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Pressing Matters

Tools & Accessories

Pipes can be connected in various ways. Probably the most popular connecting technology today is "pressing" because it saves time, involves no open flames and leads to a high-quality connection. 

For any press connection to be made successfully, pipes, fittings and the inlaid O or incorporated sealing rings are pressed together with a professional pressing tool. During this process, the pipe is deformed. This deformation can take a variety of shapes from hexagonal, octagonal, lemon-shaped or round. This is called the pressing contour. The final form largely depends on the size of the fitting but whatever it is, it ensures a powerful connection. The press tool has a pressing force of between 18 - 32 kN, depending on size, and through the application of this force, the sealing ring is compressed within the gap between pipe and fitting and ensures a tight seal.

Press fittings are designated by their appearance, their function, their size and the material:

  1. Appearance / function: e.g. bend, elbow, union, reducer, tee.
  2. Nominal Diameter: This is the outer diameter of the corresponding pipe (or name of the thread with threaded connections).
  3. Material: e.g. copper, stainless steel, gunmetal, lead-free silicon bronze...

In reduced fittings with outlets in different nominal diameters, these nominal diameters or thread designations must be given in the order shown in the diagram. Fittings whose outlets all have the same nominal diameters must be designated by stating this nominal diameter. 

Different press profiles, one solution

In addition, different fitting manufacturers have slightly different engineering tolerances and styles. This is called the “profile”. Typical press profiles for metal connections are “M“, “SA” or “V”. These are often system specific. SANHA however is the exception: Up to 54 mm we allow the use of all of the above press tool profiles (we call this tool compatibility, which is one part of our combipress feature). Once the fitting has been pressed onto the pipe, a small impression of the above profile is left on the fitting. This allows you to determine which profile has been used.

Before and after pressing

There are many components to, and variants of a press tool. In general, typical components are as follows:

The Press Gun

This is the main body of the tool, which generates the power needed to operate the jaws and collars which are individually attached to the gun. The guns can be battery or mains powered, and are of a hydraulic nature. The gun can be a sophisticated hydraulic tool, capable of storing press and service data, or a simple press-and-go version, and retail prices reflect the different levels of complexity.

Press guns can be battery or mains powered. The mains versions can be either 110 or 230V depending on the requirements of site. The battery tools, come in various sizes depending on the typical fitting sizes intended to be pressed. Larger battery-run tools can operate to 108 mm.

Jaws

These are similar to pincers, which are inserted into the head of the tool and secured with a locking pin. Due to the very high forces involved, the locking pin, must be closed in the safety position. The jaws tend to be used for smaller diameters, typically from 15mm to 34mm. The jaws are simply opened and closed around the fitting, ensuring the shape of the fitting fits into the opposite impression in the jaw. A small gap, between the tips of the jaws, will close on operation of the press gun, and form the press connection.

Collars or Slings

These are circular jaws made up of individual segments, which clamp around the fitting, leaving a round or lemon shaped impression on the fitting. The Collar can only be operated in conjunction with an “Intermediate Jaw”. Please check the SANHA installation guide for the correct configuration of jaws and slings. Collars can be held on with springs, we call this “Snap On“ or have a retaining clip and require securing.

Intermediate Jaw

This is a jaw which fits into the gun, and then clamps onto the Collar, rather than the fitting. By activating the Intermediate jaw, this in turn, closes the collar. For 108 mm only, two intermediate jaws may be required, depending on which tool you are using.

 

Maintenance

Like all tools, they work better when properly cared for. This can be a regular annual service, calibration or routine operational cleaning. The jaws can over time wear or become clogged up with metal residue and this must be removed. With collars, the segments must be clean and free to move. Poorly maintained tools can result in incorrect pressing and malfunction of the press system.

Press guns can be heavy and consist of moving parts, which therefore require careful handling. Always consider the best way of holding the gun, and be mindful of any health and safety risks associated with using such a piece of equipment.

Other accessories

Depth Gauge

These are an essential requirement for the installation process, and assists in ensuring the tube is inserted to the correct depth prior to pressing. The depth gauge is a tool which is used to set the marking point on the tube, prior to insertion. It can vary depending on the system used and product range, i.e. SANHA has one for Copper/Carbon and one for Stainless.

Tube deburrer

A tube deburrer carries out two functions. It can remove loose swarf left by the cutting process, and also lightly chamfer the end of the tube, which then assists in the insertion of the pipe. Sharp tube edges, can cut the O-ring in the fitting, if it catches on insertion, please exercise caution. Deburring the inside of the pipe, in addition to removing swarf, can reduce turbulent flow.

Lubricant

Sprayed light lubricant is best, if tube has become dry, as solid gel based lubricant can inadvertently, fill the O ring housing, and lead to a compromised press cycle.

Of course, planning, installation, commissioning and operation of facilities with press systems must be carried out according to the relevant standards and regulations as well as the manufacturer's technical instructions.

SANHA also run on-site installation training, covering all aspects of tooling. Please contact us today to arrange training and certification for your staff.