float switches 1

[deletethisaccount]

I'm installing a pump, maybe a centrifugal, might go for a self priming, anyway. quite small, about 20m head, 3-4 cubic metres hour, and I need a float switch. Usual suppliers clearly know nothing of float switches and I needed some recommendations. The application is in a hot climate outdoors in asia. The usual search engine routine has just thrown up a load of spirit crushing adverts. Does anyone have any sound direction on this, uk supplier preferable??

 

[ScottyUK]

What are you trying to switch - a PLC input or a contactor? What media is the switch in contact with? Any other considerations - hazardous area, suspended solids, sewage etc? Without more information I'm not surprised the vendors aren't able to help.

Have you looked at the types carried by RS Components?


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If we learn from our mistakes I'm getting a great education!

 

[Artisi]

Seems the suppliers aren't the only ones who know nothing about float switches - more info. required, alternately the following link should help.

http://www.ask.com/web?q=float+level+switches&search=&qsrc=0&o=0&l=dir

 

[deletethisaccount]

Thanks for the sarcasim....er...I mean help people. But I never claimed to know about float switches which is why I posted!?! I do however know about pumps but have never needed a float switch so I needed a good educated supplier to enlighten me.

The site is a bed with one horizon of aggrigate and another of soil, there are limited suspended solids, some sand in low amounts, the water has a high ammonia concentration as it is proessed water. roughly 10m depth, the site is hazardous due to it being in an area where effluent may or may not find its way into the system through leachate.

 

[ScottyUK]

Sounds like a damned good application in which to avoid a mechanical switch. What's your budget? Before you answer 'as cheap as possible', bear in mind cost of downtime, cost of switch maintenance, cost of a wrecked pump, cost of liquid pouring all over the site, cost to you of a pissed off gaffer, etc.

I would be looking at something like a capacitive type from, say, Vega Controls, e.g. RS 539-5735. These are pretty much fit & forget once they are set up and will tolerate the environment. Check the compatibility of the stainless steel with ammonia - other materials are available. If you can stretch to the cost a true non-contact type such as a radar or ultrasonic would be even better. Guided wave radar is another good candidate given waveguide material compatibility with ammonia. Have a look at Milltronics (now Siemens, I think) and Rosemount as a couple of other leads.

But all that depends on your budget - I work in an industry where reliability is highly prized and a high initial cost is often acceptable if it buys reliability and low maintenance. Your situation is possibly different - only you know at the moment.


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If we learn from our mistakes I'm getting a great education!

 

[deletethisaccount]

Thanks scottyuk, Budget is not a problem, I would always favour dependability over cost as kit is not always as cheap as it looks if your forever maintaining and trouble shooting the thing. I saw some switches at triton controls ltd that stood out (heard of them?) instead of the mercury switch which i had in mind they have a rolling ball setup which is a bit more eco friendly due to not using heavy metals which will keep the client happy. I have a mechanical/envir background and generally stay away from elec-trickery, not my dept, but I think their model is generally universal & would marry to most uk pumps. They use hypalon (brand name me-thinks) which is chemically resistant. I will have a look at the ones you sugested also. radar or ultrasonic may be an over kill, I just wanted a set-up that initiated the pump when the water reached a certain height. Let me know what you think of the triton float switch model LR02 if you have a little time, much appriciate the advice.

 

[ScottyUK]

Looks reasonable, but I'd probably go for an environment-hostile mercury type using the same basic principle for outright reliability. It's an old fashioned way of doing it but proven by the passage of many years. I don't have any knowledge of that specific manufacturer's products, but there are plenty of companies making that basic design. Not as good as non-contact in my experience but there are a lot of pump controllers working reliably using them. Roughly how much does that switch cost?

Meant to ask: is this a surface tank with accessible walls, or a buried type?


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If we learn from our mistakes I'm getting a great education!

 

[KernOily]

Another option would be the tuning-fork type made by Endress-Hauser. They are reliable as a rock in all kinds of nasty services. Punch up Endress-Hauser and look for liquid level controls. Pete

 

[Yorkman]

Warrick also makes an electronic probe/level control that we use in cooling tower basins. We use them to cycle make up water soleniods and trigger high and low level alarms, it could be used to cylce a pump as well.

I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int./JCI

 

[ScottyUK]

Good recommendation on E&H's products. Not cheap, but quality rarely is. Pepperl & Fuchs are another manufacturer of first class instrumentation with a similar range to E&H or Vega.

http://www.pepperl-fuchs.com/select..._currentTreeName_select=tree_classification_1

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If we learn from our mistakes I'm getting a great education!

 

[deletethisaccount]

Thanks for the info good folk, I have found a decent enough set up, manufacturer is the same as pump so took a lot of hassle away, but i see what your saying abut the mercury switch being a bit more applicable, however it looks like i'm going to be using them a lot now so i still cherish the info put down & have looked at all of them. In answer to your question scottyuk the site is a reed bed dug at a lower gradient to the effluent output which is fed into series of trenches with various residence times. The wall are clay bricks but this is just a pilot scheme, the real deal (if things go well) will be acres and acres of land providing cleaned water from produced water & creating a new eco-system for all the local wildlife. All together now, ARRRRRRW

http://WWW ISNT

THAT NICE FOR THE ENVIRONMENT. Thanks all.

 

[electricsub]

Based in the Uk i have used Triton floats for, nearly 20 years, not had one problem with them, used on applications within the water industry ( water & sewage ) also used them on non water industry process's.I have changed them after years of use or abuse, by clients and liquids.
They used to make a Mercury float, but change to a "ball" a few years ago due to EU requirement of non mercury components in the water industry.
There range is still top class and definatly value for money.
We still buy about 30/50 a year from them ( no i do not work for them ) when compared with say Flygt Pumps ENH 10 series, it'd say it's better, only a personal view.
They also make a IS verion but you would still need a barrier relay for a use in a hazardous area.
They are based in West Auckland, Co Durham - UK
If using as a on/off you should use two floats and not just a single for both actions.
I also use the Ultrasonic / Radar / Probes (capacitance or conductivity versions ) all have there markets, and depending on the manufacturer and application they are very good and we use and service them on a dailly basis. manufacturers of these mentioned by others above all have a
good reputation.

Regards

 

[pumpking]

If it is very critical, it would be worth going for three floats, one low level, ont high level and another high level in case the first malfunctions.
We pump chemial, and we like to recomend this in all cases just in case. On the low level side, also look at pump protection monitor to switch it off in case of dry running.

Ash Fenn

http://www.cdrpumps.co.uk

 

[deletethisaccount]

I went for two switches anyway, off/on. At this scale this is sufficent, for the current beds recieving 30,000 - 40,000 cubic metres of produced water a day each (H2O with dissolved oil of varying grades) however I will be using a more sophisticated set up. Do add if anyone uses more than say 4 or 5 switches for level changes within a moving system.

Being in East Africa the evapotranspiration and vast herded local cattle "helping themselves" to water (wether cleaned or not!) has a fluctuating impact on water levels.

And as for the wet season?? Forget it!