Pressing tools: selection and care
In the pressing technique, a solid connection is created by joint radial deformation of the fitting and the pipe. The sealing function against release of the pumped medium is performed by an additionally inserted sealing ring made of elastic plastic (elastomer).
One special features of our metal press fittings is their design and manufacture, aka "combipress" (more on that later). They allow reliable installation and ensure permanently tight connections. During the development of all systems, the focus was on ensuring that all press jaws and press machines used for press connections, type M-MM (mechanical connectors made of metal for metal pipes), can be approved. A possible mix-up of the pressing jaws - which can easily happen during the hectic construction work - therefore does not represent a safety risk with SANHA® products.
The pressing tools listed below are suitable for all metallic pressing systems, provided that the care and maintenance instructions are observed, in order to produce a permanently tight press connection.
General information on press tools
Press fitting, pipe, press jaw and press machine are always matched to each other in such a way that the interaction of these four components results in a non-detachable, form-fitting and longitudinal force-fitting, sufficiently pressure-resistant joint. On the other hand, this means that the tolerances to be absorbed by the system must be distributed among the components.
For all press fittings and stainless steel tubes, SANHA® ensures even very tight manufacturing tolerances. Copper pipes according to EN 1057 - as these must be suitable for the capillary soldering technique - also have very tight tolerances. This means that the perfect functioning of the pressing jaw and the pressing machine is of particular importance. Worn pressing jaws in particular, but also pressing machines that no longer function properly - because, for example, the pressing stroke has become misaligned over time - can therefore lead to joints that are not sufficiently secure.
Both pressing jaws - which inevitably wear out in the course of operation - and pressing machines must therefore be subjected to regular functional checks. Basically, all pressing jaws as well as all pressing machines should be serviced at least once a year, unless other maintenance intervals are specified by the manufacturer.
In order to achieve a permanent and safe pressing, pressing tools can be used up to and including the dimension 54 mm, which generate a linear pressing pressure of at least 30 kN during pressing.
If significantly higher linear pressing pressures (e.g. over 34 kN) occur, the pressing jaws could be damaged (caution, risk of injury!).
The pressing machines and pressing jaws or slings can be used for pressing metallic SANHA piping systems if they are in technically perfect condition, the inspection and maintenance intervals specified by the manufacturer have been observed and both machines and pressing jaws or slings are used in accordance with the manufacturer's operating instructions.
Each SANHA® press machine is provided with a round maintenance sticker. The marking on this plate indicates when the machine must next be sent to the manufacturer or a specialist workshop authorised by him for maintenance.
With regular maintenance (once a year), the warranty period for the press machine is increased to 3 years.
Pressing machines from other system suppliers or machine manufacturers must be checked or serviced according to their specifications. If no manufacturer's specifications are available, the inspection must be carried out at least once a year.
Press jaws and slings are subjected to strong oscillating forces. In extreme cases this could lead to material fatigue, or at least to significant wear - especially of the bolts. In order to safely rule out dangerous accidents, there are two viable options here:
1. Regular maintenance of press tools:
Here, all worn parts or even deformed parts are replaced so that after this maintenance, the plumber has a press jaw or slings that is as good as new.
2. Limiting the service life:
The other way to prevent accidents is to attach a predetermined breaking point to the pressing jaw in such a way that the pressing jaw is destroyed after a certain service life and can thus no longer be used.
Care of the pressing jaws and slings
On the construction site, it is unavoidable that pressing jaws and loops become dirty. Likewise, a coating consisting of metal abrasion forms on the surface of the pressing contour over time, which significantly increases the friction between the metal surface of the fitting and the surface of the pressing jaw. This deposit should be removed with e.g. a metal-free fleece (catalogue no. 961) in combination with a solvent such as methylated spirits.
In addition, oil the hinge points in the area of the bolts to reduce wear. Then spray the entire jaw with a rust and corrosion protection. In the case of the press slings, graphite oil must also be sprayed between the sliding segments and the press shells. The segments must always be able to slide freely. Finally, clean the contacts on the pressing jaw and intermediate jaws for electronically controlled pressing machines (catalogue no. 6920 or 6931).