【正文】 ed water 排出液體 G r u n d f o s F L O W T H I N K I N G28 Formula for calculating the weight of displaced water 計(jì)算排出液體重量的公式 The uplift must be prevented by making an slightly bigger down force 通過比浮力大向下的力抗浮 Fdown FUplift Putting material around the slab area, will create the Fdown 在底部區(qū)域放置重物能產(chǎn)生向下的力 Density of concrete/gravel : ρwater = 2 2,5 混凝土的比重 Density of water : ρwater = 1 水的比重 Slab area (sa) The trick is to make the pit heavier than the weight of the displaced water 解決方法為讓泵站比排出液體的重量重 What is uplift? 什么是浮力 2u p l if tF = wa te rrH??? ? ?H r FUplift FDown 2do w nF = ( sl a b a r e a ) m ate r ialrH??? ? ?G r u n d f o s F L O W T H I N K I N G29 My pit must be installed in the street?? 泵站需要安裝在街道上 ? The consultants want to install the pit in a area with heavy traffic. ? 客戶需要將泵站安裝在交通繁忙的區(qū)域 ? Which solution can we offer him? ? 我們能提供什么解決方案？ Situation情形 G r u n d f o s F L O W T H I N K I N G30 The norm EN 124 precises the design/load of the manholes top for traffic and sidewalk area EN124標(biāo)準(zhǔn)規(guī)定交通和人行道區(qū)域頂蓋設(shè)計(jì)和荷載 Class A15 ( 15 kN) for sidewalk and bicycle area A15級(jí) ( 15 kN)可以承受人行道和自行車區(qū)域 Class B125 ( 125 kN) for pavements, sidewalk zones B125 ( 125 kN)可以承受公路和人行道區(qū)域 Class C 250 for gully C 250可用于集水溝 Class D 400 for roads, streets and parkings D 400可用于道路、街道和停車場(chǎng) Class E 600 and F 900 A pit like PUST can withstand 1000 kg (1 kg = 10 N) PUST可以承受1000kg荷載 (1 kg = 10 N) Max load on top of the pit 泵站頂蓋最大承載 G r u n d f o s F L O W T H I N K I N G31 Concrete basement 混凝土底板 Cast iron manhole cover 鑄鐵蓋板 Concrete cone 混凝土錐 Orings O形圈 Asphalt 瀝青 Asphalt瀝青 How to install the pit in the street 如何將泵站安裝在街道上 。 – To long a distance may cause sedimentations and risk for clogging due to long stay time in the pit – 距離太遠(yuǎn)，水泵運(yùn)行周期過長，增加了沉淀和堵塞的風(fēng)險(xiǎn) ? The right distance will give the optimal tank size ? 正確的啟停液位距離是池型優(yōu)化設(shè)計(jì)的關(guān)鍵 G r u n d f o s F L O W T H I N K I N G11 ? T = Pumping cycle period ? 水泵運(yùn)行周期 ? Ts = Stopping period ? 停泵周期 ? Tp = Pumping period ? 泵送周期 ? T=Tp+Ts ?2 – Calculating the effective volume – theory 有效容積計(jì)算－原理 6T T Tp Ts Start Stop ? Zmax = maximum number of startstop /hour ? 每小時(shí) 最大啟停次數(shù) ? = minimum cycle period [h] = T ? 最小運(yùn)行周期 max1ZG r u n d f o s F L O W T H I N K I N G12 Qww/Qp Pumping period Tp 泵送周期 Stopping period Ts 停泵周期 Cycle period Tp + Ts 運(yùn)行周期 If Qww= pump capacity = 1 then: 如