Let me help you with some terminology.
The thing Inside the Box on the firewall is called an evaporator, the canister is an accumulator drier, the lines to the compressor and condenser are called refrigerant lines,
what looks like Radiator in front of the radiator, is a air conditioning condenser.
The orifice tube is named improperly.
it's an orifice that fits inside of a tube.
The refrigerant line coming from the condenser leads to the evaporator. when you first look at it you think it goes into the bottom of the accumulator but it doesn't. The orifice fits in the tube at the bottom of the evaporator. This is where the orifice will be, you'll need needle nose or a special tool to pull it out. they are plastic and hard to get out because they get driven into the tube from the high-pressure refrigerant. You will most likely replace it with a blue orifice.
While you are doing all this, you want to make certain that your fan clutch, fan, radiator and condenser are in top condition. if you don't HEAR the fan when it's hot out, it means a fan clutch may not be working right and your air conditioning will not cool properly.