There are many temperature and level switches in gas turbine. Please if any one can explain the scientific and theoretical idea of operation of these two switches. I mean how these switches work and what is the physical phenomena behind it.

thanks a lot

 

As you say there are many different types, that's why no-one has responded. I suggest you do some reading.

Roy

 

I understand... but I mean, there is main idea for most temperature switches, like basic idea and all other types are just modifications of that idea. Anyway... thank you for your reply.

 

Have you tried Google?

Guess where this came from...

http://www.ccsdualsnap.com/pdf/TEMP2.pdf

 

Difference in thermal expansion is very common, this would cover bi-metal strips (temperature gauges), liquid in metal (the liquid expands to straighten a bourdon tube or expand a bellows), two dissimilar metals (one expand more than the other to activate a microswitch, vapour pressure (the vapour pressure changes with temperature and operates a pressure switch). Then you get electronic switches based on thermocouple, RTD, thermistor or some other temperature sensing device. I'm sure there are others but these are some of the main ones.

Roy

 

I run across this pretty frequently. There is simply massive amounts of information available on the World Wide Web, but many people type one search term into any search engine and when they don't get exactly what they're looking for, they quit looking.

Temp switch probably doesn't return much. Temperature switch probably returns a few more relevant hits. Temperature switch construction a few more. Temperature switch explanation a few more relevant hits. Temperature switch description a few more still.

In the "old days" when all there was to search was a card catalog in a library or the Table of Contents and/or Index in a book, it still took some effort to find some topics or terms or information. But today, when it's so easy to type a search term, or two, or three, or seven, to try to find information it just boggles the mind why people give up so easily. And, especially with the English language being what it is with respect to technical terms. We can use six different words or terms to describe the same piece of equipment or concept.

I think the reason there weren't any immediate responses was because a lot of people were waiting to see who would rip this guy a new one and how bad it would be. I think a lot of people have shown some remarkable restraint here on this one.

To the originator of this post, one of the best ways to learn about how things work is to go to http://www.wikipedia.org. There's even a site called "How Stuff Works". I've checked for 'temperature switch' on both, and there's not a lot of good information on the first hit. But there are related topics and terms that can be used to get some explanations of different types of temperature control devices (of which a temperature switch is one type of device).

Another really good way to understand equipment and devices is to visit various manufacturer's websites. The really good ones will go to some very good detail to explain how their products are better than others, and in the process, will provide some excellent detail about the device and its uses and applications. I have personally dealt with CCS Dual Snap personnel many times in the last three decades, and I can say their people provide excellent service and help. I can only believe one can learn a lot from the information on their website. GE used to use a lot of their switches (temperature and pressure) on their equipment.

A good place to get the names of various manufacturers would be from the devices in use on the machines at your site.

So, some more good search terms would be temperature sensors, temperature control devices, and so on. Just be prepared to spend some time doing research, trying different search terms (some you will learn as you search, some you will "click through" on (like 'Related Topics')), and just clicking around the Web.

Finally, and not to be forgotten (ever!) is Omega Engineering, Inc., at www.omega.com. They publish some excellent volumes (big books!) on temperature and pressure and flow and level instruments that go into some excellent detail. I don't know if they ship internationally, but in North America they send books and/or CDs of this information for free! I don't know how much of their volumes are available on their website, but I would suspect a lot of it is, just maybe not in one reference location (though I could be wrong about that; I haven't checked before writing this). For information on just about any aspect of temperature measurement and control, pressure measurement and control, flow-rate measurement and control, level measurement and control, Omega publishes some excellent information.

I hope you find what you're looking for. Discovery can be a great and inspiring thing. Personal discovery can be even more inspiring.

If you have some questions about specific gas turbine-related applications, let us know.

 

CSA, don't you find that it's getting harder to find something on the web, even if you have a specific brand and model No, the first sites that come up are companies that want to sell you everything, including the kitchen sink. At least with Google anyway.

I second your comment on the Omega catalog, they are a great source of free technical information.

Regards
Roy

 

thank u everybody.... but actually Roy 's answer was useful ... also other advices are nice.
thanks a lot.

 

I wonder if Google algorithms don't look at the selections people make after they perform a search to determine what people actually find relevant (actually, I'm pretty sure their software does).

The Web has turned into a huge bazaar, where people look for information on where to buy this or that, and I think that's what Google has capitalized on (and in many senses even fomented, intentionally or not). I know that in the execution of my work tasks I use the Web extensively to get information, learn about suppliers and manufacturer's representatives, get (and give!) technical support, and generally participate in commerce on, and via, the Web. Any many of my colleagues and friends do so, as well.

So, I kind of think it's an almost logical extension of Google to move such links up in importance. I also think that many firms and companies employ people and/or other firms and companies to boost the relevancy of their sites and pages on Google, and I don't know if that's because Google permits such "lobbying" or if it's just that the system can be manipulated. I suspect it's a little of both. One has to take the bad with the good, of course.

I still use Google a lot, not exclusively, but it does turn up some very relevant links on occasion.

I see that Omega will ship internationally if the requester pays the shipping and handling.

Unfortunately, it's been my experience that in many parts of the world people don't earn enough money to pay for such "extravagances", and don't have a credit card to do so. What's even more upsetting is that employers won't pay for such "extravagances" even when it would improve the ability of their employees to troubleshoot, maintain, and even improve the reliability and availability of electrical power generation and production equipment.

One more personally disturbing thing is the availability of information on the Web seems to be contributing to the belief my many that everything should be free. Even by many employers, and not just outside of the industrialized economies. I've personally heard more than one plant supervisor say, "I'm not going to pay for something that should be free on the Internet!" But, they'll allow their employees to spend hours surfing the Web looking for information, and don't discourage the downloading of copyrighted material, and I'm quoting again, "It's available on the Internet! Why should I pay for it!" (Never mind that it was illegally posted on the Web to begin with!)

People who illegally post copyrighted material on the Web without proper permissions or attribution should be prosecuted to the full extent of international laws and made examples of, meaning they should have the "book thrown at them" and locked away for long periods of time if they can't pay the fines levied on them. Good, stiff, hard punishment, sufficient to discourage others from considering similar activities (though there are some who can never be discouraged).

 

You're right about the problems searching for information on the web using Google. But the use of terms like 'tutorial' or 'how ____ works' tend to bring up information, as opposed to sales hits.

Interestingly enough, John Dvorak, the PCMag columnist, recently published an article on the effects of Google's "search engine optimization" that emphasizes commerce over information, inability to identify a home site, parked sites, and unrepeatable search results.

http://www.pcmag.com/article2/0,2817,2334870,00.asp

A search engine that requires some thought to gain useful results is still no excuse for not trying a web search first.

Dave

 

In response to CSA: Search engines have to work with the information they find on a web site. The design of a web site can make a big difference as to where it turns up in a search engine ranking. The web sites of many of the automation vendors are very badly designed in that respect. They're also often very badly designed from the point of view of potential customers once they actually find the proper web site, but that is another issue.

Dealers doing business over the web on the hand tend to pay more attention to web site design. They go over their web site statistics in the same way that factory production managers go over their production line statistics.

One of the biggest mistakes is to put important information into Flash or into other forms of scripted data that can't be "spidered" but not provide an alternate conventional means of accessing the same information. Search engines index information by going out across the web and "crawling" through each web site. If a search engine gets to a web site where all it can "see" is just a blank page, then there isn't much it can do about it.

Generally, search engines will rank a well designed web site higher than a poorly designed one. I use "good" and "bad" from the point of view of finding information, not from the point of view of whether the web site looks like an art school project.

If you want a good example, the "Control.com" web site usually ranks fairly high in Google searches where it is relevant. Control.com uses very conventional web site techniques, which makes it very easy for a search engine to index.