[0001] The invention relates to a pool or water tank provided with means for generating
waves.
[0002] Various methods are known for generating waves in swimming pools or water tanks for
fish or mammals. One of said methods comprises supplying compressed air in turn to
chambers which are closed at the top and at the bottom protrude into the water in
the pool or tank. If the compressed air is introduced into the various chambers at
the natural frequency of the pool, this method requires relatively little energy,
but the major drawback is that the tank or swimming pool has to have an adapted, relatively
expensive design.
[0003] In the case of a second known method, a ball which has a weight which is movable
up and down therein floats in the middle of the tank. A ball of this type takes up
a relatively large amount of space and must be able to be suspended from the ceiling
by a hoist construction. Moreover, a long electric cable to the ball is needed underwater,
the length of said cable being subject to regulations.
[0004] Furthermore, it is known to move part of the floor of a swimming pool. This involves
an expensive structural facility which is usually unsuitable for existing pools or
tanks.
[0005] The aim of the invention is to overcome the drawbacks of known pools or water tanks
which have wave mechanisms and to provide a pool or water tank, indicated in the preamble,
for which the means for generating waves are simple and relatively inexpensive and
can be installed in existing pools or tanks without special structural facilities
(apart from possibly raising the height of the walls of the pool or tank). Moreover,
the wave facilities must not give rise to obstacles for swimmers and there must be
no cables or leads present in the pool or tank.
[0006] According to the invention, the pool or water tank provided with means for generating
waves is characterised in that said means comprise one or more pipes, each of which
is connected, at least at both ends, via a hole in the wall of the pool or tank, to
the pool or tank, wherein a piston or disc which essentially closes off the cross-section
of the pipe is fitted in one section of each of the pipes and a power source is present
in order to move the piston or disc backwards and forwards.
[0007] DE-A-2811623 describes a swimming pool wherein a niche filled with water adjoins
one of the sides of the swimming pool, is in open communication with the swimming
pool and is divided into three chambers by means of two partitions. The two partitions
are each connected by means of a rod to a piston which is movable in a hydraulic cylinder.
Waves can be generated in the swimming pool by moving the two partitions by means
of the pistons. This construction requires expensive structural facilities and is
not suitable for adding to an existing swimming pool as a recreational element in
a simple manner.
[0008] Preferably, the length of the pipes corresponds to at most half of a resonance wavelength
of the water in the pool or tank.
[0009] In practice, each pipe will be provided on either side of the central section, in
which said piston or disc is movable, with two or more channels connected to a hole
in the wall of the swimming pool.
[0010] The cross-sectional area of the channels will have to be greatest at locations where
the amplitude of the wave is greatest, and vice versa. Therefore, the cross-sectional
area of the channels will be greatest at the ends of a pipe and that of the channels
at the side of said means will be smallest and the cross-sectional area of the channels
will decrease from the largest channel to the smallest channel.
[0011] If various pipes are used, the power sources will operate in phase with one another
but in opposing directions of flow.
[0012] The invention also relates to a wave installation to be used in the abovementioned
pool or water tank.
[0013] The invention will now be explained in more detail with reference to the figures.
Figure 1 shows a top view of part of the pool or water tank;
Figure 2 shows a side view of the pool or water tank according to Fig. 1; and
Figure 3 shows a cross-section of a possible connection of an orifice of a pipe opening
into an opening in the side wall of the pool or tank.
[0014] The walls of the wave pool or tank shown are indicated by 1. Two wave installations,
each consisting of a pipe 2 having a central section 3 and two connecting sections
4 fitted on either side thereof, are installed on one side wall. A piston or disc
5, which essentially closes off the cross-sectional surface area and can be moved
backwards and forwards by means of a piston rod of a pneumatic cylinder 6, is fitted
inside the central section. The connecting sections 4 each have three inlet and outlet
channels 7a, 7b, 7c, which are connected by flange connections to openings 8a, 8b,
8c in the side wall of the pool or tank.
[0015] Figure 3 shows the flange connection between a channel 7a and the side wall of the
pool or tank. A pipe 9 is fixed by means of resin in the opening 8a to provide a seal.
Said pipe has a flange 10, which is fixed by means of bolts 11 to a flange 12 of the
channel 7a.
[0016] The length of a pipe 2 corresponds to at most half the resonance wavelength of the
pool or tank. The two pipes shown generate waves which have twice a half resonance
wavelength. The one pipe operates in the same phase but in the reverse direction of
flow to the preceding pipe. The shape of the waves is shown by a broken line in Figure
2.
[0017] The channels 7a and the openings 8a at the ends of a pipe 2 have a larger cross-section
than the channels 7b and openings 8b, which, in turn, have a larger cross-section
than the channels 7c and openings 8c. Consequently, the size of the cross-section
follows the size of the wave amplitude.
[0018] Of course, the first impulse will take a great deal of power, but as the wavelength
of the generated wave follows the resonance wavelength of the pool or water tank,
it becomes increasingly easier.
[0019] The installation according to the invention has considerable advantages. It is easy
to install. No structural facilities are needed for wave generation. It may be necessary
to raise the height of the sides of the pool or tank, or the water level could be
lowered. The apparatus can be fixed to the outside of existing pools or tanks by simply
drilling a few holes in the wall of the pool or tank. The apparatus does not constitute
any obstacles for the swimmer and there are no cables or leads through the area. It
is very suitable for use in tanks containing mammals or fish and produces no noise.
1. Pool or water tank provided with means for generating waves, characterised in that
said means comprise one or more pipes (2), each of which is connected, at least at
both ends, via a hole (8) in the wall of the pool or tank, to the pool or tank, wherein
a piston or disc (5) which essentially closes off the cross-section of the pipe is
fitted in one section of each of the pipes and a power source (6) is present in order
to move the piston or disc backwards and forwards.
2. Pool or water tank according to Claim 1, characterised in that the length of the pipes
(2) corresponds to at most half of a resonance wavelength of the water in the pool
or tank.
3. Pool or water tank according to Claim 1 or 2, characterised in that each pipe (2)
is provided on either side of the central section (3), in which said piston or disc
(5) is movable, with two or more channels (7a, 7b, 7c) connected to a hole (8a, 8b,
8c) in the wall of the swimming pool.
4. Pool or water tank according to Claim 3, characterised in that the cross-sectional
area of the channels (7a) at the end of a pipe is the greatest and that of the channels
(7c) at the side of said central section (3) is the smallest and any channels (7b)
decrease in cross-sectional area from the largest channel to the smallest channel.
5. Pool or water tank according to one of the preceding claims, characterised in that
if various pipes (2) are used, the power sources (6) operate in phase with one another
but in opposing directions of flow.
6. Wave installation intended for the pool or water tank according to one of the preceding
claims, characterised by a pipe (2) to be connected at both ends to a hole in the
wall of a pool or water tank, which pipe has, in one section, a piston or disc (5)
which essentially closes off the cross-section of the pipe, and a power source (6)
in order to move the piston or disc backwards and forwards.
7. Wave installation according to Claim 6, characterised in that the pipe (2) is provided,
on either side of a central section (3), in which the said piston or disc (5) is movable,
with two or more channels (7a, 7b, 7c) to be connected to a hole (8a, 8b, 8c) in the
wall of the pool or water tank.
8. Wave installation according to Claim 7, characterised in that the cross-sectional
area of the channels (7a) at the ends of the pipe (2) is the greatest and that of
the channels (7c) at the sides of said central section (3) is the smallest and any
channels (7b) decrease in cross-sectional area from the largest channel to the smallest
channel.