Food Dehydrator - tech question on thermal fuse

I have a Nesco unit, after 20 months the thermal fuse went, I ordered some and replaced it, but now it seems to have blown again, after about 3 or 4 sessions later. Is anyone familiar with these, and how to maybe eliminate this issue? Bigger Thermal Fuse, or is it a thermostat issue?
It seems in looking at reviews, this is a common issue with several brands of food dryers, including the $200+ units out there.
Some reviews would have one afraid to leave the thing running unattended, which defeats the purpose of the whole 'heated air dry' process.

Thanks - Tim

TimSue,      Electrical stuff not my forte.  Hope you can get some help from knowing folks.

I suspect it is that the heating elements electrical resistance , it  is made as a single rating so it will cover USA voltage 110 volts '60 cycles per second and also the rest of the world  that uses 220, 240 and 250 volts @ 50 cycles per second .

 When you use it on 110 volts the current drawn becomes higher than when you use 240 volts  to get to the heating element same temperature , this makes for excessive heat through the fuse which over a fairly short time will cause it to blow.

 Quite often these mass produced made in China under contract or bulk buys from that part of the world suffer from this little problem.
 
 The mathematics of electrical engineering  mean that the thermal fuse will run hotter on the fuse thus be prone to blowing .
 Though that said a lot of thermal fuses reset themselves when left switched off and go cold .

 If you are competent enough to change the fuse to an American made self resetable one of the same value  .....you may /may not cure the problem.
 

 If i were you I'd  look to source a made in USA produced /manufactured  dehydrator ( Can get them ??? ) and pay up the extra for the quality and reliability.