BONEGA® Antimagnetic Water-Meters and Accessories  

Protective Elements against Water-Meter Interference or Locking

1. Blocking against endless rotation (subtraction to minus)

The endless rotation of the water-meter’s counter was developed originally because of an easy tracing of the counter’s condition in various installation positions. At the most water-meters, this rotation can be, unfortunately, misused for subtraction to minus.

If no water flows through the water-meter, the turbine is stopped whereby it puts up a resistance. The counter rotation “in the right direction” causes the reverse run of the turbine, thus the aforementioned subtraction (the magnetic couple avoids the rotation of the main shaft at the counter). Many users succeeded in mechanizing it whereby they reach even some tens revolutions per minute.

To keep the possibility of an easy reading, avoiding the subtraction at the same time we have developed a gear that enables just limited rotation (670 degrees).
The easy solution consists in the innovated securing ring combined with a lug on the bottom brass part of the water-meter and with press-pieces on the side cover. The transparent polycarbonate cover and the opaque side cover are bounded undemountably.

According to the available information, the BONEGA^® water-meters are the only ones that have the aforementioned protection.

2. Unique antimagnetic resistance

As to the antimagnetic resistance, we supply the BONEGA^® water-meters in two designs:

• Water-meters without the antimagnetic resistance (labeled as T or S)
• Water-meters with antimagnetic resistance (labeled as TA or SA)

The difference consists in inside construction modifications that increase the antimagnetic shielding (antimagnetic resistance) significantly. It concerns de facto the internal antimagnetic cage, which consists of two specially modified inter-rings with high weight and size (see Fig.)

These modifications are done since a lot of unfair tenants try to affect the water-meters by means of magnets.
 

Detailed explanation

In the beginning, it has to be mentioned that thanks to higher reliability, dry-running water-meters are used almost solely at the flats.

On these water meters, the bottom part is not connected with the counter mechanically – by a shaft (as it is on the wet-running water-meters) but by a magnetic coupling. No seepages or even bigger water leakages through the upper regulating board menace (as it can be in the case of gasket wear and tear around the shaft on the wet-running types). On the dry-running water-meters, a pair or a tetrad of permanent magnets placed in the shaft usually ensures the motion transmission from the shaft to the counter. Opposite in the bottom part of the main shaft, there is usually another pair or tetrad of permanent magnets. As soon as the turbine starts to rotate, its magnets – under influence of magnetic forces – begin to “tear down” the magnets on the main shaft whereby the rotating motion of the shaft is transmitted onto the counter.
 

The most often misuse consists in application of permanent or other outside source of magnetism. After having been applied to the water-meter, it disturbs the magnetic field. In that case, the saccade or even the fully stop of the counter occur although the turbine still rotates.
 

Prevention

The manufacturers struggle to avoid the aforementioned phenomenon by means of various antimagnetic modifications. They show usually themselves on the higher bottom body, the protective cage inside a water-meter, thus they result in a no small increase in water-meter weight. For example, the weight difference between a ½” normal and antimagnetic BONEGA^® water-meter amounts to 15 g.

Range of the problem

It is an all-European problem that is proven by the European Union interest lasting several months. The European Union prepares the relating standard (EN 14 154-3) in which the required minimum resistance is mentioned at the rate 10 kA/m. There has not been stated any exact methodology yet, how this parameter can be measured exactly.

Methodology of the antimagnetic resistance measurement

How can you find out that the water-meters have the above protective ability? How can you measure that resistance? Which are the differences in this resistance between the individual water-meter manufacturers?
 

We put these questions to ourselves some years ago. Because the aforementioned standard is in the draft stage but the customers need to know the exact resistance, we have chosen the above solution.

The original used methodology was based on applying the permanent magnets to the water-meter. It was very difficult to define the parameters of such a magnet. Only a very inexact dimensional comparison was often used.

In 2003, we placed an order with the Slovakian Technical University in Bratislava to develop an as exact as possible measurement methodology based on the stepless control of magnetic flow which shall determine the value in kA/m exactly when a water-meter begins to measure (saccade of the counter), and the value when the measurement is fully stopped.

 Our basic preconditions:
1. To create a methodology for stepless measurement of the water-meter antimagnetic resistance which have to:

• define the repeatable processes clearly
• detect the influence of magnetism in tree various directions (horizontal, vertical and at a 45° angle)
• end with an output which has to include a concrete resistance value in kA/m which will define the condition when the inexact measurement begins (thus the saccade of the counter) and when the measurement is fully interrupted (counter stop)
• measure the antimagnetic resistance under the conditions similar to usual application, i.e. with the water flow-rate of the critical value which is 5 l/min (0,2 x Qn = 0,2 x 1,5 m3/h = 5 l/min.) and in the horizontal position of the water-meter
• do the measurement both within the magnetic field of ferrite permanent magnets and within the magnetic field in the air gap of the single-way electromagnet

2. To choose three best water-meters for the selection, based on our 12 submitted constructional varieties of antimagnetic modifications for the BONEGA^® water-meters

3. To do the comparison with a water-meter without antimagnetic modification, with a zero primary variety of an antimagnetic modification and with three varieties of the selection.

4. This measurement has to result in a recommendation for the best antimagnetic modification suitable for mass production.

After corresponding constructional modifications and tests, we have fulfilled our objective: to offer a household water-meter which is as resistant as possible in its magnetic properties and which has to withstand at least a pair of the biggest ferrite permanent magnets available on the market.

The BONEGA^® water-meters exceed the requirements
of the European standard by up to 1300 %.

• the testing was finished in the first half 2004 (the methodology and protocol are free for view) .
• the antimagnetic resistance modifications were done to withstand the influence of the heaviest permanent magnet known to us (even it is hardly available for private persons), which has the value 44 kA/m as a separate one and 72 kA/m in a pair.
• coincidentally, the performed methodology takes into account the same distance from the water-meter body (20 m) for one condition, as does the draft of the aforementioned all-European standard, so it possible to compare even today.
• the research of various varieties has resulted in an extraordinary high protection against magnetizing from outside, provided by the household water-meters BONEGA^® . The BONEGA^® water-meters exceed the requirements of the European standard by up to 1300% whereby they are ones of the magnetically most resistant water-meters in Europe.

Influence on price

Úprava má jen zanedbatelný dopad na zvýšení ceny.

Nowadays, we have appeared on the imaginary top of water-meters with the highest antimagnetic resistance.

The modification has only an insignificant affect on the increase in price. An additional and very expensive modification by the outside magnetic cage is not necessary more.

Difference between the BONEGA® water-meters with the antimagnetic resistance and without it

Conclusion:

• the antimagnetic resistance is an all-European problem
• as compared to the old methodology and the European standard draft, our method is much
  more accurate and balanced. It enables to determine exactly when the water-meter begins to lose through its inaccurate measurement and when its stops.
• thanks to it, the modifications executed on the BONEGA^® water-meters are extraordinary effective, they withstand even a pair of the biggest permanent magnets available on the European market (44 kA/m as a separate one and up to 72 kA/m in a pair)
• antimagnetic resistance of the BONEGA^® water-meters is on the worldwide top
• even the normal BONEGA^® water-meter (without antimagnetic modifications) hast its antimagnetic resistance higher than is that prescribed by the European standard draft (it has up to 16 kA/m)
• the installation of the antimagnetic water-meter is cheaper than possible additional outside modifications.

The Protocol on measurement is also available on a separate page because of its volume.

3. Protective opaque side plastic cover

The other possibility how to put a water-meter out of operation is to bore the dial cover on the side and to put an object through it, which locks the counter run. To choose the right place you have to see in –it is enabled by a transparent cover on other water-meters. This mechanical intervention is irreversible but unfortunately mostly little visible.

The BONEGA^® household water-meters have a side cover which is opaque and irremovably connected with the transparent cover of the device. It protects the counter device in mechanical and optical way.
 

4. Input screw joint sealing

Due to an unsuitable sealing, some water-meters can be dismantled or rotated by 180° without following recognition. The plastic pins can be “desealed” and again “sealed” with certain temperature, the copper wires can be drag out and string with a little practice.

Therefore, the return to traditional sealing with copper strands is recommended in the last time. The strand is to be drawn through the hole in the screw joint nut and through the sealing hole on the water-meter body. The ends are drawn through a lead sealing which closes and secures the strand ends against dragging out. After that, the registered mark is embossed into the sealing. To do this, the water-meter has to be adapted correspondingly.
 

Water-meters BONEGA®

• They enable to seal the input screw joint during the installation directly onto the formed lug with a hole on the water-meter body (the photo in the middle). It is possible to use a screw joint cap nut with “a hole” (the photo on the left) or with “an eye” (the photo on the right).
• in contrast to the only “winding” the strand round the body, this is a design of higher quality, which cannot be misused
• this solution makes the installation cheaper significantly (a short strand with sealing is enough)
• they enable to seal the inlet screw joint by a quality plastic divided ring with a pin seal (here is suitable only the screw joint without “eyes”)
• they avoid temporary dismantling or rotation of the water-meter by 180° and thereby the reverse run

5. Counter sealing

The water-meter is protected with a security ring with a seal avoiding the separation of the counter from the bottom part and therefore it is not possible to interrupt the continuous counting of water consumption, as it is possible with some water meters.

• The suitably technically solved ring secures a very closed and exact interconnection of the bottom body with the counter
• The ring also enables an easy sealing by a copper strand directly through a joint (lock) of the ring or just by sticking a sealing mark over it (the less secure way)
• Even after being sealed, the securing ring can be rotated freely (it still enables a comfortable detection of the condition)