When working with pipes, the demagnetisation process requires that cable is wound around the pipes. Typically 20-50 turns are required. In some situations, such as production and pipe laying environments, the time taken for the winding process can become significant.

The ZMCC has been designed to provide a fast and effective solution for this problem.  In use the Clam Coils are placed around the pipe and the connectors brought together; a cam driven mechanism is used to draw the 25 connectors together in a quick single action.  Now just plug into Zeromag and you’re ready!

Clam Coils are usually deployed in pairs one on either side of the joint as shown in the above picture.

The Clam Coil is available in a variety of formats depending on the application.  It is normally supplied as 25 turns of cable with an array of connectors capable of carrying more than 100A.  The cable connect array has a full wiping action to ensure good clean contact for the 2500A total current through the device.

The forces required to mate and detach the connector array are high, and to make it easy to use, the cable clam has a cam mechanism.  This allows deployment to be carried out in seconds by one person. It is supplied with leads to connect back to Zeromag and storage case.

For Zeromag to null a magnetic field it must first be able to measure it.  The ZM2PG is a robust stainless steel probe designed for the harsh welding environment. The probe plugs into Zeromag and can be zeroed prior to measurement of the field in a the weld prep. In automatic nulling mode it traverses the weld, just ahead of the weld position.  An air (or inert gas) line is connected to the manifold and gas flows through and out of the rear of the probe, away from the weld, to keep the sensor cool.  The ideal gas pressure is 2 bar, a pressure relief valve on the manifold protects the probe from over pressure.

The probe is a key part of  the Zeromag system and, while robust, it can be damaged.  So to avoid project delays keeping a spare probe is recommended.

For larger pipes, or for giving more convenience in positioning of Zeromag,  3m probe extension cables are recommended.

Zeromag controlled by ZM150 degausser is used to degauss pipe joints at fit-up, or pipe ends prior to fit up.  For degaussing to be successful a field must be established that magnetically saturates the steel.  The maximum field achieved for a particular demagnetizing current depends on the pipe diameter (as this determines the number of turns), the wall thickness and the type of steel.  For a standard Zeromag ZM100A joint degaussing is usually possible for pipe diameters to about 16 inches (0.406m).

To increase the degaussing power the dual degausser ZM150x2 provides all of the features of the standard ZM150 but controls two Zeromags.  So the degaussing power is 3kW with two standard ZM100A, 4.5kW with a ZM100A-33 and ZM100A or 6kW with two ZM100A-33.  These higher powers allow joint degaussing on larger pipes and thicker walls.  The table below shows a rough guide to the pipe OD for a particular Zeromag power and wall thickness for achieving 1.5 Tesla in the steel. This is for a standard carbon steel but do note that the degaussing efficacy will depend on the details of the job, in particular the pipe steel, OD, wall thickness and cladding.

Clam coils are recommended for rapid deployment of sufficient demag turns, the number of clams required will depend on the pipe size and degaussing power available, contact Diverse for advice. Clam coils can be connected in series and are available as single wrap (25 turns per clam) or double wrap (50 turns per clam).

Zeromag measures and neutralizes magnetic fields which may be present in the weld preparation region of mating steel components.  When welding pipes there are several ways of working. In normal operation, Zeromag is used to dynamically reduce the magnetism during welding.  This works well but having demagnetizing components in place while welding can hinder welding throughout.

The ideal would be to degauss all the components completely, but the process is too long and cumbersome.  There are also issues with penetration of ac degauss fields into the bulk of the material, leaving the core still magnetized.

The Zeromag degauss option undertakes degaussing of the complete fitted up butt joint.  In this mode of operation cable is wound over the pipe butt joint (usually with clam coils) and a quick downcycle initiated.  With the joint degaussed the coils are removed and welding can commence.  Magnetism can return either over time or as a result of the changes in magnetic geometry as welding progresses.  If this occurs the demag procedure can simply be repeated.

The joint degaussing can be extended to pipe end degaussing.  In this mode, the Zeromag degauss option undertakes degaussing of the end of the pipe only prior to fit-up.  This down cycling process is relatively quick – typically less than 3 minutes. The hysteresis loop time is typically 10 seconds allowing deep penetration of the degaussing field into the steell of the pipe end.  The magnetism in the rest of the pipe remains unchanged, so, over time, the magnetism in the rest of the pipe will ‘leak’ back into the pipe end.  This process is material dependent, but is typically about 1 hour.

The dual degausser controller ZM150x2 is available for controlling two Zeromag, this is used for degaussing larger pipes and thicker walled pipes.

Zeromag ZM100A is used world wide by leading welding companies to overcome arc blow. When working with pipes this process requires demag cable to be wound, typically 20 to 25 turns. Winding can be a slow process typically occurring after fit-up. Split bobbins offer the opportunity to wind the cable off line;  bobbins and cable are then passed over the pipe end prior fit-up. Often these are used one either side of the weld preparation. Eye-bolts on  the bobbin facilitate hoisting of the cable and bobbin assembly.

Once welding is complete cable can be quickly pulled off the bobbin. Thumb nuts are then loosened and the bobbin can be split for removal from the pipe. The process is then repeated for further joints.

Split bobbins are aluminium construction and manufactured to pipe size, specified at time of order.

The Diverse Zeromag measures and neutralizes magnetic fields which may be present in the weld preparation region of mating steel components.  When working with plate or pipes, the demagnetisation process requires that the magnetic field is controlled via the demagnetizing cables.  This works well when the object can be coiled around with the cables but for large diameters or plate applications lay on coils are used.  These are cumbersome to deploy and magnetic coupling is not as effective when the coils do not go round the work piece.

For high fields the most efficient way to null the magnetic field is to use ZeroZone. This is prewound with 40 turns and provides a magnetic bridge across the weld prep to allow control of the magnetism.

In operation, ZeroZone is placed across the weld prep.  The arms and pole pieces are adjusted so that the active area of the pole pieces are in close contact with both sides of the work piece.  ZeroZone is then connected back to Zeromag and the system used as normal.  ZeroZone is particularly effective with Zeromag operated in automatic or manual nulling modes

Once the magnetism is nulled, welding can commence.  The nulling effect of ZeroZone extends along the weld preparation outside the region of the ZeroZone jaws.  In automatic mode ZeroZone can be clamped in position and the welding can progress over an extended range without the need to move ZeroZone.

For large pipes, a Zeromag and ZeroZone each side of the pipe allows two welders to weld unimpeded regardless of the type and level of magnetism in the pipes.

Zeromag ZM100A is used world wide by leading welding companies to overcome arc blow.  The ZM150 degausser in conjunction with the Zeromag ZM100A is used to demagnetize pipe-ends prior to fit-up, or joints post fit up.

Successful degaussing of pipe-ends requires the application of fields large enough to magnetically saturate the steel.  The magnetic field required depends on the type of steel, the number of turns, the current and the ratio of pipe diameter to coil length along the pipe.  Thus there are a variety of conditions that determine whether the saturation magnetic field is reached. Generally for most steels a pipe diameter of less than 28” (0.7m) will be saturated using Zeromag.

Turns can be applied to the pipe end by manually winding the 50 m demag and 50m demag extension cables supplied in the standard package (DKPW).  This is time consuming and not always convenient.  The Zeromag bobbin applies 100m of cable turns repeatedly and rapidly to the pipe-end.

Connection cables are supplied to connect  the bobbin to Zeromag. Bobbins can be supplied for any user defined pipe size.

For degaussing larger pipe ends two bobbins, connected in series, can be used with the high power Zeromag ZM100A-33.