There are several types of nozzles used in aluminum collapsible tubes. The major types are described below:
1. Conventional nozzles with more or less standard orifice sizes through which the product is dispensed. Typical of this type are the tubes commonly used for tooth paste, hand creams and similar products.
2. Nozzle where the threaded portion has an extruded rigid "canula" of small diameter. These are used where the areas of application of the product are specifically defined. Eye-ointment and veterinary tubes are typical examples.
3. Nozzle where the orifice is covered by a thin membrane of metal which must be pierced before the product can be extruded. Such tubes provide a hermetically sealed package and are referred to as "membrane seal" tubes.
4. "Taper" or "torpedo" nozzle tubes have no threaded portion at the nozzle area and require to be pierced with a pin before the product can be squeezed out. Certain adhesive tubes are typical examples.
5. Nozzle, canula, and orifice feature may be varied to suit particular requirements, provided. These are within the practicability of the impact extrusion process on a mass production basis.
6. Plastics nozzles attached to metal tubes. These are special innovations which have found increasing use (especially where abrasion between the tube closure i.e. cap and the conventional metal nozzle produce a blackening of the product). In other instances a plastic elongated nozzle affixed to the tube is often used where the application of the pharmaceutical or veterinary product requires the tube canula to be brought almost into contact. Certain veterinary cerate tube with canulas are used as one shot dispensers where cerate is introduced into, for example, the udder or uterous of animals for treatment of mastitis or intrauterine treatment. These nozzle are attached to the tube by mechanically crimping it to the shoulder, or by spinning metal round the molded plastics nozzle, or by injection-molding it, directly over a metal nozzle of specified conformation.
7. Although tubes embodying various ideas for a captive closure were tried over a period, none completely solved the problem. First ideas were based on attaching the cap by some mechanical means to the metal nozzle of the tube. Although this solved the problem of cap loss, it did not eliminate the problem of abrassion resistance between the metal nozzle and the cap, which result in discoloration of the product. It is possible to apply a plastics nozzle portion to a tube and to fix a captive closure to it without the necessity of having the nozzle threaded in any way.