Wireless temperature measurement/logging

[epoxyman]

Our application requires temperature measurement and logging, on up to 24 separate products simultaneously, for up to 12 hours. We currently use thermocouples wired to a name brand data logger/software/pc arrangement. The system works well and easily meets our technical requirements. Our product is fairly large, and is processed in a relatively confined space. The tc’s are attached to each product after it has been moved into position by crane. After all are in position and prepared, the whole lot is subjected to thermal treatment for up to 12 hours. The tc’s are removed after thermal treatment, and then the products are removed from the area with the crane. The tc’s lay on the floor of the area until the next day where the whole cycle is repeated.

The average line of site distance between products and data logger is approx. 60 ft. The tc wire length between product and data logger is approx. 120 ft. The products’ temperatures can reach up to 450°F. The air temperature below the product reaches a max. approx. 150°F.

Due to the confined workspace, I have been asked if the tc’s could be attached before the product is moved into position. That is where the wireless devices would come in. I have at least the two following scenarios:

1) Attach tc and transmitter to each product before moving into treatment area. The tc would be the input to transmitters that hang below the products. The transmitter’s signal would be sent to a receiver that has an output that could be read by the existing data logger.

2) Same as #1, except use a different data gathering device in place of the existing data logger.

This is a manufacturing facility, and costs are always a factor in this type of situation. But cost is not the only factor, just a close second. Any suggestions and/or leads are greatly appreciated.

 

[saxon]

epoxyman, There is a local wireless technology for instrumentation & control called "Bluetooth". Check the following website,

http://www.bluetooth.com

saxon

 

[ICman]

That 150F ambient might be a little high for your transmitters. It will surely shorten their life.

Can you use infrared measurements? Or, a "thermocouple concentrator" (for lack of a better term)? These are non-contact devices, but would only be good if your product is placed in the same relative position each time. They would pick up surface temperature.

How are the TCs "attached"? Weld/solder? Glue? Mechanical? Are you trying to measure the temperature of the product (up to 450F) or the environment (150F max)?

Then, how about the possibility of a "disposable" TC? This could be (permanently?) attached to the product, and a simple plug-in could be used to connect it to your data scanner. You would either ship the product with the TC attached, or remove it and throw it away after testing/treatment. Cost is maybe $2 each, or less.

Just some ideas ...

 

[epoxyman]

ICman,

The equipment is placed in the same relative position each day, but we have several sizes, metallurgies, and surface finishes. It makes the use of infrared sensors less desirable compared to tc's. We use band clamps to attach the tc's to the equipment (equipment is round). We measure product temperature up to 450°F. The location where I want to place transmitters reaches up to 150°F max.

Thanks for your suggestions.
Epoxyman

 

[hacksaw]

the short answer to wireless transmitters is that it would be costly. the service temperatiure is prohibitive.

high temp devices are possible, but either special order or proprietary. the oil field (down hole ) industry specializes in high temp devices. expect serious cost issues, it is not an easy design matter.

you might considetr using fiber-optic temperature sensive.

it is IR based, but does not have the difficulties associated with sighted devices. you will still need a clamping devices.

 

[ICman]

Okay, how 'bout this?

Use TCs with plug-in heads: ---{ Attach the TC to the product, load the product(s), plug in cable with matching socket: }--- going to your data gathering system. When complete, unplug TC and remove once it's out of the oven.

The plug-in head is used a lot for laboratory work, but I believe it's capable of withstanding your temperatures. Your time in the confined space would be limited to plugging in the connectors.

 

[joecontrol]

look for a company called KIL_TEL they mak a wireless thing for shuttle kilns. I may work in you situation. I think they are out in seattle,wa

Joe

 

[joecontrol]

I had a better thought. National instruments

http://www.ni.com

maks a fieldpoint module for tc and it can be set up as a wireless node on a network. You might be able to run it off of a battery set up and not have any wires attached to your computer equipment. Just a thought. Ask if you have more questions.