The furnace in my house works great except for one huge problem. Every now and then, the pilot light goes out for no apparent reason. When this happens, I just relight it and everything is fine. Last week this happened 3 times. On one of the occasions I came home to a house that was 47 degrees. I have had my gas company out several times and they have replaced parts that looked questionable and cleaned other parts, but the problem continues. This has been going on for 2 years now, but is getting worse. Any ideas of what might be wrong?