Centrifugal pump for water recirculation

Abstract

 The invention relates to a centrifugal pump for water recirculation. In order to overcome the difficulties in cooling the seal of such a pump it is provided that the pump body, which forms a part with a prefilter (2) is linked to the electric motor housing by a markedly truncated cone-shaped shield (15).

Description

[0001] This invention refers to a centrifugal pump for water recirculation, particularly applicable to swimming pools, of the type comprising a centrifugal electropump, a prefilter and a pressure chamber between both. The electropump is fitted with an electric motor whose shaft moves a multi-vane impeller which turns inside a diffusion chamber, partly sealed by a diffuser, with the liquid entering coaxially to the impeller and being dispatched by centrifugal force to a pressure chamber provided between the electric motor and the prefilter. The prefilter is so arranged as to comprise a vertical filter bowl, fitted inside an end bowl sealed hermetically by an externally threaded cover and provided with an external intake mouth and an outlet pipe connected to the axial inlet of the impeller, so that the intake liquid is forced to pass through the walls of the afore-mentioned filter bowl before reaching the electropump.

[0002] In this type of centrifugal recirculation pump, particularly for swimming pool water, a serious problem often arises which consists in the enormous difficulty of cooling the mechanical ceramic seal placed between the impeller and the driveshaft.

[0003] This problem is overcome on the pump in question, the main feature of which is that the pump body, which forms a single part with the prefilter, is linked to the electric motor housing by a markedly truncated cone-shape shield. The pressure chamber and the electropump are hermetically separated by a double-tapered spacer with a centre hole and arranged so that its outer edge is trapped. An 0-ring seal is placed between the respective contiguous edges of the above-mentioned connecting shield and the pump body, while the edges of the centre hole hold the conventional mechanical ceramic seal of the impeller.

[0004] According to another feature of the invention, the impeller shaft is provided with a hollow cylindrical extension, adapted for fitting on the electric motor shaft and of a length such that its inner end is positioned between the mechanical seal and the electric motor.

[0005] In accordance with another feature of the invention the inner edge of the diffuser engages in the linking edge of the two cones of the biconic spacer.

[0006] The markedly biconic-shaped spacer, preferably of stainless steel, offers various uses or applications. The most important of these is to act ad a heat sink when the pump is working with a water flow below its rating. It also acts as a support for the mechanical seal.

[0007] Furthermore, a great advantage of the centrifugal pump in question lies in the fact that the biconic spacer, on the wall of the inner cone, is provided with at least one shoulder for causing swirl in the water crown while the impeller is working in order to improve the cooling of the mechanical seal.

[0008] We may also mention the great ease of assembly and disassembly of the pump in question in respect of similar ones already well known.

[0009] Other features and advantages of the centrifugal water circulation pump in question may be observed in the description given below in relation to the drawings attached which illustrate, by way of non-restrictive example, one way of constructing it.

Figure 1 shows an elevational view of the pump in question. On the left-hand side there is a view from the prefilter and on the right-hand side a view from the electric motor, and

Figure 2 shows a lengthwise cutaway view of the centrifugal pump.

[0010] We may see from these figures that the centrifugal water circulation pump in question consists of an electric pump 1 and a prefilter 2, with a pressure chamber 3 placed between them .

[0011] The electric pump 1 ist equipped with an electric motor 4 whose shaft 5 moves a multi-vane impeller 6 which turns inside a diffusion chamber 7, partly sealed by a diffuser 8.

[0012] The liquid enters coaxially to the impeller 6 and is dispatched by centrifugal force to a pressure chamber 9, placed between the electric motor 4 and the prefilter 2.

[0013] The prefilter 2 is so arranged that it comprises a vertical filter bowl 10 installed inside an outer bowl 11 tightly sealed by an outside threaded cover 12 and fitted with an external intake mouth 13 and an outlet pipe 14 connected to the axial inlet of the impeller 6.

[0014] The intake liquid is forced to pass through the walls of the above-mentioned filter bowl 10 before reaching the electric pump 1.

[0015] The pump body, forming an integral part with the prefilter 2, is linked to the housing of the electric motor 4 by a distinctly truncated cone-shaped connecting shield 15. The pressure chamber 3 and the electric pump 1 are hermetically separated by a distinctly biconic-shaped spacer 16.

[0016] The part 16 is provided with a centre hole and so arranged that its outer edge 17 is trapped. There is an 0-ring seal placed between the respective adjoining edges of the afore-mentioned connecting shield 15 and the pump body. The edges of the afore-mentioned centre hole hold a conventional mechanical ceramic seal 19 of the impeller 6.

[0017] The impeller shaft is provided with a hollow cylindrical extension 20 adapted for fitting on the shaft 5 of the electric motor. The length of the extension is such that its inner end is positioned between the mechanical seal 19 and the electric motor 4.

[0018] The inner edge 21 of the diffuser 8 engages in the linking edge 22 of the two cones of the biconic spacer 16.

[0019] On the wall of the inner cone of the spacer 16 there is at least one shoulder 23 for producing swirl in the water crown while the impeller 6 is working,in order to improve the cooling of the mechanical seal 19.

[0020] The electric motor 4 is linked to the pump body and to the prefilter 2 by only four through bolts 24.

[0021] Under the pump body there is a stand 25 for supporting the assembly, engaged by a dovetail coupling 26 at the bottom of this pump body and locked at one end by stops in the dovetail joint and at the other end by resting against the afore-mentioned cutt-off cone-chaped shield 15.

Claims

1. Centrifugal pump for water recirculation, particularly suitable for swimming pools, of the type comprising a centrifugal electropump (1), a prefilter (2) and a pressure chamber (3, 9) between them, the electropump (1) being equipped with an electric motor (4) whose shaft moves a multi-vane impeller (6) which turns inside a diffusion chamber (7), partly sealed by a diffuser (8), the prefilter (2) being arranged, so that it comprises a vertical filter bowl (10) installed inside an outer bowl(11) tightly sealed by an externally threaded cover (12) and fitted with an external intake mouth (13) and an outlet pipe (14) connected to the axial inlet of the impeller (6), characterized in that the pump body, forming an integral part with the prefilter (2), is linked to the housing of the electric motor (4) by a distinctly cut-off cone-shaped connecting shield (15), and the pressure chamber (3, 9) and the electric pump (1) are hermetically separated by a dinstinctly biconic-shaped spacer (16), provided with a centre hole and so arranged that its outer edge (17) is trapped, while an 0-ring seal (18) is placed between the respective adjoining edges of the connecting shield (15) and the pump body, whilst the edges of the centre hole hold a ceramic seal (19) of the impeller (6).

2. Centrifugal pump according to claim 1, characterized in that the impeller shaft is provided with a hollow cylindrical extension (20) for fitting on the electric motor shaft (15) and of a length such that its inner end is positioned between the mechanical seal (19) and the electric motor (4).

3. Centrifugal pump according to claim 1 or 2 , characterized in that the inner edge (21) of the diffuser (8) engages in the linking edge (22) of the two cones of the biconic spacer (16).

4. Centrifugal pump according to anyone of claims 1 to 3, characterized in that on the wall of the inner cone of the biconic spacer (16) there is at least one shoulder (23) for producing swirl in the water crown while the impeller (6) is working, in order to improve the cooling of the mechanical seal (19).

5. Centrifugal pump according to anyone of claims 1 to 4, characterized in that the electric motor (4) is linked to the pump body and the prefilter (2) by through bolts.

6. Centrifugal pump according to anyone of claims 1 to 5, characterized in that under the pump body there is an assembly support stand (25), engaged by means of a dovetail coupling (26) at the bottom of said pump body and locked at one end by stops in the dovetail coupling and at the other end by resting against the cut-off cone-shaped connecting shield

(15).

Drawing