Unless I'm missing something the question hasn't really been answered.
When you lift a carpet to blow air underneath you need to clamp it to the blower to keep the carpet under tension, as if it was still grippered to the outside of the room. As such the air blows underneath the carpet rather than creating a "flap" of carpet which prevents the blower from doing its job.
The clamp needs to be attached to the blower otherwise "clamping" the carpet will have no discernible effect.
As far as I am aware you need to buy the blowers with the clamp as an integral part. I am not aware that you can add a clamp at a further date. They work by folding the carpet in the corner of the room where you site the blower and it takes up the slack by folding over the part of the carpet where the blower is sitting. It works on a screw thread basis with a large "footprint" holding the folded piece of carpet in tension so that no crease is formed where the carpet is folded.
(I know what I mean by this description-I hope it makes sense to you guys.)
Try "Dri-Eaze". They sell the same blowers the same as Prochem (as far as I am aware) but for a fraction of the cost as they are not "Prochem" badged.