62 is adjacent to the discharge chamber 34 by the partition wall 60. A communication hole 64 is formed in the partition wall 60 so that the inflow chamber 62 and the discharge chamber 34 are communicated with each other. In addition, the communication hole 64 is opened in a substantially tangential direction in a cross section orthogonal to the flow direction on the wall of the discharge chamber 34. Here, the partition wall 60 that forms the inflow chamber 62 may be provided along the flow path direction in the discharge chamber 34, and a part of the flowing water discharged from the impeller 30 flows into the partition wall 60. Any structure may be used as long as water can flow into the discharge chamber 34 in the substantially tangential direction along the inner wall by the communication hole 64 provided. In the second embodiment, the outlet 36, the communication pipe 40, and the inlet 38 in the first embodiment are not provided.
[0024]
Further, water flows into the return flow rate restricting portion 26 from the outlet port 42 opened in the discharge chamber 34 through the inflow connecting pipe 44 so as to form a swirl flow from the inlet 46 into the return flow rate restricting portion 26. This is the same as in the first embodiment. However, no hole 48 is formed in the bottom surface of the return flow restricting portion 26, and one end of the return communication pipe 66 is disposed so as to open near the bottom surface at a substantially axial position through the cylindrical upper surface. The return communication pipe 66 is branched into two in the middle, and the two other ends are opened to the suction chambers 52 and 52, respectively.
[0025]
In the second embodiment having such a configuration, the water flowing into the inflow chamber 62 flows out in a substantially tangential direction along the inner wall of the discharge chamber 34 through the communication hole 64 as shown in FIG. A swirling flow is generated in the flow. Thus, as in the first embodiment, the gas-liquid separation action is performed by this swirling flow. The water collected near the inner wall of the discharge chamber 34 and from which the gas has been separated and removed flows into the return flow restricting portion 26 as a swirling flow, and the approximate axial center position of the swirling flow at which the pressure further decreases. Then, the air is returned to the suction chambers 52 and 52 with a large loss resistance through the return communication pipe 66 opened near the bottom.
[0026]
Accordingly, in the second embodiment as well, the self-priming operation is promptly shifted to the pumping operation as in the first embodiment, the return flow rate to the suction chambers 52 and 52 is small in the pumping operation, and excellent pump efficiency is obtained.
[0027]
Furthermore, a third embodiment of the present invention will be described with reference to FIG. FIG. 12 is an external view of a third embodiment in which the self-priming pump of the present invention is applied to a single suction centrifugal pump. In FIG. 12, the same or equivalent members as those shown in FIG. 1 to FIG. In the third embodiment shown in FIG. 12, the return communication pipe 50 from the return flow restricting portion 26 is communicated with the suction chamber 52 without being branched into two for the single suction. In FIG. 12, the communication pipe 44 provided in the discharge chamber 34 generates a swirling flow in the flowing water in the discharge chamber 34. However, the swirling flow is generated in the flowing water in the discharging chamber 34 by the structure as in the second embodiment. Of course, it is also good.
[0028]
In addition, in the said Example, although the object as a fluid was demonstrated as water, it is also possible to target fluids other than water. Further, means for generating a swirling flow around the axis with the flow direction set as the axial direction in the flowing water of the discharge chamber 34 in order to exert a gas-liquid separation action is not limited to the first or second embodiment, Any means may be used as long as it can generate a swirling flow. For example, the fluid may be ejected to the inner wall of the discharge chamber 34 in a substantially tangential direction with a pump provided outside .
[0029]
【The invention's effect】
As described above, since the self-priming pump of the present invention is configured, the following advantageous effects can be obtained.
[0030]
In the self-priming pump according to claim 1, the flow rate returning from the discharge chamber to the suction chamber can be made small by generating a large loss resistance by the return flow rate regulating unit, and the return flow rate is small. Pump efficiency can be improved.
[0031]
In any of the self-priming pumps according to claims 2 to 4, a part of the fluid that is discharged from the impeller and flows through the impeller chamber or the discharge chamber causes a swirling flow to be generated in the fluid in the discharge chamber. The liquid separation action is performed, so that the self-priming operation can be quickly shifted to the pumping operation. Moreover, in the pumping operation, excellent pump efficiency can be obtained as in the first aspect.
[0032]
In the self-priming pump according to claim 5 or 6, since one end of the return communication pipe is opened near the bottom surface or near the bottom surface at a substantially axial center position of the cylindrical return flow regulating portion, the flow path flowing into the return communication pipe Loss resistance is large, and the pressure of the fluid flowing into the return communication pipe is low. Therefore, the return flow rate to the suction chamber is small, and the pump efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is an overall piping diagram of a first embodiment in which a self-priming pump of the present invention is applied to both suction centrifugal pumps.
2 is a partially cutaway longitudinal sectional view taken along a plane orthogonal to the pump axis of the self-priming pump of FIG. 1. FIG.
3 is a longitudinal sectional view cut along a plane including a pump shaft of the self-priming pump of FIG. 1. FIG.
4 is an end view taken along the line AA in FIG. 2;
FIG. 5 is a cross-sectional view of the vicinity of the discharge chamber of FIG.
6 is a partial view taken in the direction of arrow C in FIG.
FIG. 7 is a longitudinal sectional view for explaining the operation of a return flow rate restricting portion.
FIG. 8 is a diagram showing a tendency of a return flow rate with respect to an inflow pressure between the self-priming pump of the present invention and a conventional example.
FIG. 9 is a partially cutaway longitudinal sectional view taken along a plane orthogonal to the pump shaft of a second embodiment of the self-priming pump of the present invention.
10 is a longitudinal sectional view taken along a plane including the pump shaft of the self-priming pump of FIG. 9. FIG.
11 is an end view taken along the arrow D-D in the vicinity of the discharge chamber of FIG. 9;
FIG. 12 is an external view of a third embodiment in which the self-priming pump of the present invention is applied to a single suction centrifugal pump.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pump casing 14 Suction curved pipe 16 Pumping pipe 18 Suction water tank 20 Check valve 22 Main on-off valve 24 Discharge pipe 26 Return flow control part 28 Pump shaft 30 Impeller 32 Impeller chamber 34 Discharge chamber 36 Outlet port 38 Inlet port 40 Communication Pipe 42 Outlet 44 Inlet communication pipe 46 Inlet port 48 Holes 50 and 66 Return communication pipe 52 Suction chamber 60 Partition wall 62 Inflow chamber 64 Communication hole

Claims

In the self-priming pump that performs gas-liquid separation by swirling the fluid in the discharge pipe of the pump casing, an outlet in a substantially tangential direction in the swirling direction of the fluid is opened in the wall of the discharge pipe. A cylindrical return flow rate restricting portion having an axial direction as a substantially vertical direction is provided outside, a substantially tangential inlet is opened on the side wall of the return flow restricting portion, and the outlet and the inlet are connected by an inflow communication pipe. One end of the return communication pipe is opened at the cylindrical substantially axial center position of the return flow restricting portion, and the other end of the return communication pipe is opened to the suction chamber of the pump casing. Self-priming pump.

A part of the fluid discharged from the impeller chamber of the pump casing to the discharge chamber is caused to flow in a substantially tangential direction into the discharge chamber having a substantially circular inner shape in a cross section perpendicular to the flow direction, thereby rotating the fluid in the discharge chamber. A substantially tangential outlet in the swirling direction of the fluid is opened in the wall of the discharge chamber downstream of the position where the fluid flows in a substantially tangential direction, and the substantially vertical direction is axially outside the pump casing. A cylindrical return flow rate restricting portion is provided, a substantially tangential inflow port is opened in a side wall of the return flow restricting portion, and the outflow port and the inflow port are communicated with an inflow communication pipe. A self-priming pump characterized in that one end of the return communication pipe is opened at the cylindrical substantially axial position of the portion, and the other end of the return communication pipe is opened in the suction chamber of the pump casing.

3. The self-priming pump according to claim 2, wherein a discharge port is opened in a substantially tangential direction to a wall of the discharge chamber or the impeller chamber in a direction orthogonal to a rotation axis of the impeller, and the downstream side of the discharge port A self-priming pump characterized in that an inlet is opened in a substantially tangential direction in a cross section perpendicular to the flow direction on the wall of the discharge chamber, and the outlet and the inlet are connected by a communication pipe.

3. The self-priming pump according to claim 2, wherein a partition wall is provided along the flow path direction so as to divide the flow path in the impeller chamber or the discharge chamber to form an inflow chamber into which a part of fluid flows. In addition, the inflow chamber is adjacent to the discharge chamber by the partition wall, and a communication hole that opens in a substantially tangential direction in the cross section perpendicular to the flow direction is formed in the partition wall. A self-priming pump characterized by being configured.

5. The self-priming pump according to claim 1, wherein a hole is formed in a bottom surface of the return flow restricting portion at a substantially cylindrical axial center, and one end of the return communication pipe is communicated with the hole. A self-priming pump characterized by comprising

5. The self-priming pump according to claim 1, wherein one end of the return communication pipe is opened near a bottom surface of a substantially cylindrical axial center position of the return flow restricting portion. Self-priming pump.

The self-priming pump according to any one of claims 1 to 6, wherein the pump casing is a double suction type, the return communication pipe is branched so as to be two other ends, and the two other ends are respectively A self-priming pump characterized by being configured to open to a suction chamber.