IEC standard symbol for heating wire and exhaust valve.

Hello,

Hope this message finds you well and in good health,

I tried on google to see IEC standard symbols for the heating element and exhaust valve used inside a vacuum sealer, the ones that I found I was not pretty sure If they are correct to be used on PLC wiring diagram. Kindly could you indicate where I will be able to find the correct ones, please?

Thank you