Topic: 去水 formula discussion

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Posted by: clownfish
Posted on: 2004-03-10 12:24

hope to discusse to all member and set up a formula for 去水 calculation

by theory :
Volume = Velocity x Area
Velocity = (2gH ) 1/2
Area = pie x r 2 = pie/4 x D 2

g = 9.8 m/s 2 ,
H = height from 滴流位去水 to s沙缸的落水喉的出水口 ( m )
1 L = 0.001 m 3
pie = 3.1416
D = 落水喉 [color=red]inner diameter [/color] ( m )

Example :
H = 18 " = 0.4572 m , D = 1" = 2.54 cm = 0.0254 m
Velocity = ( 2gH ) 1/2 = ( 2 x 9.8 x 0.4572 ) 1/2 = 2.9935 m/s
Area = pie /4 x D 2 = 3.1416/4 x 0.0254 2 = 5.067 x 10 -4 m 2

Volume = Velocity x Area = 2.9935 m/s x 5.067 x 10 -4 m 2 = 1.5168 x 10 -3 m 3 / s

1 hour Volume = 1.5168 x 10 - 3 m 3 /s x 3600 s = 5.460 m 3 /s

1 L = 0.001 m 3
so
Volume per hour = ( 5.460 m 3 /s ) / 0.001 m 3 = 5460 L/hr.

from above calculation [color=blue]1" diameter and 18" height can support 5460 L/hr [/color] :D
but this result r 100% perfect data. [color=blue]but after some factor ( friction , corner , turbulence ............. ) it should be lower .[/color]
we should add in [color=red]" safety factor " [/color]
Example : 5460 L/hr x 0.8( safety factor ) = 4368 L/hr.
so u only can use return pump about 4300 L/r.

but safety factor = 0.8 / 0.9 /0.7 :?)
i hope as much as member provide your tank data
1)return pump xxx L/hr
2) 落水喉 [color=red]inner diameter [/color]
3)H = height from 滴流位去水 to s沙缸的落水喉的出水口 ( m )
from yours data maybe we can come out that
safety factor = 0.X .
it may help use to consider during tank set up :P
kindly provide your data and commend.

thank you :D:D
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Posted by: 幻之無極兇眼男
Posted on: 2004-03-10 14:12

好似放錯版喎:I
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Posted by: 岩礁園丁
Posted on: 2004-03-10 14:42

應該放係 [過濾器材] 定係 [其他器材] 好呢 ?
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Posted by: clownfish
Posted on: 2004-03-10 15:14

He He He. sorry :I:I
forgot to said. i realy hope get many response from member. after data collection completed. i will move it to 其他器材 ok kah ?? :I:I:P
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Posted by: clownfish
Posted on: 2004-03-10 15:16

丁 san
u r using sump tank. pls provide your data lar :P
thank you :D
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Posted by: 老坑
Posted on: 2004-03-10 15:18

may be.......try to search for the post that mirrorguy replied before.....:D
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Posted by: 岩礁園丁
Posted on: 2004-03-10 15:53

哈哈, 我唔曉計數, 只係憑經驗判斷, [color=red]落水喉越大越冇壞[/color], 我180升水, 上水泵只係30-R, 4分上水, 就用到吋半落水, 再加上可調高度的落水口, 完全排除左落水問題.:D
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Posted by: clownfish
Posted on: 2004-03-10 15:58

no problems :D
just provide me
1)return pump xxx L/hr
2) 落水喉 inner diameter
3)H = height from 滴流位去水 to s沙缸的落水喉的出水口 ( m )
i will calculate it :D

all using sump tank member
kindly give me your data. thank you :D:D

老坑 san
thank you :D
i will try to seacrh it :D
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Posted by: haiven
Posted on: 2004-03-10 16:43

Example :
                                               H = 18 " = 0.4572 m , D = 1" = 2.54 cm = 0.0254 m
                                               Velocity = ( 2gH ) 1/2 = ( 2 x 9.8 x 0.4572 ) 1/2 = 2.9935 m/s
                                               Area = pie /4 x D 2 = 3.1416/4 x 0.0254 2 = 5.067 x 10 -4 m 2

                                               Volume = Velocity x Area = 2.9935 m/s x 5.067 x 10 -4 m 2 = 1.5168 x 10 -3 m 3 / s

                                               1 hour Volume = 1.5168 x 10 - 3 m 3 /s x 3600 s = 5.460 m 3 /s

                                               1 L = 0.001 m 3
                                               so
                                               Volume per hour = ( 5.460 m 3 /s ) / 0.001 m 3 = 5460 L/hr.



完完全全totally fully 唔知係乜∼∼∼！
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Posted by: 白熊
Posted on: 2004-03-10 17:55

clownfish san, 個safety factor 我返而會用1.1添.
你計出黎5460L/H is for 1" pipe with 18"揚程 in 1 hour, 只係剛剛平衡, 流水量細過5460L/H 會慳電D, 大過5460會用盡條喉, 但最好接近哩個數值, 唔好相差太遠.
formula.....都好耐無計囉, 見返都有D頭痛:D
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Posted by: choinm
Posted on: 2004-03-10 19:50

1)return pump xxx L/hr
    1200L/hr

2) 落水喉 inner diameter
    3/4"

3)H = height from 滴流位去水 to s沙缸的落水喉的出水口 ( m )
    33"
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Posted by: 岩礁園丁
Posted on: 2004-03-10 19:57

上水喉內俓 : 18mm
落水喉內俓 : 40mm
揚升高度 : 1.3m
上水泵規格 : 見圖
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Posted by: damieN
Posted on: 2004-03-10 22:43

he know me,
i don know him.:P
xx(
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Posted by: clownfish
Posted on: 2004-03-10 23:08

吾好意思,表達能力太差,令尼地誤會左 :I:I
我要個 H = D ( 如下圖 ) , 請比多次 :P
多謝 :D
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Posted by: clownfish
Posted on: 2004-03-10 23:35

個公式係計流水量,
流水量=流速 x 面積 .
主要影響流速的因素係 H ( 即係上圖個D ),H (D ) 越大,速度越快 ,
好似丁生叫人將落水喉插入水中,落水最快,尼個做法個H會係最大,流速亦會係最快 :D
再來係面積 , 好似丁生所講 " 落水喉越大越冇壞 " :P
當計到流水量 , 我地就可知可用几大的上水泵 .

但係條數計出來是否正確 , 應唔應該打折扣尼 ? 如要又扣几多啦 ??
條落水喉有摩擦係數,有轉角, 應該下水量會減少 .
但係如熊 生所講,上水亦都要打折,所以他孝慮safety factor is 1.1 :D

希望多d 魚友提佺資料比小弟計下,看條公式掂唔掂
thank you :D:D
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Posted by: wongkf
Posted on: 2004-03-11 00:01

clownfish,

你條數計錯左, 唔係用呢個方法計的. 係用 Q=k x square root of P.
Q = flow
k = k factor
P = Pressure
要選泵仲要有pump curve如果你有興趣可以找書看看, 唔太難計
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Posted by: clownfish
Posted on: 2004-03-11 08:53

O :O):I:P
wongkf san
thank you very much of your information.:D
can u teach me more about your formula .
Q1 : P = delta P ?? pressure diferent from 2 location ? ( i guest )
Q2 : k = k factor , any formula of K ?? or what is the consider / content of K ??
Q3 : can u pls make an example , like the example i do calculation :P so to make me more understanding your formual and i can know how big diferent from my calcultion and you :P
Q4 : i think ( think only ) i am using the simplest formual to calculate it. many factor ( friction , specific gravity ........... was ignore ) and your formula should be more acculate including those factor . or i am totaly wrong formula using ??
kindly teach me. thank you very much :D

PS : my purpose to come out this calcultion is hope to make a simple ( reference ) guide line for everybody . so that when we set up tank we can know the 流水量 so we won't use too big pump and 去水 become problem :P

since u r familiar with such calculation. can u help to make this guide line :P
thank you :D

below r the data i refer for this calculation :P
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Posted by: haiven
Posted on: 2004-03-11 09:08

老兄，你終於可以打中文拿∼∼∼係咪手寫板呀？
我個泵55R-5 每分鐘70公升，即4200L/H，揚程8.2米高，來自
http://www.aquarium.org.hk/cgi-bin/ch/topic_show.cgi?id=7290&h=1&bpg=1&age=0
六分喉上水，一寸落水，落水位到沙缸距離約0.5米，請幫我計計∼∼
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Posted by: clownfish
Posted on: 2004-03-11 09:42

:D:D night time at home have 手寫板 but very tire leh :P
day time only can key in english :(

if follow my formula
一寸落水，落水位到沙缸距離約0.5米
result = 5755 L/hr. ( should be ok )
if 3/4 " 落水 , than result = 3237 L/hr. ( NG )

sorry would like to double confirm to u
1)一寸落水 >> 1 " is outside diameter or inner diameter ??
hope can get your reply soon.
like to know my formula is OK or NG :D:P
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Posted by: choinm
Posted on: 2004-03-11 09:43

choinm wrote:
1)return pump xxx L/hr
[$nbsp][$nbsp][$nbsp][$nbsp]1200L/hr

2) 落水喉 inner diameter
[$nbsp][$nbsp][$nbsp][$nbsp]3/4"

3)H = height from 滴流位去水 to s沙缸的落水喉的出水口 ( m )
[$nbsp][$nbsp][$nbsp][$nbsp]33"



上述資料冇錯，細佬個缸係側上去水，唔該幫手計計。
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Posted by: clownfish
Posted on: 2004-03-11 10:56

choinm san
result = 4158 L/hr

kindly take note
1)i am not sure calculation correct or not.
( waiting wongkf san advise )
2) result r perfect status. should discount some % .due to corner , friction .......

hope can get your commend regarding this data reasonable or not

thank you :D
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Posted by: choinm
Posted on: 2004-03-11 10:57

上面托氏定理有兩例，但第二例解答下文冇咗，可否出埋下文，因細佬個缸同個例一樣。
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Posted by: clownfish
Posted on: 2004-03-11 11:08

some simple refence table .
but no idea OK or NG.
kindly commend and provide your tank data.
so that i can adjust it / correct it
thank you :D:D
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Posted by: clownfish
Posted on: 2004-03-11 11:24

choinm san
as your request but maybe not much help for the next example
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Posted by: clownfish
Posted on: 2004-03-11 11:26

some other theory :D
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Posted by: clownfish
Posted on: 2004-03-11 11:31

those theory r basic developemnt for practical use
i think wongkf san formula should be more pratical use.
can't wait , hope he can explane his formula more detail.
now i want to try his formula but no idea of K factor how to calculate . my book don't have this :(

wongkf san
i am wait your advise .
pls teach me
thank you :D
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Posted by: choinm
Posted on: 2004-03-11 12:22

唔該哂clownfish兄幫細佬上咗堂物理。

細佬以前覺得去水多少只同去水孔大小有關，而家先知管高亦有影響。

唔知有冇理解錯，你個表意思係
用一尺長半吋喉去水，上水泵唔好大過892L/hr，唔係就去唔切。
用一尺長一吋喉去水，上水泵唔好大過3567L/hr，唔係就去唔切。
......
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Posted by: clownfish
Posted on: 2004-03-11 12:38

Yes, but i am not sure my calculation ok or not :D
and i was confuse 一吋喉 mean outside diameter or inner diameter ??
can u teach me :D
and i want to more clearly identify the height meaning , it have 2 case
pls refer below drawing
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Posted by: clownfish
Posted on: 2004-03-11 12:40

case 2 .
depend your setting
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Posted by: choinm
Posted on: 2004-03-11 13:05

香港習慣1吋喉即內徑有1吋。

應咁樣改可能好的：
用半吋喉垂直距離1呎去水，上水泵唔好大過892L/hr，唔係就去唔切。
用1吋喉垂直距離1呎去水，上水泵唔好大過3567L/hr，唔係就去唔切。

再睇真個表，發現：
用1吋喉垂直距離1呎去水，上水泵唔好大過3567/hr，唔係就去唔切。
用1吋喉垂直距離1.5呎去水，上水泵唔好大過4368L/hr，唔係就去唔切。

即係話用1吋喉去水，垂直距離1呎去水3567L/hr，改為垂直距離1.5呎去水就增加到4368L/hr，高半呎去水量可以多801L/hr !

魚友如發現去水去唔切，除換細泵或換條粗的去水喉外，另一辨法係升高個缸?
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Posted by: clownfish
Posted on: 2004-03-11 13:31

thank you :D

魚友如發現去水去唔切，除換細泵或換條粗的去水喉外，另一辨法係升高個缸?
Yes :D , so i think last time do happen some fish friend that setting as case 2 .水去唔切 , but change to case 1 水去 become OK :D

from 138 theory V=(2gH)squra . when H increase >> velocity increase . so flow rate increase :D

or another way. when 水去唔切 the water level will become higher .so some bio ball will dip inside water. but when the water level increase to some level will not increase any more. becoz the H increase make the water flow faster ,flow rate become balance at that level so water level maintain at that level :D

.
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Posted by: 岩礁園丁
Posted on: 2004-03-11 13:55

上水泵只要唔係大到離普或細到離普, 結果都會取得上落水平衡, 分別只係水位高低.
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Posted by: 白熊
Posted on: 2004-03-11 14:27

睇黎都好難計到個結果:(
丁丁所講既 factor 一定要加埋入去, 滴漏槽既水位高度會成為水壓, 直接加強落水速度; 落水喉如果插入水中, 落水一定快好多(唔知係"大氣壓力"還是係"虹吸作用"?)
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Posted by: Dickson
Posted on: 2004-03-11 14:40

仲有,多口問句;如果落水喉伸入沙缸水面下與在沙缸水面上有冇前別?若有,對以上定律有冇影响?
                          
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Posted by: wongkf
Posted on: 2004-03-11 14:54

It's true that your theory can be used to estimate the maximum flow rate of 去水 pipe, but substitue "D" = H is wrong.
You should substitue the height of "level A" in the formula, that is, the water level of the falling chamber of main tank.
The maximum water level allowed is equal to the height of the falling chamber of main tank. So assume your last chamber height is 1m and your pipe size is 0.025m. Then the maximum circulation flow rate allowed would be 7200 L/H. (Assume no friction loss, the falling pipe connect to sump tank without elbow)
So,
if circulation rate > >7200 L/H, the water level of the whole tank rise
If circulation rate = 7200 L/H, the falling chamber would full of water
if circulation rate < 7200, the falling chamber would not full.
Assume "level A" of falling chamber is 0.2m , then, the actual circulation rate is about 3500 L/H.
So, by measuring the height of "level A" and your pipe size, you can estimate your existing circulation flow rate.
But, for the above example, is it mean that we cannot buy a pump of larger than 7200L/H? The answer is no, we still can have pump larger than 7200L/H.
Why? It is because 7200L/H is only the specified flow rate of the pump. It mean that under no resistance, it can output 7200L/H.
But it's true that the total flow rate of the two outlets cannot be larger than 7200L/H.

Example xx)
To size the pump , you need full hydraulic calculation.
Q in L/min
P in bar (assume 1 bar = 10m)
Refer to the drawings
Assume you want to have about 2000 L/H, that is, about 1000L/H from nozzle 1, Q1 = 17 L/min
assume k factor of nozzle 1 = 100, (just assumption, usually check from table)
then, pressure at 1 (P1):
Q1 = 100 x sqrt (P1)
17 = 100 x sqrt(P1)
thus, P1 = 0.0289 bar
neglect length of 1-2, assume supply pipe = 20mm
equivalent lenght (EL) of 20 mm elbow = 0.3m (usually from table),
assume length of 1-3 = 1m
total EL from 1 to 3 = 1 + 0.3 = 1.3
k factor for 20mm pipe, k20 = 3.8 x 10^-5
then pressure loss across 1-4, P14 = k20 x EL x Q13 ^2,
(actual P = k x EL x Q^1.85, but I assume Q^2 for simplification)
P14 = 3.8 x 10 ^ -5 x 1.3 x 17^2
P14 = 0.014 bar
thus, P at 4, P4 = P1 + P14 = 0.0289 + 0.014 = 0.043 bar,
neglect the T joint at 4 for simplification (actually, you cannot neglect that)
Assume k factor for nozzle 1 = nozzle 3 = 100
Then Q3 = 100 x sqrt (0.043)
Q3 = 20.7 L/min

So, total flow rate from 5 to 4, Q5 = 17 + 20.7 = 37.7 L/min,
Assume length of 5 to 4 = 0.5,
then P loss from 5 to 4, P45 = k20 x Q5 ^ 2 x EL, (EL = 0.5 + 0.3 = 0.8)
thus, P45 = 3.8 x 10^ -5 x 37.7^2 x 0.8 = 0.043 bar
thus P5 = P4 + P45 = 0.043 + 0.043 = 0.086 bar
Assume length of 5-6 = 1.5 m
P6 = P5 + static pressure + loss
P6 = 0.086 + 0.15 (static) + 3.8 x 10^-5 x 1.5 x 37.7^2 ( system characteristic)
P6 = 0.317 bar
P6 = 3.17 m
So, at 6 , P = 3.17m, 2262 L/H
When you plot this point on the pump curve, if the point is within the pump curve, then your pump can provide more than the flow you need, if it is outside the pump curve, the pump cannot provide sufficient flow.

Actually, if you want to check the exact flow rate, you can substitue, different flow at the above system characteristic, e.g. when Q = 0, P6 = 0.236 bar,
when Q = 10, P6 = 0.241, then the system characteristic curve can be plot on the pump curve. The intersection point is the operating point.

Please note all the above k factors are not true but just to illustrate the calculation. You have to refer to some book for the true value.
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Posted by: wongkf
Posted on: 2004-03-11 15:08

Please note that level A is counted from the bottom of the main tank
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Posted by: clownfish
Posted on: 2004-03-11 15:33

wongkf san
u r right. it should be using level A to calculate but hard to defind the A height . therefore i use the H to calculate.it is easy to measure and everybody can get it before tank setting , ofcoz this will come to less L/hr , but my target is to make simple guide to prevent pump too strong cause 落水 problems. so i prefer to estimate / calculate it smaller :P

thank you very much. u realy detail explanation .
and i need some time to study your example.:P
is good example . happy to get your support for this calculation.
i will try to make a simple guide line for 去水喉 diameter decision.
hope u can help to commend or do adjustment for that guide line :D
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Posted by: wongkf
Posted on: 2004-03-11 15:55

Level A is difficult to determine but the maximum height allowed for level A is constant. It is simply the height of your tank or the height of your chamber.
Rising the level of main tank actually cannot increase the flow rate. The maximum flow rate depend on the depth of the main tank only.
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Posted by: clownfish
Posted on: 2004-03-11 15:59

E....... :?)
A is count from " bottom of main tank to water level " ??

yeah notice 1 thing is haiven san have 去水 problems.
but i calculate the data he give Q = 5755 L/hr , but his pump is 4200L/hr .
should be OK . but.................. ???
can u help to calculate his tank flow rate.
is it we need to make some discount of the flow rate ??
or my make mistake calculation :I:I
thank you :D
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Posted by: clownfish
Posted on: 2004-03-11 16:21

wongkf san,
yes u r right. i can consider the max height as chamber height :D
but i prefer more safe data. so i use minimum ( height 去水喉 ) to calculate it :P becoz we also will place bio-ball inside the chamber. if i calculate the chamber height mean all the bio ball will be in the water :P

wongkf san,
regarding your A level i have some confuse .
my thinking : it should consider the height "H " from sump to main. as below drawing.
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Posted by: wongkf
Posted on: 2004-03-11 17:18

Firstly, the drain pipe of Haiven have two 90 degree elbows before coming down to the sump, right? I read from his drawing of the previous post.
Secondly, the sump tank is open to atmosphere. It's not a pressurized tank.
Thirdly, your question is becoming more complicated. I have to go to Fish Street Now :) , may get back to you later after I think more.
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Posted by: clownfish
Posted on: 2004-03-11 17:46

ok
thank you :D

wish u get a nice fish / coral :D:D
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Posted by: choinm
Posted on: 2004-03-11 19:54

等細佬今晚[$#20914][$#20937]用支針筒、短膠喉同長膠喉試[$#21523]今日學[$#22021][$#22050]。睇[$#21523]淨針筒去水、接短膠喉去水同接長膠喉去水，大家去水快慢一樣益或有快有慢。
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Posted by: wongkf
Posted on: 2004-03-11 20:05

我係fot, 魚街無咩想買的魚:(
用中文較易講,
你提出的托氐定理係假設一個大缸出一條細水喉, 缸的cross section area 大過條喉好多, 所以即使喉內水的velocity好大, 缸內水個velocity都 可當做0. total pressure = static pressure + velocity pressure. 所以缸底的total pressure = static pressure, 同water level 成正比
但當水進入喉之後, 喉頭同喉尾水velocity 根本一樣, . 托氐定理在這段喉不成立的, 所以這段喉的高度不能算在內.
我之前計算是假設下水喉直落, 無浸入水, 如果浸入水的影響就真係唔知點計, 不過我相信影響唔會太大.
haiven個泵揚程8.9m, 4200L/H 的話, 我相信個pump operating point 約在5m 及3000 L/H左右, 正確計算要用我之前所說的方法.
其實我覺得去水方面唔需要太多研究, 如果直落沙缸, 25MM應一定夠, 如果下沙缸之前走2個曲, 就用32MM, D喉大細價差不多, 用大D就搞掂.
個泵揚程如果有3M, 你就預佢流量會得番MAXIMUM CAPACITY x 20%至30%, 如果好似HAIVEN咁有成9M, 你預佢有60-80%. 唔洗計得好似我咁複雜
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Posted by: catlee
Posted on: 2004-03-11 20:34

choinm wrote:
等細佬今晚[$#20914][$#20937]用支針筒、短膠喉同長膠喉試[$#21523]今日學[$#22021][$#22050]。睇[$#21523]淨針筒去水、接短膠喉去水同接長膠喉去水，大家去水快慢一樣益或有快有慢。



你用幼喉實唔得咁計, 因為佢地所講 唔計的阻力, 會晌幼喉好明顯咁睇出來, 重有表面張力, 不奈爾 公式等等都要計埋, 大喉就唔使.
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Posted by: choinm
Posted on: 2004-03-11 22:05

catlee wrote:
你用幼喉實唔得咁計, 因為佢地所講 唔計的阻力, 會晌幼喉好明顯咁睇出來, 重有表面張力, 不奈爾 公式等等都要計埋, 大喉就唔使.



敢又係喎，不過玩[$#21523]冇所謂喇。

唔準既試驗1：
針筒入滿水，唔接喉，漏清時間約５秒。(眼睇出水係一條線，相就變左一滴滴)
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Posted by: choinm
Posted on: 2004-03-11 22:09

唔準既試驗2：
針筒入滿水，接約1呎膠喉，漏清時間約1秒多。(快好多,要映相已漏清。另膠喉已注滿水)
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Posted by: choinm
Posted on: 2004-03-11 22:27

唔準既試驗3：
針筒入滿水，接約3呎膠喉，漏清時間小於1秒。(最快。另膠喉已注滿水)

結論:條喉愈長(垂直計)，去水愈快。唔知[$#21873]唔[$#21873]?
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Posted by: clownfish
Posted on: 2004-03-11 22:28

魚街無咩想買的魚 >>下次lor.
幫我搞掂尼個蘇州屎先拉 :P

如果直落沙缸, 25MM應一定夠, 如果下沙缸之前走2個曲, 就用32MM, D喉大細價差不[$brvbar]h, 用大D就搞掂.
fully agree :D
未計之前唔覺, 計左之后真似1.5" 搞掂,唔使 "林".
( refer the table i post , 1 " min 3567L , 1.5" min 10000L 掂 :P )

寫左kam多 , 都係寫完它了 :D
根据伯努利定理
Z1+P1/r+V1 2/2g = Z2+P2/r+V2 2/2g
( can refer 之前d post )
以下圖作計萛 point A & B
Za = H3 - H4 , Zb = H2 ,
Pa = 大气壓 + H4r ,Pb = 大气壓 + H1r ,
Va = 0 ( as wongkf san explane ), Vb = ?
代入公式
Z1+P1/r+V1 2/2g = Z2+P2/r+V2 2/2g
> H3-H4 + 大气壓 /r+ H4r/r +0 = H2 + 大气壓/r + H1r/r + Vb 2 /2g
> H3 = H1 + H2 + Vb 2 /2g
> H3 - H1 - H2 = Vb 2 /2g
> H = Vb 2 /2g
>>> Vb = ( 2gH ) 0.5
g= 9.8 m/s 2 固定,所以唯一影響流速是 H . H 越大 V 越大 :P
不過請記得尼個計萛冇考濾到摩察阻力 :P
所以必需打個折扣 ( example safety factor = 0.8 ) :P
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Posted by: clownfish
Posted on: 2004-03-11 23:09

長途跋涉計左一輪,
不如 wongkf san 咁間單一句 " 如果直落沙缸, 25MM應一定夠, 如果下沙缸之前走2個曲, 就用32MM " 搞掂 :D
伯努利 不愧為 " 白努力 " :D:D

好高興choinm san 既試驗 proof that 影響流速是 H . H 越大 V 越大 :P

Dickson san
落水喉伸入沙缸水面下與在沙缸水面上 >> by theory only the H diferent , so this will effect the velocity. H 越大 V 越大 :P
if 沙缸水面下 1 " compare with 沙缸水面下 5 " ,by theory is same velocity . but actual due to friction 水面下5" should be litle slower :D

虹吸作用 basicaly can explane by 伯努利 too :D
maybe your can try it :P

i think until here we had go through a lot calculation , explanation , testing , and also with reference table. it should be enough lor :P
basicaly we can know that when we set up to 1.5 " will be very good enough for 去水 , even consider safety factor 0.8 still can support to 8000L.hr :P

now feel interest with haiven san problem.
haiven san,
your 去水 problems only just as 岩礁園丁 san drawing , water level higher only or full until main tank ??
can u share more information regarding your problems ?
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Posted by: wongkf
Posted on: 2004-03-11 23:38

我放棄la, 頭爆:)
佢個實驗都幾有趣, 加長喉後有"紅"吸作用令水流加快, 你的說法是對的, H大會加快去水. 不過加快幾多, "紅"吸作用我就唔識計了
其實因工作需要, 我只係識計pump果方面, 對去水唔多熟
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Posted by: clownfish
Posted on: 2004-03-12 08:31

wongkf san,
thank you very much of your support for this discussion.
i learn the pump calculation from u :D
sad that i am at Malaysia , if not can buy u a drink :D
than we discuse about the drink how fast go into our stomach :P

岩礁園丁 san
thank you help me fix the drawing :D
can u teach me what mistake i make so it cause the drawing can not show ??

Haiven san,
r u around . can i know more about your case :P
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Posted by: 岩礁園丁
Posted on: 2004-03-12 12:31

我只係同你 "take" 返呢欄o者..:)
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Posted by: clownfish
Posted on: 2004-03-12 12:38

OIC
thanks :D
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Posted by: choinm
Posted on: 2004-03-12 13:38

clownfish wrote:
wongkf san,
can buy u a drink :D
than we discuse about the drink how fast go into our stomach :P




唔好唔記得上帝俾我地男性下面個一條亦好值得研討。
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Posted by: clownfish
Posted on: 2004-03-12 15:17

choinm san
Ha Ha Ha :D:D:D
2 principle must remeber ,
1) H heigher , 去水 faster .................. so suggest do it under the bed :})
2) biger , 去水 faster ......................... small size is better :P
small size people . u should happy now :})
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Posted by: 岩礁園丁
Posted on: 2004-03-12 16:59

浪哥仔之前亦都無意中有過這樣的試驗 :

落水喉沉在水中時, 主缸滴漏槽水位在[color=blue]第二層[/color]生物球上,

而將落水喉升回出水面時, 水位急升至[color=blue]第八層[/color]生物球之上,

可見分別很明顯.
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