JPH04272496A - Pump operating method for a plurality of pump using - Google Patents
Pump operating method for a plurality of pump usingInfo
- Publication number
- JPH04272496A JPH04272496A JP3277691A JP3277691A JPH04272496A JP H04272496 A JPH04272496 A JP H04272496A JP 3277691 A JP3277691 A JP 3277691A JP 3277691 A JP3277691 A JP 3277691A JP H04272496 A JPH04272496 A JP H04272496A
- Authority
- JP
- Japan
- Prior art keywords
- pumps
- pump
- water level
- water
- drainage operation
- 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.)
- Granted
Links
- 238000011017 operating method Methods 0.000 title description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 126
- 238000009434 installation Methods 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 10
- 238000011144 upstream manufacturing Methods 0.000 claims description 9
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 238000005086 pumping Methods 0.000 abstract 1
- 230000003252 repetitive effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 8
- 238000010521 absorption reaction Methods 0.000 description 1
- -1 and h<V2/ In 2g Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Landscapes
- Control Of Non-Positive-Displacement Pumps (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、複数台ポンプの運転方
法に係り、特に水路に設置されている排水機場の吸水井
または雨水ポンプ設備などにおいて行う複数待機運転ポ
ンプの運転に好適な運転方法に関する。[Industrial Application Field] The present invention relates to a method of operating a plurality of pumps, and is particularly suitable for operating a plurality of standby pumps in a water intake well of a drainage pump station installed in a waterway or in a rainwater pump facility. Regarding.
【０００２】0002
【従来の技術】排水機場の吸水井に流入してきた水は、
吸水井に配置されている複数台のポンプの運転によって
排水される場合が多い。この場合、複数台のポンプは、
一般に、全て同じ型式のものが用いられ、しかも各ポン
プの羽根車を全て同じ高さに設定して吸水井に設置して
いる。また羽根車上流側の吸込みケーシング内に連通す
る大気開放吸気管を設けたポンプでは、各ポンプの羽根
車をそれぞれ同じ高さに設定するとともに、吸込みケー
シング内に連通する吸気管の取付け位置もそれぞれ同じ
高さに設定して、排水運転可能最低水位を統一させた状
態で運転を行っている。なお、排水運転可能最低水位と
は、吸気管より吸気されることなく所定の吐出量（１０
０％Ｑ）での排水運転を行うことのできる最低水位であ
る。[Prior art] Water flowing into the water intake well of a drainage pump station is
Water is often drained by operating multiple pumps placed in a water intake well. In this case, multiple pumps are
Generally, all pumps are of the same type, and the impellers of each pump are all set at the same height and installed in the water intake well. In addition, for pumps that have an air-opening intake pipe that communicates with the suction casing upstream of the impeller, the impellers of each pump should be set at the same height, and the installation positions of the intake pipes that communicate with the suction casing should also be set at different locations. The drains are set at the same height and are operated with a unified minimum water level for drainage operation. Note that the minimum water level that allows drainage operation is the specified discharge amount (10
This is the lowest water level at which drainage operation can be performed at 0% Q).
【０００３】このように、同じ型式で、しかも羽根車の
位置および吸気管の取付け位置を全て同じ高さに統一し
て複数台ポンプを設置した運転方法では、ポンプ同士の
互換性を確保できるから、経年劣化または万一故障が発
生した場合などにおいて、補給しなければならない交換
部品の管理が容易になる。しかし、吸水井の水位が前記
排水運転可能最低水位よりも低く、全てのポンプが気中
運転（先行待機運転）している間に、水位が上昇して排
水運転可能最低水位に到達すると、この時点で全ポンプ
の一斉排水運転が開始されることになる。この場合、全
ポンプの排水総量の方が吸水井への流入水量よりも十分
に多いと、水位が急激に気中運転水位に低下して、再度
気中運転に切替えられることになる。つまり、短い周期
で気中運転と排水運転が繰り返される場合もあり、ポン
プの寿命を短くする一因になる問題点がある。[0003] In this way, the operation method in which multiple pumps of the same type are installed with the impeller positions and intake pipes installed at the same height can ensure compatibility between the pumps. This makes it easier to manage replacement parts that must be supplied in the event of deterioration over time or a failure. However, if the water level in the water intake well is lower than the minimum water level that allows drainage operation, and while all pumps are in submerged operation (advance standby operation), the water level rises and reaches the minimum water level that allows drainage operation. At this point, simultaneous drainage operation of all pumps will begin. In this case, if the total amount of water discharged by all the pumps is sufficiently larger than the amount of water flowing into the water intake well, the water level will suddenly drop to the submerged operation water level, and the pump will be switched to submerged operation again. In other words, submerged operation and drainage operation may be repeated in short cycles, which is a problem that shortens the life of the pump.
【０００４】このような問題を回避する手段として、長
さ（高さ）および羽根車の高さ位置が互いに異なる複数
台のポンプを使用して、ポンプ毎の排水運転可能最低水
位に高低差をもたせて運転する方法が考えられる。この
運転方法によれば、複数台のポンプの排水運転開始タイ
ミングに時間差をもたせて、水位の急激な低下を防止す
ることができるので気中運転と排水運転の繰り返し周期
を延長できる。しかし、このような運転方法では、ポン
プ同士の互換性が無くなるため、交換部品の管理を困難
にする欠点がある。[0004] As a means to avoid such problems, a plurality of pumps with different lengths (heights) and height positions of impellers are used to create a height difference in the minimum water level at which each pump can operate. One possible method is to lean on it while driving. According to this operating method, it is possible to prevent a sudden drop in the water level by providing a time lag in the start timing of the draining operation of the plurality of pumps, so that the repetition cycle of the submerged operation and the draining operation can be extended. However, this operating method has the disadvantage that the pumps are not compatible with each other, making it difficult to manage replacement parts.
【０００５】[0005]
【発明が解決しようとする課題】解決しようとする問題
点は、ポンプ毎の排水運転可能最低水位に高低差を付け
て、排水運転開始タイミングに時間差をもたせ、吸水井
の水位が急激に低下するのを防止して、気中運転と排水
運転の繰り返し周期を延長させると、ポンプ同士の互換
性が無くなって交換部品の管理を困難にし、逆にポンプ
同士の互換性を確保して、交換部品の管理を容易にする
と吸水井の水位が急激に低下して、気中運転と排水運転
の繰り返し周期が短縮されてポンプの寿命を短くする点
である。[Problem to be solved by the invention] The problem to be solved is that the minimum water level at which drainage operation is possible for each pump is made to have a difference in height, and there is a time difference in the timing of starting drainage operation, which causes the water level in the water intake well to drop rapidly. If we prevent this and extend the repetition cycle of submersible operation and drainage operation, pumps will become incompatible with each other, making it difficult to manage replacement parts. If this management is made easier, the water level in the water suction well will drop rapidly, and the repetition cycle of submerged operation and drainage operation will be shortened, shortening the life of the pump.
【０００６】[0006]
【課題を解決するための手段】請求項１の発明は、排水
運転可能最低水位は吸気管の取付け位置から水面までの
高さｈと、吸込みケーシングに吸い込まれる水における
吸気管取付け位置の吸込み速度水頭Ｖ２／ ２ｇが、ｈ
＝Ｖ２／ ２ｇに釣り合うことによって決定され、ｈ＞
Ｖ２／ ２ｇでは当然１００％排水となり、ｈ＜Ｖ２／
２ｇでは吸気管から吸込みケーシング内に空気が吸い
込まれ、吸い込まれる空気量に応じて、いいかえれば水
位の低下度に応じて気水混合運転または気中運転される
点に着目して、羽根車上流側の吸込みケーシング内に連
通して取付けられている大気開放吸気管から吸気できる
ように構成した複数台のポンプの羽根車の位置をそれぞ
れ同じ高さに設定して吸水井に設置し、これらポンプそ
れぞれの前記吸気管の吸込みケーシング内に連通する取
付け位置をポンプ毎に上下方向に互いに変位して設定し
、ポンプ毎の排水運転可能最低水位に高低差を付けて排
水運転開始タイミングに時間差をもたせて運転するよう
にしたことを特徴とし、吸水井の水位が急激に低下する
のを防止し、気中運転と排水運転の繰り返し周期を延長
させてポンプの延命化を図り、かつポンプ同士の互換性
を確保して、交換部品の管理を容易にする目的を実現し
た。[Means for Solving the Problems] The invention as claimed in claim 1 provides that the lowest water level at which drainage operation is possible is determined by the height h from the installation position of the intake pipe to the water surface and the suction speed of water sucked into the suction casing at the installation position of the intake pipe. The water head V2/2g is h
= V2/ determined by balancing 2g, h>
Naturally, at V2/ 2g, it becomes 100% waste water, and h<V2/
In 2g, air is sucked into the suction casing from the intake pipe, and depending on the amount of air sucked in, in other words, depending on the degree of drop in the water level, air-water mixing operation or air-water operation is performed. The impellers of multiple pumps configured so that air can be taken in from the air-opening intake pipes installed in communication with the side suction casing are set at the same height, and installed in the water intake well. The installation positions of each of the intake pipes communicating with the suction casing are set so as to be displaced from each other in the vertical direction for each pump, and the lowest water level at which drainage operation is possible for each pump is set to have a height difference, thereby creating a time difference in the timing of starting drainage operation. The pump is characterized by being operated in a continuous manner, preventing the water level in the water intake well from dropping rapidly, extending the cycle of repeating submerged operation and drainage operation, extending the life of the pump, and making the pumps compatible with each other. This has achieved the purpose of ensuring safety and facilitating the management of replacement parts.
【０００７】また、請求項２の発明は、排水運転可能最
低水位は吸気管の取付け位置から水面までの高さｈと、
吸込みケーシングに吸い込まれる水における吸気管取付
け位置の吸込み速度水頭Ｖ２／ ２ｇが、ｈ＝Ｖ２／２
ｇに釣り合うことによって決定され、ｈ＞Ｖ２／ ２ｇ
では当然１００％排水となり、ｈ＜Ｖ２／ ２ｇでは吸
気管から吸込みケーシング内に空気が吸い込まれ、吸い
込まれる空気量に応じて、いいかえれば水位の低下度に
応じて気水混合運転または気中運転される点に着目して
、羽根車上流側の吸込みケーシング内に連通して取付け
られている大気開放吸気管から吸気できるように構成し
た複数台のポンプの羽根車の位置をそれぞれ同じ高さに
設定して吸水井に設置し、これらポンプそれぞれの前記
吸気管の吸込みケーシング内に連通する取付け位置を前
記吸込みケーシング内に張出し形成した抵抗体と水の旋
回方向によって決定される円周方向の圧力分布に基づい
てポンプ毎に円周方向に互いに変位して設定し、この取
付け位置の変位に伴って変化する負圧度に応じてポンプ
毎の排水運転可能最低水位に高低差を付けて排水運転開
始タイミングに時間差をもたせて運転するようにしたこ
とを特徴とし、吸水井の水位が急激に低下するのを防止
し、気中運転と排水運転の繰り返し周期を延長させてポ
ンプの延命化を図り、かつポンプ同士の互換性を確保し
て、交換部品の管理を容易にする目的を実現した。[0007] Furthermore, the invention of claim 2 provides that the lowest water level at which drainage operation is possible is the height h from the installation position of the intake pipe to the water surface;
The suction velocity head V2/2g of water sucked into the suction casing at the intake pipe installation position is h=V2/2
Determined by balancing g, h>V2/2g
Naturally, this will result in 100% drainage, but if h<V2/2g, air will be sucked into the suction casing from the intake pipe, and depending on the amount of air sucked in, or in other words, depending on the degree of drop in the water level, air-water mixing operation or air-water operation will be performed. Focusing on the point that The pressure in the circumferential direction is determined by the resistance body formed by projecting into the suction casing and the swirling direction of the water. Each pump is set to be displaced from each other in the circumferential direction based on the distribution, and drainage operation is performed with height differences in the lowest water level that can be operated for each pump depending on the degree of negative pressure that changes with the displacement of this mounting position. The pump is characterized by a time lag in the start timing of the pump, which prevents the water level in the suction well from dropping rapidly and extends the life of the pump by extending the repetition cycle of submerged and draining operations. , and ensured compatibility between pumps to facilitate the management of replacement parts.
【０００８】さらに、請求項３の発明は、羽根車上流側
の吸込みケーシング内に連通して取付けられている大気
開放吸気管から吸気できるように構成した複数台のポン
プの羽根車の位置をそれぞれ同じ高さに設定して吸水井
に設置し、これらポンプそれぞれの前記吸気管に通路面
積差をもたせ、この通路面積差にともなって変化する吸
気抵抗に応じてポンプ毎の排水運転可能最低水位に高低
差を付けて、排水運転開始タイミングに時間差をもたせ
て運転するようにしたことを特徴とし、吸水井の水位が
急激に低下するのを防止し、気中運転と排水運転の繰り
返し周期を延長させてポンプの延命化を図り、かつポン
プ同士の互換性を確保して、交換部品の管理を容易にす
る目的を実現した。Furthermore, the invention according to claim 3 adjusts the position of the impeller of each of the plurality of pumps configured so that air can be taken in from the air-opening intake pipe installed in communication with the suction casing on the upstream side of the impeller. These pumps are set at the same height and installed in a water intake well, and the intake pipes of each of these pumps have a difference in passage area, and the lowest water level at which drainage operation is possible for each pump is adjusted according to the intake resistance that changes due to the difference in passage area. The feature is that the operation is performed with a difference in height and a time difference in the start timing of drainage operation, which prevents the water level of the water intake well from dropping rapidly and extends the repetition cycle of submerged operation and drainage operation. This achieved the goal of extending the life of the pump, ensuring compatibility between pumps, and facilitating the management of replacement parts.
【０００９】[0009]
【作用】請求項１の発明によれば、内径が一様でなく、
上側から下側に向けてラッパ状に漸次拡径する吸込みケ
ーシングを使用すると、吸気管の取付け位置によって吸
込み速度水頭は変化する。つまり吸気管の取付け位置が
内径の小さくなる上位に移行するほど、吸込み速度水頭
は大きくなる。吸込み速度水頭に釣り合って排水運転可
能最低水位を決定する前記ｈの値は、吸気管の取付け位
置の変位に伴って変化する吸込み速度水頭に応じて変動
し、排水運転可能最低水位を変動させることになる。そ
のためにポンプ毎の排水運転可能最低水位に高低差が付
いて排水運転開始タイミングに時間差をもたせることが
できる。また内径が一様に形成されている吸込みケーシ
ングを使用すると、吸気管の取付け位置にかかわらず吸
込み速度水頭は一定である。したがって吸込み速度水頭
に釣り合って排水運転可能最低水位を決定する前記ｈの
値は変動しないが、吸気管の取付け位置の高さ方向の変
位に伴って排水運転可能最低水位は変動することになる
。そのためにポンプ毎の排水運転可能最低水位に高低差
が付いて排水運転開始タイミングに時間差をもたせるこ
とができる。[Operation] According to the invention of claim 1, the inner diameter is not uniform;
When a suction casing whose diameter gradually expands in a trumpet shape from the top to the bottom is used, the suction velocity head changes depending on the installation position of the intake pipe. In other words, the higher the installation position of the intake pipe is, where the inner diameter is smaller, the greater the suction velocity head becomes. The value of h, which determines the minimum water level at which drainage operation is possible in proportion to the suction speed head, varies in accordance with the suction speed head, which changes with the displacement of the installation position of the intake pipe, thereby varying the minimum water level at which drainage operation is possible. become. For this reason, the minimum water level at which drainage operation is possible for each pump has a difference in height, and it is possible to provide a time difference in the timing of starting drainage operation. Furthermore, if a suction casing with a uniform inner diameter is used, the suction velocity head will be constant regardless of the installation position of the intake pipe. Therefore, the value of h, which determines the minimum water level at which drainage operation is possible in proportion to the suction speed water head, does not change, but the minimum water level at which drainage operation is possible varies as the installation position of the intake pipe is displaced in the height direction. For this reason, the minimum water level at which drainage operation is possible for each pump has a difference in height, and it is possible to provide a time difference in the timing of starting drainage operation.
【００１０】請求項２の発明によれば、吸込みケーシン
グの内面に近い領域で一方向に旋回する水の圧力分布は
、抵抗体の形成部位における旋回方向の直下流位置での
負圧度が最も大きく、旋回方向の直上流位置での負圧度
が最も小さくなる。吸込み速度水頭に釣り合って排水運
転可能最低水位を決定する前記ｈと同じ高さであるべき
吸気管内の水位は、吸気管の取付け位置の変位に伴って
変化する負圧度に応じて変動し、排水運転可能最低水位
を変動させることになる。そのためにポンプ毎の排水運
転可能最低水位に高低差が付いて排水運転開始タイミン
グに時間差をもたせることができる。According to the second aspect of the invention, the pressure distribution of the water swirling in one direction in the area near the inner surface of the suction casing has the highest degree of negative pressure at the position immediately downstream of the swirling direction in the region where the resistor is formed. The degree of negative pressure is the lowest at the position immediately upstream in the turning direction. The water level in the intake pipe, which should be at the same height as the above-mentioned h, which determines the minimum water level at which drainage operation is possible in proportion to the suction speed water head, fluctuates in accordance with the degree of negative pressure that changes with the displacement of the installation position of the intake pipe, This will change the minimum water level for drainage operation. For this reason, the minimum water level at which drainage operation is possible for each pump has a difference in height, and it is possible to provide a time difference in the timing of starting drainage operation.
【００１１】請求項３の発明によれば、吸気管の空気の
流入量は、吸気管の通路面積の大きさに伴って変化する
吸気抵抗に応じて変動し、排水運転可能最低水位を変動
させる。いいかえれば吸気抵抗が小さいほど排水運転可
能最低水位を高くし、吸気抵抗が大きいほど排水運転可
能最低水位を低くしてポンプ毎の排水運転可能最低水位
に高低差を付けることになる。したがって排水運転開始
タイミングに時間差をもたせることができる。According to the third aspect of the present invention, the amount of air flowing into the intake pipe changes in accordance with the intake resistance that changes with the size of the passage area of the intake pipe, thereby changing the minimum water level at which drainage operation is possible. . In other words, the lower the intake resistance, the higher the minimum water level that allows drainage operation, and the larger the intake resistance, the lower the minimum water level that allows drainage operation, thereby creating a height difference between the minimum water levels that allow drainage operation for each pump. Therefore, it is possible to provide a time difference in the timing of starting the drainage operation.
【００１２】0012
【実施例】以下、本発明の実施例を図面に基づいて説明
する。図１は、請求項１の発明の一実施例を適用した立
軸ポンプの概略構成図を示し、排水機場のポンプ吸水井
１には、同じ型式の複数台（例えば２台）の立軸ポンプ
２Ａ，２Ｂが羽根車２ａ，２ｂの位置をそれぞれ同じ高
さに設定して設置されている。羽根車２ａ，２ｂの上流
側には、上側から下側に向けてラッパ状に漸次拡径する
形状の吸込みケーシング３Ａ，３Ｂが取付けられている
。立軸ポンプ２Ａにおける吸込みケーシング３Ａの内部
に連通して、入口を常時大気に開口している大気開放吸
気管４Ａの出口が取付けられている。また立軸ポンプ２
Ｂにおける吸込みケーシング３Ｂの内部に連通して、入
口を常時大気に開口している大気開放吸気管４Ｂの出口
が取付けられている。大気開放吸気管４Ａの出口の取付
け位置は羽根車２ａの入口に近い高い位置、つまり吸込
み速度水頭の大きくなる位置に設定され、大気開放吸気
管４Ｂの出口の取付け位置は吸込みケーシング３Ｂの吸
込口に近い吸込み速度水頭の小さくなる位置に設定され
ており、両大気開放吸気管４Ａ，４Ｂの通路面積は互い
に等しく設定されている。Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 shows a schematic configuration diagram of a vertical shaft pump to which an embodiment of the invention of claim 1 is applied. 2B is installed with the impellers 2a and 2b set at the same height. Suction casings 3A, 3B each having a shape whose diameter gradually increases in a trumpet shape from the upper side toward the lower side are attached to the upstream side of the impellers 2a, 2b. An outlet of an air-opening intake pipe 4A, which communicates with the interior of the suction casing 3A of the vertical shaft pump 2A, and whose inlet is always open to the atmosphere, is attached. Also, vertical shaft pump 2
An outlet of an air-opening intake pipe 4B that communicates with the inside of the suction casing 3B at B and whose inlet is always open to the atmosphere is attached. The mounting position of the outlet of the atmosphere-opening intake pipe 4A is set at a high position close to the inlet of the impeller 2a, that is, the position where the suction velocity head becomes large, and the mounting position of the outlet of the atmosphere-opening intake pipe 4B is set at the suction port of the suction casing 3B. The suction speed head is set at a position close to , and the passage areas of both air-open intake pipes 4A and 4B are set to be equal to each other.
【００１３】つぎに作動を説明する。吸込みケーシング
３Ａ，３Ｂは上側から下側に向けてラッパ状に漸次拡径
しているので、水の流速は上側に移行するほど速くなる
。したがって吸気管４Ａの取付け位置における吸込み速
度水頭は吸気管４Ｂの取付け位置における吸込み速度水
頭よりも大きくなる。吸込み速度水頭に釣り合って排水
運転可能最低水位ＷＬ１，ＷＬ２を決定するｈ１，ｈ２
の値は、吸気管４Ａ，４Ｂの取付け位置の変位に伴って
変動し、ｈ１をｈ２よりも大きくして排水運転可能最低
水位ＷＬ１をＷＬ２よりも高くすることになる。そのた
めに水位上昇時の排水運転開始タイミングは、立軸ポン
プ２Ｂの方が立軸ポンプ２Ａよりも早くなる。なお水位
が排水運転可能最低水位ＷＬ１，ＷＬ２よりも上位から
下降してくる場合では、立軸ポンプ２Ａの方が立軸ポン
プ２Ｂよりも早く排水運転を完了する。前述のように排
水運転開始タイミングに時間差をもたせることによって
、同じタイミングで複数台ポンプの排水運転を開始させ
ていた従来の運転方法のような水位の急激な低下が確実
に防止され、気中運転と排水運転の繰り返し周期を延長
してポンプの延命化に寄与することができる。またポン
プ同士の互換性を確保して、交換部品の管理を容易する
。Next, the operation will be explained. Since the suction casings 3A and 3B gradually expand in diameter in a trumpet shape from the upper side to the lower side, the flow rate of water becomes faster as it moves upward. Therefore, the suction velocity head at the attachment position of the intake pipe 4A is larger than the suction velocity head at the attachment position of the intake pipe 4B. h1, h2 to determine the lowest water level WL1, WL2 that allows drainage operation in proportion to the suction speed head
The value of changes with the displacement of the installation position of the intake pipes 4A, 4B, and h1 is made larger than h2 to make the lowest water level WL1 that allows drainage operation higher than WL2. Therefore, when the water level rises, the drainage operation starts earlier in the vertical shaft pump 2B than in the vertical shaft pump 2A. Note that when the water level falls from above the lowest water level WL1, WL2 at which drainage operation is possible, the vertical shaft pump 2A completes the drainage operation earlier than the vertical shaft pump 2B. As mentioned above, by providing a time lag in the start timing of drainage operations, the sudden drop in water level that would occur in the conventional operation method, where multiple pumps start draining operations at the same timing, is reliably prevented, making it possible to avoid submerged operation. This can contribute to extending the life of the pump by extending the repetition cycle of the drain operation. It also ensures compatibility between pumps and facilitates management of replacement parts.
【００１４】図２は、請求項１の発明の他の実施例を適
用した立軸ポンプの概略構成図を示し、排水機場のポン
プ吸水井１には、同じ型式の複数台（例えば２台）の立
軸ポンプ２Ａ，２Ｂが羽根車２ａ，２ｂの位置をそれぞ
れ同じ高さに設定して設置されている。羽根車２ａ，２
ｂの上流側には、内径が一様に形成されている吸込みケ
ーシング３Ａ，３Ｂを取付けている。立軸ポンプ２Ａに
おける吸込みケーシング３Ａの内部に連通して、入口を
常時大気に開口している大気開放吸気管４Ａの出口が取
付けられている。また立軸ポンプ２Ｂにおける吸込みケ
ーシング３Ｂの内部に連通して、入口を常時大気に開口
している大気開放吸気管４Ｂの出口が取付けられている
。大気開放吸気管４Ａの出口の取付け位置は羽根車２ａ
の入口に近い高い位置に設定され、大気開放吸気管４Ｂ
の出口の取付け位置は吸込みケーシング３Ｂの吸込口に
近い低い位置、つまり吸気管４Ａの取付け位置よりもΔ
ｈだけ低い位置に設定されており、両大気開放吸気管４
Ａ，４Ｂの通路面積は互いに等しく設定されている。FIG. 2 shows a schematic configuration diagram of a vertical shaft pump to which another embodiment of the invention of claim 1 is applied, and a plurality of pumps (for example, two pumps) of the same type are installed in the pump suction well 1 of the drainage pump station. Vertical shaft pumps 2A and 2B are installed with impellers 2a and 2b set at the same height, respectively. Impeller 2a, 2
Suction casings 3A and 3B each having a uniform inner diameter are attached to the upstream side of b. An outlet of an air-opening intake pipe 4A, which communicates with the interior of the suction casing 3A of the vertical shaft pump 2A, and whose inlet is always open to the atmosphere, is attached. Further, an outlet of an air-opening intake pipe 4B, which communicates with the interior of the suction casing 3B of the vertical shaft pump 2B and whose inlet is always open to the atmosphere, is attached. The installation position of the outlet of the air-opening intake pipe 4A is the impeller 2a.
The air intake pipe 4B is set at a high position near the inlet of the
The installation position of the outlet is at a lower position near the suction port of the suction casing 3B, that is, Δ is lower than the installation position of the intake pipe 4A.
It is set at a lower position by h, and both air-open intake pipes 4
The passage areas of A and 4B are set equal to each other.
【００１５】つぎに作動を説明する。吸込みケーシング
３Ａ，３Ｂの内径は一様に形成されているから、吸気管
４Ａ，４Ｂの取付け位置にかかわらず吸込み速度水頭は
一定である。したがって吸込み速度水頭に釣り合って排
水運転可能最低水位ＷＬ１，ＷＬ２を決定する前記ｈ１
，ｈ２の値も一定になるが、吸気管４Ａは吸気管４Ｂよ
りもΔｈだけ高い位置に設定して取付けられているから
、排水運転可能最低水位ＷＬ１はＷＬ２よりもΔｈだけ
高くなる。そのために水位上昇時の排水運転開始タイミ
ングは、立軸ポンプ２Ｂの方が立軸ポンプ２Ａよりも早
くなる。なお水位が排水運転可能最低水位ＷＬ１，ＷＬ
２よりも上位から下降してくる場合では、立軸ポンプ２
Ａの方が立軸ポンプ２Ｂよりも早く排水運転を完了する
。前述のように排水運転開始タイミングに時間差をもた
せることによって、同じタイミングで複数台ポンプの排
水運転を開始させていた従来の運転方法のような水位の
急激な低下が確実に防止され、気中運転と排水運転の繰
り返し周期を延長してポンプの延命化に寄与することが
できる。またポンプ同士の互換性を確保して、交換部品
の管理を容易する。Next, the operation will be explained. Since the inner diameters of the suction casings 3A and 3B are uniform, the suction velocity head is constant regardless of the mounting position of the suction pipes 4A and 4B. Therefore, the above-mentioned h1 determines the lowest water level WL1, WL2 that allows drainage operation in proportion to the suction speed head.
, h2 are also constant, but since the intake pipe 4A is installed at a position higher than the intake pipe 4B by Δh, the lowest water level WL1 that allows drainage operation is higher than WL2 by Δh. Therefore, when the water level rises, the drainage operation starts earlier in the vertical shaft pump 2B than in the vertical shaft pump 2A. In addition, the water level is the lowest water level that allows drainage operation WL1, WL
If the pump is coming down from a position higher than 2, use vertical shaft pump 2.
A completes the drainage operation sooner than the vertical shaft pump 2B. As mentioned above, by providing a time lag in the start timing of drainage operations, the sudden drop in water level that would occur in the conventional operation method, where multiple pumps start draining operations at the same timing, is reliably prevented, making it possible to avoid submerged operation. This can contribute to extending the life of the pump by extending the repetition cycle of the drain operation. It also ensures compatibility between pumps and facilitates management of replacement parts.
【００１６】図３ないし図５は、請求項２の発明の一実
施例を適用した立軸ポンプの概略構成図を示す。なお、
前記請求項１の発明の実施例と同一もしくは相当部分に
は同一符号を付して、詳しい説明は省略する。図３ない
し図５において、立軸ポンプ２Ａと立軸ポンプ２Ｂそれ
ぞれの吸込みケーシング３Ａ，３Ｂの内面には、径内方
向に張出すリブ状の抵抗体５が形成されている。吸気管
４Ａと吸気管４Ｂの出口の取付け位置は同じの高さに設
定され、かつ吸気管４Ａの出口を抵抗体５に接近した水
の旋回方向Ｒの直下流位置に設定し、吸気管４Ｂの出口
を抵抗体５に接近した水の旋回方向Ｒの直上流位置に設
定している。つまり、吸気管４Ａの出口を抵抗体５と水
の旋回方向Ｒによって決定される負圧度の最も大きい位
置に設定し、吸気管４Ｂの出口を抵抗体５と水の旋回方
向Ｒによって決定される負圧度の最も小さい位置に設定
している。FIGS. 3 to 5 show schematic configuration diagrams of a vertical shaft pump to which an embodiment of the invention of claim 2 is applied. In addition,
The same or equivalent parts as in the embodiment of the invention according to claim 1 are given the same reference numerals, and detailed description thereof will be omitted. In FIGS. 3 to 5, a rib-shaped resistor 5 extending radially inward is formed on the inner surface of the suction casings 3A and 3B of the vertical shaft pump 2A and the vertical shaft pump 2B, respectively. The installation positions of the outlets of the intake pipe 4A and the intake pipe 4B are set at the same height, and the outlet of the intake pipe 4A is set at a position directly downstream in the swirling direction R of the water approaching the resistor 5, The outlet of the resistor 5 is set at a position immediately upstream of the water approaching the resistor 5 in the swirling direction R. In other words, the outlet of the intake pipe 4A is set at the position where the degree of negative pressure is greatest determined by the resistor 5 and the water swirling direction R, and the outlet of the intake pipe 4B is set at the position determined by the resistor 5 and the water swirling direction R. It is set at the position where the degree of negative pressure is the lowest.
【００１７】つぎに作動を説明する。吸気管４Ａ，４Ｂ
の取付け位置は同じ高さに設定されているが、吸気管４
Ａは負圧度の大きい位置に設定して取付けられ、一方、
吸気管４Ｂは負圧度の小さい位置に設定して取付けられ
ているから、この負圧度の差をΔｈ１とすると、排水運
転可能最低水位ＷＬ１，ＷＬ２を決定するｈ１，ｈ２の
値は、ｈ２の方がｈ１よりもΔｈ１だけ低下し、排水運
転可能最低水位ＷＬ１をＷＬ２よりもΔｈ１だけ高くす
る。そのために水位上昇時の排水運転開始タイミングは
、立軸ポンプ２Ｂの方が立軸ポンプ２Ａよりも早くなる
。なお水位が排水運転可能最低水位ＷＬ１，ＷＬ２より
も上位から下降してくる場合では、立軸ポンプ２Ａの方
が立軸ポンプ２Ｂよりも早く排水運転を完了する。前述
のように排水運転開始タイミングに時間差をもたせるこ
とによって、同じタイミングで複数台ポンプの排水運転
を開始させていた従来の運転方法のような水位の急激な
低下が確実に防止され、気中運転と排水運転の繰り返し
周期を延長してポンプの延命化に寄与することができる
。またポンプ同士の互換性を確保して、交換部品の管理
を容易する。Next, the operation will be explained. Intake pipe 4A, 4B
Although the mounting positions of the intake pipes 4 and 4 are set at the same height,
A is set and installed at a position with a high degree of negative pressure, while
Since the intake pipe 4B is installed at a position where the degree of negative pressure is small, if the difference in degree of negative pressure is Δh1, the values of h1 and h2 that determine the lowest water levels WL1 and WL2 that allow drainage operation are h2. is lower than h1 by Δh1, and the lowest water level WL1 that allows drainage operation is made higher than WL2 by Δh1. Therefore, when the water level rises, the drainage operation starts earlier in the vertical shaft pump 2B than in the vertical shaft pump 2A. Note that when the water level falls from above the lowest water level WL1, WL2 at which drainage operation is possible, the vertical shaft pump 2A completes the drainage operation earlier than the vertical shaft pump 2B. As mentioned above, by providing a time lag in the start timing of drainage operations, the sudden drop in water level that would occur in the conventional operation method, where multiple pumps start draining operations at the same timing, is reliably prevented, making it possible to avoid submerged operation. This can contribute to extending the life of the pump by extending the repetition cycle of the drain operation. It also ensures compatibility between pumps and facilitates management of replacement parts.
【００１８】図６は、請求項３の発明の一実施例を適用
した立軸ポンプの概略構成図を示す。なお、前記請求項
１および請求項２の発明の実施例と同一もしくは相当部
分には同一符号を付して、詳しい説明は省略する。図６
において、吸気管４Ａと吸気管４Ｂの出口の取付け位置
は同じの高さに設定され、かつ吸気管４Ａの通路面積を
吸気管４Ｂの通路面積よりも十分に大きく設定している
。FIG. 6 shows a schematic configuration diagram of a vertical shaft pump to which an embodiment of the invention of claim 3 is applied. Note that the same or equivalent parts as in the embodiments of the invention according to claims 1 and 2 are given the same reference numerals, and detailed description thereof will be omitted. Figure 6
In this, the mounting positions of the outlets of the intake pipe 4A and the intake pipe 4B are set at the same height, and the passage area of the intake pipe 4A is set to be sufficiently larger than the passage area of the intake pipe 4B.
【００１９】つぎに作動を説明する。吸気管４Ａの通路
面積は吸気管４Ｂよりも大きく、吸気抵抗は吸気管４Ｂ
よりも小さいので、空気の流入量は吸気管４Ａの方が多
くなる。今、水位が排水運転可能最低水位ＷＬ１，ＷＬ
２に向けて上昇しているとすれば、吸気管４Ａでは排水
運転可能最低水位ＷＬ１に到達するまで十分に空気を吸
い込むことができるので、立軸ポンプ２Ａは排水運転可
能最低水位ＷＬ１に到達した時点で排水運転に切り替え
られる。しかし吸気管４Ｂでは十分に空気を吸い込むこ
とができないので、立軸ポンプ２Ｂは排水運転可能最低
水位ＷＬ１よりもΔｈ２だけ低い水位ＷＬ２で排水運転
に切り替えられることになる。つまり水位上昇時の排水
運転開始タイミングは、立軸ポンプ２Ｂの方が立軸ポン
プ２Ａよりも早くなる。なお、水位が排水運転可能最低
水位ＷＬ１，ＷＬ２よりも上位から下降してくる場合で
は、立軸ポンプ２Ａの方が立軸ポンプ２Ｂよりも早く排
水運転を完了する。前述のように排水運転開始タイミン
グに時間差をもたせることによって、同じタイミングで
複数台ポンプの排水運転を開始させていた従来の運転方
法のような水位の急激な低下が確実に防止され、気中運
転と排水運転の繰り返し周期を延長してポンプの延命化
に寄与することができる。またポンプ同士の互換性を確
保して、交換部品の管理を容易する。なお、図示６は、
吸気管自体の太さを変えて通路面積を変化させているが
、同一サイズの吸気管を用い、その本数を変えて通路面
積を変化させてもよく、また吸気管の経路中に弁等の絞
り機構を設けて通路面積を変化させてもよいことはいう
までもない。Next, the operation will be explained. The passage area of the intake pipe 4A is larger than that of the intake pipe 4B, and the intake resistance is greater than that of the intake pipe 4B.
, the amount of air flowing into the intake pipe 4A is larger. Currently, the water level is the lowest water level WL1, WL that allows drainage operation.
2, the intake pipe 4A can suck in enough air until it reaches the lowest water level WL1 that allows draining operation, so the vertical pump 2A reaches the lowest water level WL1 that allows draining operation. can be switched to drainage operation. However, since the intake pipe 4B cannot sufficiently suck in air, the vertical shaft pump 2B is switched to drain operation at a water level WL2 lower by Δh2 than the lowest water level WL1 that allows drain operation. In other words, when the water level rises, the drainage operation starts earlier in the vertical shaft pump 2B than in the vertical shaft pump 2A. In addition, when the water level falls from above the lowest water level WL1, WL2 that allows drainage operation, the vertical shaft pump 2A completes the drainage operation earlier than the vertical shaft pump 2B. As mentioned above, by providing a time lag in the start timing of drainage operations, the sudden drop in water level that would occur in the conventional operation method, where multiple pumps start draining operations at the same timing, is reliably prevented, making it possible to avoid submerged operation. This can contribute to extending the life of the pump by extending the repetition cycle of the drain operation. It also ensures compatibility between pumps and facilitates management of replacement parts. In addition, illustration 6 is,
Although the passage area is changed by changing the thickness of the intake pipe itself, it is also possible to use intake pipes of the same size and change the number of pipes to change the passage area. It goes without saying that a throttle mechanism may be provided to change the passage area.
【００２０】前記実施例では、２台の立軸ポンプ２Ａ，
２Ｂを使用して説明しているが、３台以上の立軸ポンプ
を使用しても本発明の実施が可能であり、前記実施例と
同様の作用効果を奏することができる。また本発明は、
前記実施例で説明した立軸ポンプのみに限らず、気中運
転を行なうことのできる他のポンプにも採用できること
はいうまでもない。In the above embodiment, two vertical shaft pumps 2A,
2B, the present invention can be practiced even if three or more vertical shaft pumps are used, and the same effects as in the above embodiment can be achieved. Moreover, the present invention
It goes without saying that the present invention is not limited to the vertical shaft pump described in the above embodiment, but can also be applied to other pumps that can be operated in air.
【００２１】[0021]
【発明の効果】以上説明したように、請求項１の発明に
よれば、吸気管の吸込みケーシング内に連通する取付け
位置を複数台のポンプ毎に高さ方向に互いに変位して設
定し、ポンプ毎の排水運転可能最低水位に高低差を付け
て排水運転開始タイミングに時間差をもたせるようにし
ているので、吸水井の水位が急激に低下するのを防止し
、気中運転と排水運転の繰り返し周期を延長させてポン
プの延命化を図り、かつポンプ同士の互換性を確保して
、交換部品の管理を容易にすることができる。また請求
項２の発明によれば、吸気管の吸込みケーシング内に連
通する取付け位置を、吸込みケーシング内に張出し形成
した抵抗体と水の旋回方向によって決定される円周方向
の圧力分布に基づいて複数台のポンプ毎に円周方向に互
いに変位して設定し、ポンプ毎の排水運転可能最低水位
に高低差を付けて排水運転開始タイミングに時間差をも
たせるようにしているので、吸水井の水位が急激に低下
するのを防止し、気中運転と排水運転の繰り返し周期を
延長させてポンプの延命化を図り、かつポンプ同士の互
換性を確保して、交換部品の管理を容易にすることがで
きる。さらに請求項３の発明によれば、吸気管の通路面
積を複数台のポンプ毎に互い変えて設定し、ポンプ毎の
排水運転可能最低水位に高低差を付けて排水運転開始タ
イミングに時間差をもたせるようにしているので、吸水
井の水位が急激に低下するのを防止し、気中運転と排水
運転の繰り返し周期を延長させてポンプの延命化を図り
、かつポンプ同士の互換性を確保して、交換部品の管理
を容易にすることができる利点がある。As explained above, according to the invention of claim 1, the mounting positions of the intake pipes communicating with the inside of the suction casing are set so as to be mutually displaced in the height direction for each of the plurality of pumps. By setting a difference in height between the minimum water level that can be used for each drainage operation and providing a time difference in the timing of starting drainage operation, it is possible to prevent the water level in the water intake well from dropping rapidly and to reduce the repetition period between submerged operation and drainage operation. It is possible to extend the life of the pump by extending the life of the pump, ensure compatibility between pumps, and facilitate the management of replacement parts. According to the second aspect of the invention, the mounting position of the intake pipe communicating with the inside of the suction casing is determined based on the pressure distribution in the circumferential direction determined by the resistor formed in an overhanging manner inside the suction casing and the swirling direction of the water. Multiple pumps are set so that they are displaced from each other in the circumferential direction, and the minimum water level at which drainage operation is possible for each pump is set at a different height, so that there is a time difference in the timing at which drainage operation starts, so that the water level in the water intake well It is possible to prevent a sudden drop in performance, extend the cycle of repeating submersible operation and drain operation to extend the life of the pump, and ensure compatibility between pumps to facilitate the management of replacement parts. can. Furthermore, according to the invention of claim 3, the passage area of the intake pipe is set to be different for each of the plurality of pumps, and the lowest water level at which drainage operation is possible for each pump is made different in height, thereby providing a time difference in the timing of starting drainage operation. This prevents the water level in the water intake well from dropping rapidly, extends the cycle of submerged operation and drainage operation to extend the life of the pump, and ensures compatibility between pumps. This has the advantage of making it easier to manage replacement parts.
【図１】第１の発明の一実施例を適用した立軸ポンプの
概略構成図である。FIG. 1 is a schematic configuration diagram of a vertical shaft pump to which an embodiment of the first invention is applied.
【図２】第１の発明の他の実施例を適用した立軸ポンプ
の概略構成図である。FIG. 2 is a schematic configuration diagram of a vertical shaft pump to which another embodiment of the first invention is applied.
【図３】第２の発明の一実施例を適用した立軸ポンプの
概略構成図である。FIG. 3 is a schematic configuration diagram of a vertical shaft pump to which an embodiment of the second invention is applied.
【図４】図３の一方のポンプの給気管の取付け位置を示
す底面図である。FIG. 4 is a bottom view showing the mounting position of the air supply pipe of one of the pumps in FIG. 3;
【図５】図３の他方のポンプの給気管の取付け位置を示
す底面図である。FIG. 5 is a bottom view showing the installation position of the air supply pipe of the other pump in FIG. 3;
【図６】第３の発明の一実施例を適用した立軸ポンプの
概略構成図である。FIG. 6 is a schematic configuration diagram of a vertical shaft pump to which an embodiment of the third invention is applied.
１ 吸水井 ２Ａ ポンプ（立軸ポンプ） ２Ｂ ポンプ（立軸ポンプ） ２ａ 羽根車 ２ｂ 羽根車 ３Ａ 吸込みケーシング ３Ｂ 吸込みケーシング ４Ａ 大気開放吸気管 ４Ｂ 大気開放吸気管 ５ 抵抗体 Ｒ 水の旋回方向 ＷＬ１ 排水運転可能最低水位 ＷＬ２ 排水運転可能最低水位 1 Water absorption well 2A Pump (vertical shaft pump) 2B Pump (vertical shaft pump) 2a Impeller 2b Impeller 3A Suction casing 3B Suction casing 4A Air intake pipe 4B Intake pipe open to atmosphere 5 Resistor R Water rotation direction WL1 Minimum water level for drainage operation WL2 Minimum water level for drainage operation
Claims (3)
連通して取付けられている大気開放吸気管から吸気でき
るように構成した複数台のポンプの羽根車の位置をそれ
ぞれ同じ高さに設定して吸水井に設置し、これらポンプ
それぞれの前記吸気管の吸込みケーシング内に連通する
取付け位置をポンプ毎に上下方向に互いに変位して設定
し、ポンプ毎の排水運転可能最低水位に高低差を付けて
、排水運転開始タイミングに時間差をもたせて運転する
ようにしたことを特徴とする複数台ポンプの運転方法。[Claim 1] The impellers of a plurality of pumps configured to be able to take in air from an air-opening intake pipe installed in communication with the suction casing on the upstream side of the impellers are set at the same height. The pumps are installed in a water suction well, and the installation positions of the intake pipes of each of these pumps, which communicate with the suction casing, are set so as to be displaced from each other in the vertical direction for each pump, and the minimum water level at which drainage operation is possible for each pump is set at a height difference. , a method of operating multiple pumps, characterized in that the pumps are operated with a time difference in the timing of starting drainage operation.
連通して取付けられている大気開放吸気管から吸気でき
るように構成した複数台のポンプの羽根車の位置をそれ
ぞれ同じ高さに設定して吸水井に設置し、これらポンプ
それぞれの前記吸気管の吸込みケーシング内に連通する
取付け位置を前記吸込みケーシング内に張出し形成した
抵抗体と水の旋回方向によって決定される円周方向の圧
力分布に基づいてポンプ毎に円周方向に互いに変位して
設定し、この取付け位置の変位に伴って変化する負圧度
に応じてポンプ毎の排水運転可能最低水位に高低差を付
けて、排水運転開始タイミングに時間差をもたせて運転
するようにしたことを特徴とする複数台ポンプの運転方
法。[Claim 2] The impellers of a plurality of pumps configured to be able to take in air from an air-opening intake pipe installed in communication with the suction casing on the upstream side of the impellers are set at the same height. Based on the pressure distribution in the circumferential direction determined by the resistor formed in the suction casing and the resistance body that is installed in the water suction well and communicates with the suction casing of the intake pipe of each of these pumps and the swirling direction of the water. The pumps are set to be displaced from each other in the circumferential direction, and the minimum water level at which drainage operation is possible for each pump is set with a height difference depending on the degree of negative pressure that changes with the displacement of this mounting position, and the timing for starting drainage operation is set. A method of operating a plurality of pumps, characterized in that the pumps are operated with a time difference.
連通して取付けられている大気開放吸気管から吸気でき
るように構成した複数台のポンプの羽根車の位置をそれ
ぞれ同じ高さに設定して吸水井に設置し、これらポンプ
それぞれの前記吸気管に通路面積差をもたせ、この通路
面積差にともなって変化する吸気抵抗に応じてポンプ毎
の排水運転可能最低水位に高低差を付けて、排水運転開
始タイミングに時間差をもたせて運転するようにしたこ
とを特徴とする複数台ポンプの運転方法。[Claim 3] The impellers of a plurality of pumps configured to be able to take in air from an air-opening intake pipe installed in communication with the suction casing on the upstream side of the impellers are set at the same height. The intake pipes of these pumps are installed in a water intake well, and the intake pipes of each of these pumps have a difference in passage area, and the lowest water level at which drainage operation is possible for each pump is varied according to the intake resistance that changes with this difference in passage area. A method for operating a plurality of pumps, characterized in that the operation starts with a time difference.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3277691A JP2662665B2 (en) | 1991-02-27 | 1991-02-27 | How to operate multiple pumps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3277691A JP2662665B2 (en) | 1991-02-27 | 1991-02-27 | How to operate multiple pumps |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04272496A true JPH04272496A (en) | 1992-09-29 |
| JP2662665B2 JP2662665B2 (en) | 1997-10-15 |
Family
ID=12368246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3277691A Expired - Fee Related JP2662665B2 (en) | 1991-02-27 | 1991-02-27 | How to operate multiple pumps |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2662665B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009197648A (en) * | 2008-02-20 | 2009-09-03 | Ebara Corp | Liquid pump and liquid pump system |
| JP2012122418A (en) * | 2010-12-09 | 2012-06-28 | Kubota Corp | Preceding standby operation pump |
-
1991
- 1991-02-27 JP JP3277691A patent/JP2662665B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009197648A (en) * | 2008-02-20 | 2009-09-03 | Ebara Corp | Liquid pump and liquid pump system |
| JP2012122418A (en) * | 2010-12-09 | 2012-06-28 | Kubota Corp | Preceding standby operation pump |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2662665B2 (en) | 1997-10-15 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |