Wave Ball position

时间:2014-08-15 15:27:17来源: 作者: 点击: 0次

 The anchor position of the ball will be the result of a mix between the client’s wishes, the safety restrictions and the resonance simulation.

In practice, WOW asks since the beginning of the project the desired area where the client wants the Wave Ball to be placed. Once the final drawings of the pool are received and that everything is ok (depth, freeboards, filtration…) WOW makes a computer simulation in order to find the best place for the ball in the desired area.

Resonance frequencies computer simulation

The Wave Ball is working with the resonance of the pool so that the waves become higher and higher. For that, the Wave Ball has to be placed at a special location where its power will be used at its maximum of efficiency. In a wave shape, the blue points on the figure here below (fig 1) show where the ball can be placed. The green points are the nodal points where the ball has its minimum of efficiency (nodal points does not move vertically).

Fig 1: Ball position on a wave shape

Fig 1: Ball position on a wave shape

Each pool is different and has its specific resonance frequencies. Each resonance frequency has its specific wave pattern and thus places where the ball can be anchored. WOW has developed a simulation tool which can find those frequencies and show the nodal lines with the crests and troughs for each of those frequencies.

The figure below (fig 2) shows one of the results of such a simulation. The resonance frequency is 558.241 mHz. For example, the ball could be placed where the blue points are. In practice, WOW moves those points a little bit so that the same anchor position can allow the Wave Ball to use several maximum of various frequencies and thus several wave patterns.

Fig 2: result of computer simulation, wave pattern of one resonance frequency

Fig 2: result of computer simulation, wave pattern of one resonance frequency

Safety restrictions

The minimum depth

The Wave ball needs a minimum water depth to work. This depth prevents the ball to crash on the bottom of the pool while working. This depth varies following the model of the Wave Ball from 1.1 m until 1.8 m. (see pool design chapter)

The safety distance to the walls or to any fixed / movable accessories

The Wave Ball has to be placed at least at 3 m from any fixed object, this is to avoid a crash of the ball but also to avoid someone to be crushed between the ball and the wall for example.

Interaction with other accessories

Several interactions with other activities or accessories might reduce the possibilities for the Wave Ball placement (Pic 1).

Those are for example:

  • Evacuation route from the Huet
  • Reception area of the jump platform
  • Landing area of the parachutes
  • Solid life boat work area

Pic 1: The ball is placed where it does not interfere with other activities

Pic 1: The ball is placed where it does not interfere with other activities

The Wave Ball cable

(see also pool design and electrical configuration)

In some cases, the Wave Ball cable will limit the places where the ball can be anchored. This mostly happens with large pool and when the client wants to put the ball in the middle of the pool or far from the border. In that case, the cable might be too short to reach the border and thus the electrical cabinet. Ball has then to be moved to a place closer to the border.

In a general way, when there is only one place for the electrical cabinet around or under the pool, the place for the Wave Ball has to be chosen in such a way that cable is long enough to reach the electrical cabinet or at least the transformer cabinet.

The total available length of cable varies for each Wave Ball model due to the high current needed as the Wave Balls works in 12 volts.

From the W105FL to the W150F it is 25 m and from the W165FL to the W180F it is 17 m.

Fig 3: Cable length calculation

Fig 3: Cable length calculation

That maximum length is the total length of cable that can be used, if we take as an example the figure here above (fig 3), this length will be calculated as follow:

  • 3 m from the ball to the bottom of the pool
  • 2 m of free cable to let the ball move.
  • 3.5 m  to reach the border of the pool
  • 3 m + 0.5 m to join the beach level
  • 2.5 m to reach the wall where the electrical cabinet is fixed
  • 1.5 m + 0.5 m to reach the electrical cabinet and make the connections inside.

Total 16 m.

With that example, you can understand that the cable length can easily become very long.

In most rescue pools, in order to reduce the length of cable lost by going down and up to the bottom of the pool (pic 2), the cable weight is compensated by buoys in such a way it stays more or less at the surface of the pool (pic 3). In the example above, 6 m (2x3 m) of cable can be saved by choosing this solution.

Pic 2: Cable following the bottom of the pool

Pic 2: Cable following the bottom of the pool

Pic 3: cable buoy compensated

Pic 3: cable buoy compensated

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