[0001] Several versions of this type of pre-filter are already known and generally consist
of a housing and cover laterally fitted to a suction/force pump and provided inside
with a basket-shaped grille, the housing comprising a water inlet and lower down an
opposing outlet for the filtered water sucked by the pump. A pre-filter of this kind
is described in the US Patent 3,252,575. However, the pre-filters which have been
used until now have a number of problems, of which it is worth mentioning the poor
suction performance of the of the attached pump, imperfect filtration, difficulty
in opening (due to depression effects) for cleaning, and vibrations transmitted to
the ground where the pre-filter/pump assembly is fitted.
[0002] These pre-filters are fitted to a pump whose motor is cooled by the circulation of
water from the same prefilter wherefore the housing is fixed to the pump motor by
means of an intermediate yoke consisting of an element in which the pump wheel is
located.
[0003] On the face which abuts against the pre-filter housing, this circular yoke element
is provided with a cavity in which the pump wheel is located, whilst on the opposite
face the yoke element is provided with a central tubular trunnion in which the pump
axle is located by means of a suitable bushing.
[0004] The invention is characterised by the presence of various longitudinal channels distributed
about the circumference of said tubular trunnion in order to let in water for cooling
the pump motor, the water being driven towards it.
[0005] The invention is further characterised in that the outlet is situated on a lateral
cavity adjacent to the pre-filter housing, the yoke element being fitted to the mouth
of said cavity .
[0006] The cover consists of two elements, the cover itself and a screw collar by means
of which the cover is secured against the upper mouth of the pre-filter housing, and
with which arrangement the depression problem in opening the cover is solved since
the screw collar is removed first and then the cover can be lifted easily.
[0007] Another characteristic of this invention is that the pre-filter/pump assembly is
fixed to a base by means of elastic pads which eliminate the transmission of all vibration
to the ground.
[0008] It is also important that the handle of the basket-shaped grille forms an integral
part thereof.
[0009] These and other characteristics will become more apparent in the Detailed Description,
taken together with the three accompanying drawings which show a practical embodiment
which represents only one non-limiting example of the scope of the present invention.
[0011] Figure 1 shows a vertical section of the pre-filter housing and the yoke element.
[0012] Figure 2 represents a frontal view of the yoke element as seen from the face which
abuts against the prefilter housing.
[0013] Figure 3 illustrates, again in vertical section, the assembled pre-filter/pump arrangement.
[0014] Figures 4 and 5 show respectively a vertical section and a half plan view of the
pre-filter housing with the cover fitted.
[0015] Figure 6 is a perspective view showing details of the handle of the basket-shaped
grille.
[0016] As the drawings show, the pre-filter consists of a truncated, slightly conically
shaped housing
1 which forms an upper mouth receptacle
2 with an external thread
3 for the cover. The housing is provided with an upper, radially oriented water inlet
4, inside is fitted a basket-shaped grille
5 and at the bottom of the housing is a radially oriented purge orifice.
[0017] Opposing and below the water inlet
4, the housing is provided with an outlet
7 for the filtered water. This outlet leads to a lateral cavity
8 adjacent to the housing
1 at the top of which is located another outlet
9 through which the water passes to the outside.
[0018] A yoke
11 is attached and fixed to the mouth
10 of the lateral cavity
8 of the housing
1 and comprises a circular element
12 whose face
13 abuts against the housing
1 to form a peripherally threaded cavity
14 in which the pump wheel
15 of the pump
16 is located. The cavity
8 and the yoke element
12 are fixed together by means of their respective peripheral rebates
17 and
18.
[0019] On the face oriented away from the cavity
14, the yoke element
12 is provided with a tubular trunnion
19 in which one of the ends of the pump axle
20 is located by means of a bushing
21, wherein the axle is tubular and along its length runs the conduit
22 and wherein said face of the yoke element also comprises a peripheral rebate
23 for fitting to the housing
24 of the pump motor
25.
[0020] The aforementioned tubular trunnion
19 is provided with a number of longitudinal channels
26 distributed about its circumference and through which the water for cooling the motor
25 enters. The water is driven towards the motor, after cooling which it passes along
the conduit
22 of the pump axle to arrive at the cavity
14 where the pump wheel is located, passing then to the outlet
9 in the pre-filter housing.
[0021] The pre-filter/pump assembly is fixed to the ground by means of an interposed base
27 which supports it by means of elastic pads
28.
[0022] A cover
29 is fitted to the upper mouth of the pre-filter housing
1 by means of a screw collar
30 where said cover is advantageously transparent and has a diametric external protrusion
31 which may, if desired, include a depression purge orifice which can be closed by
means of a stopper.
[0023] In order to fit and secure the cover to the housing
1, the periphery of the cover is provided with an angular section and an underlying
rim
32 which fits into the internal periphery of the mouth of said housing, and an external
rim
33 which is seated on top of said mouth with an interposed o-ring seal
34. The cover is secured by means of an internal flange
35 on the upper edge of the screw collar wherein said flange presses against said rim
33 of the cover.
[0024] The basket-shaped grille
5 is stabilised within the housing
1 by the pressure exerted from above by a ring-shaped protrusion
36 provided on the inside of the cover
29, wherein the pressure is elastically maintained by means of the transverse handle
37 which forms a single piece with basket-shaped grille.
[0025] The handle consists of two flexible strips
38 and
39 which begin at diametrically opposed points on the port of the basket-shaped grille
and whose two free ends are fixed together by introducing a T-shaped projection
40 on one of the strips into an eye
41 in the other strip.
1.- A pre-filter for swimming pool installations of the type which consist of a housing
comprising a basket-shaped grille (5), closed with a cover (29) and laterally fitted
to a suction/force pump (16), the motor of which is cooled by the water sucked by
the pump, characterised in that this fitting is by means of an independent yoke (11)
whose face abutting the pump is provided with a tubular trunnion (19) which comprises
various longitudinal channels (26) to let in the water for cooling the motor (25)
of the pump (16), and that the water outlet (9) is provided with a cavity (8) laterally
adjacent to the pre-filter housing (1), the yoke (11) being attached and fixed to
the mouth (10) of said cavity (8).
2.- A pre-filter for swimming pool installations according to claim 1 characterised in
that the cover (29) consists of two elements, the cover itself and a screw collar
(30) by means of which the cover is secured to the upper mouth (2) of the pre-filter
housing (1) wherefore the periphery of said cover (29) has an angular section (32-33)
which fits into the internal periphery of said mouth (2) and which is supported by
it where it is forced by an internal flange (35) on the upper edge of the screw collar
(30).
3.- A pre-filter for swimming pool installations according to claim 1 wherein the pre-filter
is provided on a base (27) together with the pump (16) by means of interposed elastic
pads (28) provided for fitting the pre-filter housing (1) to the base (27) and supporting
the yoke (11) thereon.
4.- A pre-filter for swimming pool installations according to claim 1 wherein the basket-shaped
grille (5) comprises, and forms a single piece with, a handle (37) consisting of two
flexible strips (38,39) which begin at diametrically opposed points on the mouth of
the basket-shaped grille and whose free ends are fixed together (49,41).