French to English Law/Patents Patents Patent Application describing a vacuum packaging device from the 1960's

I cannot find a definitive English translation for this term in this context. "Capacity" just doesn't seem to fit. The text in this document is quite strange, and I am not perfectly sure as to why. Possibly it is a poor translation from another language into French. I was not given this information and since the document dates from the 1960's, I doubt the client knows whether or not it was translated from an original in another language.

The invention is packaging for animal food that is vacuum packed and resealable. The drawing with these reference numbers shows the envelope to be used for packaging the food in an apparatus to vacuum pack the contents (Figure is shown at the URL below).

I think it may be translated as "capacitor", but if anyone else has a better idea, please let me know.

Here is the context:
L'appareil de mise en œuvre est constitué par 2 capacités 13 et 14 disposées symétriquement à une distance l'une de l'autre réglable suivant la longueur de l’emballage souhaitée.

Les deux capacités 13 et 14 se prolongent chacune par un manchon creux 17 (et 18) possédant une rainure 19 (et 20) sur leur face extérieure cylindrique ou légèrement conique. La manche 21 coupée à longueur convenable est d'abord remplie de la quantité de nourriture 22 désirée, en séparant les rations de préférence.
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I have also uploaded the figure with items 13 and 14 as well as 17, 18, 19, 21, and 22 shown to help understand the context. Here is the URL:

http://tcrlist.com/13-14.jpg

I would appreciate any help you can give me.

Thanks,
Laura