Thursday, December 10, 2009

The pressure is on!

Middle Tennessee Gas Company came out in the rain and put pressure gauges into the system at several places. One before the regulator, one after the regulator before the meter, one right after the meter and another where the line change to 1/2 inch piping. Now with the two gages I have at the burners, that makes 6 gages in total. What fun for an engineer!

Took just a minute of running the system to determine that the orifice in the regulator was too small. It took just another minute for them to replace it. The pressure at the burners is where it was designed for.

Now, it is time to make some ware and see if it will reach temperature. [It also has to get warm enough so all my clay isn't frozen solid]

Wednesday, December 02, 2009

Close, but no cigar

The gas company's contractor and installed the new flow suppression device. I was banging away on my computer when I heard the backhoe.

The device is really nothing more than a spring and a ball. In the small one that was in there, you can blow into the end and make it close.

The scale of the photos distorts the difference in size. The new one is about 4 times as large. You can blow yourself blue; you won't get this one to close.

I was curious about how they connect the pipe. It is welded using "irons" that they heat to about 450 degrees.

They have mechanical guides the bring the pipe together once they apply the heat to it. Makes sense, just never seen it done before.

The whole process of changing out the device took less than an hour.

After they had the new device installed, I fired up the burners for another test. No shut down, but it still is not developing they pressure I want. My guess is that we have the kiln piping undersized and are not getting the flow needed. The gas company is coming out next week with pressure gages and we are going to troubleshoot the system. I think I will run some numbers and give Ward Burners a call.

Tuesday, December 01, 2009

That's why you do tests

Been off on a trip to Florida to help my daughter move and attend a family Thanksgiving reunion. It was fun, but now its back to kilns and pots. I was inspired by a stop to the Clay & Paper gallery in Dunedin, FL. I got to see a number of potter's work including McKenzie Smith's. I took a workshop of his acouple of years ago and I really enjoy both him and his ware.

The test went well up to the point where I tried turned the burners up to full operating pressure. I turned up one burner and was only able to get 5 psi. I tried to turn the other up and the pressure on the whole system dropped to less than 0.5 psi. I shut the system in and went away for about 30 minutes and then tried relighting pilots and burners. They worked as before the drop. I slowly turned both burners up and when I got to 4.0 psi on both burners, it shut in again. Had to be a safety device on the line. I checked with the engineer at the gas company and he said it could be the regulator or a federally mandated flow suppression device that was under sized. They are due here in a little while to dig up the line at the connection to the town supply main to replace the flow suppression device with a larger one. Then they want to run the burners at maximum pressure to verify that was it. I am warming the kiln just because I am a little nervous about throwing that much heat at a cold kiln.

Hopefully, this will get me my 6 psi design operating pressure.