JPS5832996A - Pump unit number switching operation method - Google Patents

Pump unit number switching operation method

Info

Publication number
JPS5832996A
JPS5832996A JP13312281A JP13312281A JPS5832996A JP S5832996 A JPS5832996 A JP S5832996A JP 13312281 A JP13312281 A JP 13312281A JP 13312281 A JP13312281 A JP 13312281A JP S5832996 A JPS5832996 A JP S5832996A
Authority
JP
Japan
Prior art keywords
pump
flow rate
head
additional pump
pumps
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
Application number
JP13312281A
Other languages
Japanese (ja)
Inventor
Hideo Murakami
秀夫 村上
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kubota Corp
Original Assignee
Kubota Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kubota Corp filed Critical Kubota Corp
Priority to JP13312281A priority Critical patent/JPS5832996A/en
Publication of JPS5832996A publication Critical patent/JPS5832996A/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
    • F04D15/02—Stopping of pumps, or operating valves, on occurrence of unwanted conditions
    • F04D15/029—Stopping of pumps, or operating valves, on occurrence of unwanted conditions for pumps operating in parallel

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Non-Positive-Displacement Pumps (AREA)
  • Control Of Positive-Displacement Pumps (AREA)

Abstract

PURPOSE:To obviate cavitation in a pump, by detecting a pump head and comparing the critical flow which may jnduce cavitation at said detected head with the actually detected flow whereby giving a start command to an additional pump, it necessary. CONSTITUTION:Detecting a pump head of the pump in operation and comparing the limit flow Qi inducing a cavitation at the detected pump head with an actually detected flow Q, and if the result of comparison satisfies Q1<=Q, a start command is given to an additional pump whereby switching the number of pump units can be thus carried out. Also detecting the total head of pumps in parallel operation and comparing the flow Q2 for stopping addition of pump line at the detected head with the actually detected flow Q, and it the result of comparison satisfies Q2>=Q, a stop command is given to the additional pump whereby switching the number of pump units can be thus achieved in the similar way.

Description

【発明の詳細な説明】 本発明は、たとえば網の目の如くに管路をはりめぐらせ
てなる不特定多数のシステムカーブプを有する送水路に
おける複数台ポンプの台数切替運転方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for switching the number of pumps in a water supply channel having an unspecified number of system curves, such as a network of pipes.

従来、この種の運転方法として、送水管路に、特定のシ
ステムカーブを設定し、流量が１台目のポンプにキャビ
テーションが発生する流量に増加すると２台目のポンプ
を起動し、また、２台目のポンプを起動した後、流量が
１台のポンプで対応できる流量に減少すると２台目のポ
ンプを停止させるというように、流量を検知してポンプ
の台数切替を行う方法がとられていた。Conventionally, this type of operation method involves setting a specific system curve in the water pipeline, and when the flow rate increases to a level at which cavitation occurs in the first pump, the second pump is started; After starting the first pump, when the flow rate decreases to a level that can be handled by one pump, the second pump is stopped, and so on, the number of pumps is switched by detecting the flow rate. Ta.

この方法では、送水系の想定したシステムカーブより揚
程が低いシステムカーブになるとき（たとえば予定外の
水量を使う場合）には、特定のシステムカーブを元にし
て、ポンプ台数の切替を行なう流量値を設定しているの
で、ポンプのキャビテーションを防止できないという問
題があった０本発明は上述した実情に鑑みなされたもの
で、その目的とするところは、システムカーフ゛がどの
ように変化してもポンプのキャビテーションを防専でき
るようにしたポンプの台数切替運転方法を提供しようと
するものである。In this method, when the system curve has a lower head than the assumed system curve for the water supply system (for example, when using an unplanned amount of water), the flow rate value at which the number of pumps is switched is determined based on a specific system curve. The present invention was made in view of the above-mentioned circumstances, and its purpose is to prevent the pump from cavitating no matter how the system curve changes. The purpose of this invention is to provide a method for switching the number of pumps that can prevent cavitation.

以下、本発明を図面を用いて説明する。Hereinafter, the present invention will be explained using the drawings.

図面には、１金目ポンプを回転数制御により５０％回転
数から１００％回転数まで運転制御するとともに、この
１金目ポンプがキャビテーションの限界に至った段階で
、２白目ポンプを追加起動し、１台目および２白目ポン
プを回転数制御により５０％回転数から１００％回転数
まで運転制御し、かつ流量が減じて２白目ポンプの運転
が不要になった段階でその２白目ポンプを停止するのに
本発明方法を適用した例が示されている。The drawing shows that the first pump is controlled to operate from 50% to 100% rotation speed, and when the first pump reaches its cavitation limit, the second pewter pump is additionally activated. Control the operation of the second and second pewter pumps from 50% to 100% rotation speed by controlling the rotation speed, and stop the second pewter pump when the flow rate decreases and the operation of the second pewter pump becomes unnecessary. An example in which the method of the present invention is applied is shown.

そして、この図面は、流量Ｑを横軸にとり、全揚程Ｐを
縦軸にとシ、流量Ｑの、、変化に対する全揚程Ｐの関係
を実線で示している。この線図中、Ａは、１金目ポンプ
の５０％回転数による揚程特性を示し、Ｂは、１金目ポ
ンプの１００％回転数による揚程特性を示し、また、Ｃ
は、１金目ポンプと２白目ポンプの５０％回転数による
合成揚程特性を示し、Ｄは１金目ポンプと２白目ポンプ
の】００％回転数による合成揚程特性を示している。In this drawing, the horizontal axis represents the flow rate Q, and the vertical axis represents the total head P, and the relationship between the total head P and the change in the flow rate Q is shown by a solid line. In this diagram, A shows the head characteristic at 50% rotation speed of the first gold pump, B shows the head characteristic at 100% rotation speed of the first gold pump, and C
shows the composite head characteristic at 50% rotation speed of the first gold pump and the second white pump, and D shows the composite head characteristic at ]00% rotation speed of the first gold pump and the second white pump.

そして、本発明方法は、この全揚程Ｐ−流量Ｑ線図上に
おいて、まず、１金目ポンプのキャビテーションを起こ
す限界位置に追加ポンプ起動線Ｅを設定し、この追加ポ
ンプ起動線Ｅに対応した流量Ｑ１を演算する関数（全揚
程Ｐ１の関数）Ｑ１＝チ（Ｐ＋）としてコンピューター
に〜記憶させておく。そして、１金目ポンプが単独運転
している場合、その運転時の実際のポンプ揚程Ｐ１と吐
出流量Ｑとをコンピューターにインプットし、そのイン
プットしたポンプ揚程Ｐ１に対応する追加ポンプ起動線
Ｃの流量Ｑ１を演算し、その演算された流量Ｑｌとイン
プットした実際の流量Ｑとを比較して、Ｑ１≦Ｑならば
２台目のポンプに起動指令を与えることができ、キャビ
テーションを発生させることなく並列運転に移行するこ
とができる。Then, in the method of the present invention, on this total head P - flow rate Q diagram, first, an additional pump starting line E is set at the limit position where cavitation of the first gold pump occurs, and the flow rate corresponding to this additional pump starting line E is set. A function for calculating Q1 (function of total head P1) is stored in the computer as Q1=Chi (P+). When the first pump is operating independently, input the actual pump head P1 and discharge flow rate Q during its operation into the computer, and then input the flow rate Q1 of the additional pump activation line C corresponding to the input pump head P1. is calculated, and the calculated flow rate Ql is compared with the input actual flow rate Q. If Q1≦Q, a start command can be given to the second pump, allowing parallel operation without causing cavitation. can be moved to.

また、全揚程Ｐ−流量Ｑ線図上において、前記追加ポン
プ起動線Ｅより低流量側の所定位置に２白目ポンプを停
止させる追加ポンプ停止線Ｆを設定し、この追加ポンプ
停止線Ｆに対応した流量Ｑ２を演算する関数（全揚程Ｐ
２の関数）　Ｑ！　＝　−ｆ（Ｐ２）としてコンピュー
ターに記憶させておく。そして、２白目ポンプが追加運
転された並列運転の場合、その運転時の実際のポンプ揚
程Ｐ２と吐出流量Ｑとをコンピューターにインプットし
、そのインプットしたポンプ揚程Ｐ２に対応する追加ポ
ンプ停止線Ｇの流量Ｑ２を演算し、その演算された流量
Ｑ２とインプットした実際の流量Ｑとを比較して、Ｑ２
＞　Ｑならば単独運転にすべく２台の内１台のポンプに
停止指令を与えることができ、能率よくポンプの切替が
可能になる。In addition, on the total head P-flow rate Q diagram, an additional pump stop line F is set to stop the second white pump at a predetermined position on the lower flow rate side than the additional pump start line E, and corresponds to this additional pump stop line F. A function to calculate the flow rate Q2 (total head P
2 function) Q! = -f(P2) and store it in the computer. In the case of parallel operation in which the second pewter pump is additionally operated, the actual pump head P2 and discharge flow rate Q during that operation are input into the computer, and the additional pump stop line G corresponding to the input pump head P2 is calculated. Calculate the flow rate Q2, compare the calculated flow rate Q2 with the input actual flow rate Q, and calculate Q2.
> Q, it is possible to give a stop command to one of the two pumps for independent operation, and it is possible to efficiently switch the pumps.

なお、上記説明において、２台あるポンプの１台を起動
したシ停止したりするポンプ台数切替について説明した
が、全揚程Ｐ−流量線図上において、１台目と２白目ポ
ンプの並列運転でキャビテーションを起こす限界位置に
設定した追加ポンプ起動線Ｇと、この追加ポンプ起動線
Ｇより低流量側の所定位置に設定した３金目ポンプを停
止させる追加ポンプ停止線Ｈとを加えてコンピューター
に記憶させておいて、３台のポンプを１台から３台まで
のポンプをキャビテーションを発生させることなく順次
に起動できるとともに、反対に順次に停止できる台数切
替であってもよい。また、３台以上の複数台のポンプに
上記方法を適用して台数切替が可能なのは勿論である。In addition, in the above explanation, we explained how to switch the number of pumps by starting and stopping one of the two pumps, but on the total head P - flow rate diagram, when the first and second pumps are operated in parallel, An additional pump start line G set at the limit position that causes cavitation and an additional pump stop line H that stops the third pump set at a predetermined position on the lower flow rate side than this additional pump start line G are added and stored in the computer. The number of pumps may be switched so that one to three pumps can be sequentially started without causing cavitation, and conversely, one to three pumps can be stopped sequentially. Furthermore, it goes without saying that the number of pumps can be changed by applying the above method to three or more pumps.

さらに、上記実施例において、１台目に起動するポンプ
を定速ポンプにして、２台目以降に起動する追加ポンプ
を回転数制御を行なうポンプとした構成であってもよい
。Furthermore, in the above embodiment, the first pump to be started may be a constant speed pump, and the second and subsequent pumps to be started may be pumps that perform rotational speed control.

以上説明してきたように、本発明によれば、従来のただ
単に、システムカーブがらキャビｆ　−ジョンが発生す
るであろう流量値のみで、ポンプの台数切替えをしてき
た方法に比べて、現運転しているポンプのポンプ揚程を
検出し、その検出値を有するキャビテーション発生限界
の流量Ｑ１と、実際に検出した流量Ｑとを比較すること
によって、Ｑｌ≦Ｑの場合、追加ポンプに起動指令を与
えてポンプ台数の切替えを行なうことができる。このた
め、たとえ送水管路のシステムカーブがどのように変化
してもポンプにキャビテーションを発生させることなく
ポンプ台数を増加することができるまた、並列運転して
いるポンプの揚程を検出し、その検出値を有する追加ポ
ンプ停止線の流量Ｑ２と、実際に検出した流量Ｑとを比
較することによって、Ｑ２≧−Ｑの場合、追加ポンプに
停止指令を与えてポンプ台数の切替を行かうことができ
る。このため、たとえ送水管路のシステムカーブがどの
様に変化しても支障なくポンプの台数削減ができる。As explained above, according to the present invention, compared to the conventional method of simply changing the number of pumps based on the flow rate value at which cavitation would occur based on the system curve, By detecting the pump head of the pump being detected and comparing the detected value with the flow rate Q1 at the cavitation generation limit and the actually detected flow rate Q, if Ql≦Q, a start command is given to the additional pump. The number of pumps can be changed by Therefore, no matter how the system curve of the water pipeline changes, the number of pumps can be increased without causing cavitation in the pumps.In addition, the head of pumps operating in parallel can be detected. By comparing the flow rate Q2 of the additional pump stop line that has a value with the actually detected flow rate Q, if Q2≧-Q, it is possible to switch the number of pumps by giving a stop command to the additional pump. . Therefore, the number of pumps can be reduced without any problem, no matter how the system curve of the water supply pipeline changes.

【図面の簡単な説明】[Brief explanation of the drawing]

図面は本発明の詳細な説明に用いる線図であ不〇特許出
願人　久保田鉄工株式会社 代理人　弁理士　鈴　江　孝　−The drawings are line diagrams used for detailed explanation of the present invention.Patent applicant: Kubota Iron Works Co., Ltd. Agent Patent attorney: Takashi Suzue −

Claims (1)

【特許請求の範囲】 全揚程？）−流量０線図上のキャビテーションを起こす
限界位置に設定される追加ポンプ起動線をコンピュータ
ーに記憶させ、その運転時のポンプの全揚程ぼ】）と実
際の流量（Ｑ）とをコンピューターにインプットし、そ
のインプットした運転時の全揚程のときの前記追加ポン
プ起動線上の流量（Ｑｌ）と実際の流量（Ｑ）とを比較
して（Ｑｌ）≦（Ｑ）ならば追加ポンプを起動し、かつ
全揚程（Ｐ）−流量Ｑ線図上の前記追加ポンプ起動線よ
り低流量側の所定位置に設定される追加ポンプ停止線を
コンピューターに記憶させ、その運転時のポンプの全揚
程（Ｐ２）と実際の流量Ｑとをコンビユニターにインプ
ットし、そのインプットした運転時の全揚程のときの前
記追加ポンプ停止線上の流量（Ｑ２〉 ）と実際の流量０とを比較して（Ｑ２）　−（Ｑ）なら
ば前記追加ポンプを停止させることを特徴とするポンプ
の台数切替運転方法０[Claims] Total lift? ) - Store in the computer the additional pump activation line set at the limit position that causes cavitation on the zero flow diagram, and input the total head of the pump during operation ( ) and the actual flow rate (Q) into the computer. Then, compare the input flow rate (Ql) on the additional pump starting line at the full head during operation with the actual flow rate (Q), and if (Ql)≦(Q), start the additional pump, Also, store in the computer an additional pump stop line that is set at a predetermined position on the lower flow rate side than the additional pump start line on the total head (P) - flow rate Q diagram, and calculate the total head (P2) of the pump during its operation. and the actual flow rate Q are input into the combination unit, and the input flow rate (Q2〉) on the additional pump stop line at the full head during operation is compared with the actual flow rate 0 (Q2) - (Q ), then the pump number switching operation method 0 is characterized by stopping the additional pump.
JP13312281A 1981-08-24 1981-08-24 Pump unit number switching operation method Pending JPS5832996A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13312281A JPS5832996A (en) 1981-08-24 1981-08-24 Pump unit number switching operation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13312281A JPS5832996A (en) 1981-08-24 1981-08-24 Pump unit number switching operation method

Publications (1)

Publication Number Publication Date
JPS5832996A true JPS5832996A (en) 1983-02-26

Family

ID=15097297

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13312281A Pending JPS5832996A (en) 1981-08-24 1981-08-24 Pump unit number switching operation method

Country Status (1)

Country Link
JP (1) JPS5832996A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5457201A (en) * 1977-10-14 1979-05-08 Toyo Electric Mfg Co Ltd Device ofr controlling number of pumps

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5457201A (en) * 1977-10-14 1979-05-08 Toyo Electric Mfg Co Ltd Device ofr controlling number of pumps

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