Pump with a resilient seal.

(54) Title: PUMP WITH AN ELASTIC SEAL. (54) Title: PUMP WITH A RESILIENT SEAL.

(57) Summary

A pump comprising a housing (10, 210, 300, 410), the housing having an interior defining a rotor path (10, 210, 300, 410), an inlet (111,211) formed in the housing (10, 210 , 300, 410) in a first position on said rotor path, an outlet (12,212) formed in the housing (10, 210, 300, 410) in a second position on said rotor path separated from said first position. A rotor (15, 315, 350, 415) is rotatable in the housing. At least a first surface is formed on the rotor (15, 315, 350, 415) and sealed against said rotor path of the housing (10, 210, 300, 410). At least a second surface is formed on said rotor (15, 315, 350, 415) circumferentially separated from said first surface and forms a chamber with the rotor path passing around said rotor path to the rotation of the rotor (15, 315, 350, 415) to transport the fluid around the housing (10, 210, 300, 410) from the inlet (111,211) to the outlet (12, 212). An elastic seal (114, 214) is formed in one piece with the housing (10, 210, 300, 410), located on said rotor path and thus extends between the outlet (12,212) and the inlet (111,211) in the direction of rotation of said rotor (15, 315, 350, 415) with which the first rotor surface is sealed and elastically deformed, rotating the seal (114,214) as the rotor (15, 315, 350, 415) around the rotor path within the housing to prevent fluid from flowing from said outlet (12, 212) to said inlet (111,211) beyond the seal. A passageway (101, 201) may be provided to supply the fluid to a lower surface of the seal (114,214) at a pressure that acts to drive the seal (114, 214) against the rotor (15,315,350, 415). The rotor path may be frusto-conical with the first rotor surface (15, 315, 350, 415) also being frusto-conical and being in coupled engagement with the rotor path.

(57) Abstract

A pump comprises a housing (10, 210,300,410), the housing having an interior defining a rotor path (10,210, 300,410), an inlet (111,211) formed in the housing (10, 210, 300, 410) at a first position on said rotor path, an outlet (12, 212) formed in the housing (10, 210, 300, 410) at a second position on said rotor path spaced from said first position. A rotor (15, 315, 350, 415) is rotatable in the housing. At least one first surface is formed on the rotor (15, 315, 350, 415) and seáis against said rotor path of the housing (10, 210, 300, 410). At least one second surface is formed on said rotor (15, 315, 350, 415) circumferentially spaced from said first surface and forms a chamber with the rotor path that travels around said rotor path on rotation of the rotor (15, 315 350, 415) to convey fluid around the housing (10, 210, 300, 410) from the inlet (111, 211) to the outlet (12, 212). A resilient seal (114, 214) is formed in one piece with the housing (10, 210, 300, 410), located on said rotor path and so extends between the outlet (12, 212) and the inlet (111, 211) in the direction of rotation of said rotor (15, 315, 350, 415) that the first rotor surface seáis with, and resiliently deforms, the seal (114, 214), as the rotor (15, 315, 350, 415) rotates around the rotor path within the housing to prevent fluid flow from said outlet (12, 212) to said inlet (111,211) past the seal. A passage (101,201) may be provided to supply fluid to an under surface of the seal (114,214) at a pressure that acts to urge the seal (114, 214) against the rotor (15, 315, 350, 415). The rotor path may be frustoconical with the first surface of the rotor (15, 315, 350, 415) also being frustoconical and being a mating fit with the rotor path.

_YO LO SE_

MCRItMHA M SCOfMOMA

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Institute

Mexican Property

Industrial

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PATENT TITLE NO. 337264

Owner (s): QUANTEX PATENTS LIMITED

Address: 87 Rictiford Street, London W6 7HJ, UK

Denomination: PUMP WITH AN ELASTIC SEAL

Classification:

Inventor (s):

lnt.CI.8: F01C19 / 00; F01C5 / 04; F04C15 / 00; F04C5 / 00 RICHARD PAUL HAYES-PANKHURST; PETER WILLIAM ROSS

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industrial.

fulo lo h: Ificlal de

Mexican Institute of Industrial Property (DOF 12/27/1999, reformed &lt;delega I Signed the Organic

Say sound with the article cc Me from that of schoa.

Impa irribles, before the bis 2 of li. And of the 1/12/1997, / 05/1999,

2); articles 1 ·, 3 'ration V in subscribes the present Industrial Piflpiedad (Diario

2E 11/2004, 06/16/2005, 25ll / 2006, 0105 / 2009,08 / 01/2019? to a), 4 'and 12 · fraction I and III d Regulation of the In:

) 7/2002, 07/15/2004, 28 / // 2004 and&gt; 3/2007); Articles 1, 3, 4 * di and (DOF, 12/14/1999,

I and III and 30 of the Statute

2, 07/29/2004, 04/08/2004 and 09/13 / 2l&gt; 7); 1st, 3rd res of the

Regional Offices, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the Mexican Institute of Industrial Property. (DOF 12/15/1999, amended on 02/02/2000,29 / 07/2004, 04/08/2004 and 09/13/2007).

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Issue Date: February 19, 2016

DIVISIONAL DIRECTOR OF PATENTS

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NAHANNY CANAL REYES

&gt; Sand! No. 550, Floor 1,

Coi. Pueblo Santa María Tepepan Xochimiico, C P. 16020,

Mexico City

Tei. (55) 53 34 07 00 www.iiTtpi.gob.rnx

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MXZ2016 / 15117

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MXÍ

Ü WII 01109¾

PUMP WITH AN ELASTIC SEAL:

1.

MEXICAN PROPERTY ACT

INDUSTRIAL

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FIELD OF THE INVENTION The invention relates to pumps.

BACKGROUND

A known form of pump comprises a housing with an inlet for connection to a fluid source and an outlet for the pumped fluid with the inlet and outlet being separated around a path of a rotor within the housing. The rotor includes at least one surface that forms, with the housing, a closed chamber that passes around the housing to transport fluid around the housing. In this specification, the term fluid includes both gases and liquids.

Such a pump is described in WO 2006/027548 in which a seal is provided in the housing between the inlet and the outlet to seal against the rotor. A first problem with pumps of this type is that the housing and seal are formed separately and then fit together. As described in WO 2006/027548, the housing can be injection molded and the seal attached to the housing using an adhesive. Alternatively, the seal can be molded with the housing in a two pass injection molding process. This is a problem when there are two or more cameras because

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<img file="MX337264B_D0009.tif" />

Any unevenness in the joint between the housing and the seal can cause a leak between the adjacent chambers, particularly in higher pressure differences between the inlet pressure and the outlet pressure and when the vertices of the rotor are placed by pressing the seal. This leakage causes inaccuracy in the pump flow rate and can allow for unwanted back flow through the pump when stopping or at low flow rates.

SUMMARY

<td>According to a</td><td>first aspect</td><td>of</td><td>the invention,</td>

<td>a pump is provided</td><td>that includes</td><td>a</td><td>accommodation,</td>

<td>having accommodation</td><td>an interior</td><td>than</td><td>define a</td>

rotor path, an inlet formed in the housing in a first position on said rotor path, an outlet formed in the housing in a second position on said rotor path separated from said first position, a rotatable rotor in said housing, at least a first surface formed in the rotor and which is sealed against said rotor path of the housing, at least a second surface formed on said rotor circumferentially spaced from said first surface and forming a chamber with the rotor path passing around said rotor path to rotor rotation to transport fluid around the housing from inlet to outlet , an elastic seal formed in a *! J and H! i V

MFXICA INSTITUTE? Of faith

ÍNO'JITP.i.

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part with the housing, located in d.-i rha._ ¿a rotor and thus extending between the outlet and the inlet in the direction of rotation of said rotor with which the first rotor surface is sealed and elastically deformed, the seal as the rotor rotates around the rotor path within the housing to prevent fluid from flowing from said outlet to said inlet past the seal.

A further problem arises with such a pump if there is an inequality, firstly between the force required to form a seal between the rotor and the housing and, secondly, between the fluid pressure either at the inlet or at the outlet. At higher pressures, a higher sealing force is required but, if such a higher force is used at lower pressures, then frictional forces are unnecessarily increased and the torque required to drive the rotor is unnecessarily high. If a lower sealing force is used at high pressures, then there may be a leak between the seal and the rotor and higher outlet pressures cannot be achieved.

In accordance with a second aspect of the invention, a pump is provided comprising a housing, the housing having an interior defining a rotor path, an inlet formed in the housing in a first position on said rotor path, an outlet formed in the housing in a second position sesvtfSbflBflMb

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ΜΡΪ

- 4 - MEXICAN INSTITUTE

FROM THE INDUSTRIAL PRESSURE on said rotor path separated from said first position, a rotor rotatable in said housing, at least a first surface formed in the rotor and which is sealed against said rotor path of the housing, at least a second surface formed on said rotor circumferentially separated from said first surface and forming a chamber with the rotor passing around said rotor path to the rotation of the rotor to transport the fluid around the housing from the inlet to the outlet, an elastic seal located on said rotor path and thus extending between the outlet and inlet in the direction of rotation of said rotor with which the rotor surface is sealed and elastically deformed, the seal as the rotor rotates around the rotor path within the housing to prevent fluid from flowing from said outlet to said inlet beyond the seal, the seal having a lower surface opposite the surface of the seal in contact with the rotor, a passage being provided to supply said fluid to said lower surface at a pressure that acts to propel the seal against the rotor.

In WO2006 / 027548, the rotor is provided with

<td colspan="2">one or more cameras</td><td colspan="2">having</td><td>each camera</td><td>a</td><td>length</td>

<td>circumferential</td><td>than</td><td>is</td><td>plus</td><td>cut that</td><td>the</td><td>distance</td>

<td>circumferential</td><td>between</td><td>the</td><td>port</td><td>input and</td><td>the</td><td>port of</td>

This limits the volume of fluid that can leak.

3B3fc i

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pump up.

<td>Agree</td><td>with a</td><td colspan="2">third aspect</td><td>of</td><td>the invention,</td>

<td>a</td><td>bomb</td><td>than</td><td>understands</td><td>a</td><td>accommodation,</td>

<td colspan="2">having accommodation</td><td>a</td><td>inside</td><td>than</td><td>define a</td>

rotor path, an inlet formed in the housing in a first position on said rotor path, an outlet formed in the housing in a second position on said rotor path separated from said first position, a rotatable rotor in said housing, a first surface formed on the rotor and sealed against said rotor path of the housing, said first surface having a circumferential length longer than the circumferential length between the inlet and the outlet, a second unique surface formed on said rotor circumferentially separated from said first surface, having a circumferential length longer than the circumferential length between the inlet and the outlet and forming a chamber with the housing passing around said rotor path to the rotor rotation to transport fluid around the housing from the inlet to the outlet, an elastic seal located on said rotor path and thus extending between the outlet and the inlet in the direction of rotation of said rotor with which the first surface and the second single surface are sealed and elastically deformed, the seal as the rotor turn around

I Mexican institute V; OF THE INDUSTRIAL

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of the housing housing the outlet outlet towards said inlet of the rotor path within which fluid flows from said beyond the seal.

In pumps of this type, the rotor and housing chamber have a generally cylindrical configuration by adjusting and rotating the rotor cylinder within the cylindrical chamber. The tightness of the fit required between the parts is determined during manufacture and is difficult to adjust during installation or in use.

In accordance with a fourth aspect of the invention, there is provided a pump comprising a housing, a rotor path defined by the housing and within the housing, an inlet formed in the housing in a first position on said rotor path, an outlet formed in the housing in a second position on said rotor path separated from said first position, a rotatable rotor in said housing, at least a first surface formed in the rotor and which is sealed against said rotor path of the housing, at least a second surface formed on said rotor circumferentially separated from said first surface and forming a chamber with the rotor path passing around said rotor path to rotor rotation to transport fluid around the housing from inlet to outlet, an elastic seal located above

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INSTITUI

DE LA (TC INDI frusto-conical and frusto-conical and said rotor path and pYi-pndjéndngp agí - o.nt-.ra — The exit and entry in the direction of rotation of said rotor with which the rotor surface is sealed and elastically deforms, the seal as the rotor rotates around the rotor path within the housing to prevent fluid from flowing from said outlet to said inlet past the seal, the rotor path being the first rotor surface being in a fit coupled with the rotor path.

In this case, the relative positions of the rotor and housing can be adjusted axially.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a more detailed description of some embodiments of the invention, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic cross section through a pump known as described in WO 2006/027548 which includes a housing provided with an inlet and an outlet and a rotor rotatable within the housing and which is sealed against a seal provided by the housing, the rotor being shown in a first angular position,

Figure 2 is a view similar to Figure 1 but showing the rotor of the known pump rotated by ^{; ί}ί

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about 30 ° from position mosLTdiiar'éff'Ta ^ Tgura 1 ^

Figure 3 is a view similar to Figure 1 but showing the rotor of the known pump rotated by approximately 60 ° from the position shown in Figure 1,

Figure 4 is a schematic cross section through a pump according to the invention including a housing provided with an inlet and an outlet and a rotor rotatable within the housing and which is sealed against a seal formed in one piece with the housing .

Figure 5 is a view similar to Figure 4 but showing a modified form of the pump in which a port is provided leading from a point adjacent to the outlet to behind the seal,

Figure 6 is a view similar to Figures 1 to 3 and showing a pump according to the invention that includes a rotor provided with a single chamber,

Figure 7 is a longitudinal cross section through a pump of the general type shown in Figures 1 to 3 but with a rotor and housing having a frusto-conical configuration,

Figure 8 is a longitudinal cross section of a pump of the general type shown in Figure 7 but with a second frusto-conical rotor and housing configuration,

Figure 9 is a view similar to Figure 8 but

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showing the provision of a spring for penirtCÍT 'he axial adjustment of the position of the rotor in relation to the housing,

Figure 10 is a side elevation of a serrated end cap for use as a spring in the Figure 9 embodiment,

Figure 11 is a view similar to Figure 7, but showing the provision of a spring between the rotor and the housing at the larger diameter end of the rotor, and

Figure 12 is an end view of the rotor of Figure 11.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to Figures 1 to 3, the known pump of WO 2006/027548 is formed by means of a housing indicated generally at 10 which can be formed by molding plastics, for example, of polyethylene or polypropylene. Housing 10 is formed with an inlet 11 for connection to a fluid source and an outlet 12 for pumped fluid. The interior of the housing 10 is cylindrical. The portion of the interior of housing 10 between outlet 12 and inlet 11, again in a clockwise direction as seen in Figures 1 to 3, contains a seal 14 which will be described in greater detail. later.

The housing 10 contains a rotor 15. The rotor 15 can be formed of a metal such as stainless steel or • 1

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MEXICAN INSTITUTE DfeLA? X0? ¡"2AD

INDUSTRIAL

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as a plastic part molded by iH7 ^ üTÓñ''dé ^ 'precision formed from a resin such as acetal. As seen in the figures, the rotor 15 is generally of circular cross section and includes four equal length recessed surfaces 16a, 16b, 16c and 16d equiangularly separated around the rotor and interconnected by the vertices 17a, 17b, 17c and 17d formed by the uniform portions of the rotor 15. Accordingly, each vertex is rounded to a curvature that coincides with the curvature of the cylindrical surface 13 of the housing so that the rotor is in tight fit within the cylindrical surface 13 of the housing that forms a rotor path for the rotor. As a result, each recessed surface 16a, 16b, 16c, and 16d forms a respective chamber 18a, 18b, 18c, and 18d with the cylindrical surface 13 of the housing because each surface 16a, 16b, 16c, and 16d passes around that rotor path. 13. If the housing 10 is formed of an elastic plastic material that deforms under load, the rotor 15 can be arranged to slightly loosen the housing 10, thus ensuring a fluid tight seal around each surface 16a, 16b, 16c, 16d.

The rotor 15 rotates clockwise in Figures 1 to 3 by means of an actuator (not shown in the Figures).

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Seal 14 is formed by a block of elastomeric material that is ductile, flexible, and elastic, such as that marketed under the Hytrel brand. Seal 14 connects to housing 10 to prevent fluid from passing between seal 14 and housing 10. This may be through the use of an adhesive. Alternatively, the seal 14 could be molded with the housing 10 in a 2 pass injection molding process. In the latter case, the seal material 14 must be such that it is welded to the housing to prevent leakage. Seal 14 has a first axial flange 19 adjacent to inlet 11 and a second axial flange 20 adjacent to outlet 12. The seal 14 has a rotor clutch surface 21 that has a length between the first and second flanges 19, 20, which is generally equal to the length of each of the recessed surfaces 16a, 16b, 16c and 16d between the corners 17a , 17b, 17c, and 17d associated and configured to match the shape of each recessed surface 16a, 16b, 16c, and 16d. The axial reach of the seal 14 is at least equal to the axial reach of the recessed surfaces 16a, 16b, 16c and 16d. The seal 14 projects into the space defined by an imaginary cylinder described by the continuation of the cylindrical surface 13 between the entrance 11 and the exit 12. The seal 14 can be fixed between the first and second axial flanges 19, 20 so that it leans out in relation to the seal

<img file="MX337264B_D0020.tif" />

<td>14 towards</td><td>the</td><td>ej e del</td><td>rotor</td><td>15 where the surfaces</td>

<td>discount</td><td>16a,</td><td>16b, 16c</td><td>and 16d</td><td>they are concave.</td>

<td></td><td>The</td><td colspan="3">The natural elasticity of the material will tend to</td>

<td>to return</td><td>the</td><td>seal 14</td><td>to</td><td>undistorted arrangement</td>

after distortion by means of rotor 15, a spring (not shown) acting on the outer end of seal 14 can help this.

The operation of the known pump described above will now be described with reference to Figures 1 to 3. Inlet 11 is connected to a source of the fluid to be pumped, and outlet 12 is connected to a destination for the pumped fluid. Rotor 15 is rotated clockwise as seen in Figures 1 to 3. In the position shown in Figure

I, the rotor surface 16a elastically clings to the seal surface 21. In this way, the space between the housing 10 and the rotor 15 is closed in this area and the passage of fluid from the outlet 12 to the inlet is prevented.

II. In this position, vertex 17a is aligned with inlet 11 while rotor surfaces 16b, 16c, and 16d form respective sealed chambers 18b, 18c, 18d with cylindrical surface 13 of the housing. As a result of the first revolutions of the rotor 15, these chambers 18b, 18c, and 18d are filled with the fluid in the manner described below.

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Next, with reference to the —gigger ^ T -Q rotor rotation 15 by approximately 30 °, chamber 18d is now connected to outlet 12. Associated vertex 17d contacts seal surface 21 and is sealed against the surface. Accordingly, rotating rotor 15 forces fluid from chamber 18d into outlet 12. Furthermore, vertex 17a previously aligned with inlet 11, moves away from inlet 11 and allows rotor surface 16a to separate from sealed surface 21 to begin forming a chamber 18a (Figure 3) with cylindrical surface 13 of housing and with vertex 17d against seal surface 21.

Next, referring to Figure 3, further rotation of rotor 15 by approximately 60 ° from the position shown in Figure 1, results in the rotor surface 16d that previously formed chamber 18d adjacent to outlet 12, begin to contact seal surface 21 and seal against surface 21. Therefore chamber 18d is reduced in volume to zero and fluid from that chamber is forced through outlet 12. At the same time, the rotor surface 16a previously in contact with the seal surface 21 is now free of that surface 21 and forms a chamber 18a with the cylindrical surface 13 of the housing and chamber 18a receives fluid from the inlet 11. The vertex 17d between

<img file="MX337264B_D0022.tif" />

-14- ΙΜΡΙ €

ΙΝ £ Τ; :: λ · ·, t&gt; £ The industrial PS-.i.íU..OV surfaces 16a and 16d disengages from seal surface 21 and begins to align with input 11.

The rotor 15 is then moved to a position equivalent to the position shown in Figure 1 and the pumping continues. In this way, the fluid is pumped between inlet 11 and outlet 12.

It will be appreciated that the liquid flow rate is proportional to the rotation rate of the rotor 15 and to the

<td colspan="4">volumes of</td><td>chambers 18a, 18b, 18c</td><td>and</td><td>18d.</td><td>although the</td>

<td>rotor</td><td> 15</td><td>I know</td><td colspan="4">sample bearing four surfaces</td><td>16a, 16b,</td>

<td>16c,</td><td>16d,</td><td colspan="2">could</td><td>have any number</td><td>of</td><td colspan="2">surfaces such</td>

<td>how</td><td>a</td><td>or</td><td>two</td><td>or three surfaces</td><td>or</td><td>plus</td><td>of four</td>

surfaces. Surfaces 16a, 16b, 16c, 16d can be flat or can be, for example, curved convex or concave. These can be configured as slits formed by the intersection with the rotor 15 of an imaginary cylinder that has its axis at 90 ° towards the axis of the rotor and off-center towards one side of the axis of the rotor. As described above, the rotor clutch surface 21 of seal 14 can be configured to complement the shape of surfaces 16a, 16b, 16c, 16d.

At all times, the seal 14 acts to prevent the formation of a chamber between the outlet 12 and the inlet 11 in the direction of the rotor 15. The elasticity of the seal 14 allows it to always fill the space between the inlet 11

<img file="MX337264B_D0023.tif" />

and the outlet 12 and the portion of the rotor 15 "Sir" estcr '^-ie - As the pressure differential between inlet 11 and outlet 12 increases, there is an increase in the tendency of the fluid to pass between seal 14 and rotor 15. The use of a spring acting on seal 14 , as described above, will lessen that trend and thus allow the pump to operate at higher pressures. Therefore, the force applied by the spring determines the maximum pumping pressure. Pumps are known in which the outlet and inlet are separated by a thin vane that extends from the housing and makes contact with the rotor. In such pumps, there is a volume of fluid between the outlet and the inlet and a large pressure gradient across the vane that will increase as the rotor speed if the rotor drives the fluid through a fixed outlet and the viscosity of the fluid it leads to back pressure that rises with the flow rate. As a result, there is increased security of leakage through the pallet. In the pump described above with reference to the drawings, although there is a pressure differential between the inlet and the outlet, there is a smaller pressure gradient across the barrier between inlet 11 and outlet 12 as the fluid is gradually withdraws from chambers 18a, 18b, 18c and 18d towards outlet 12 and then, after further rotation of rotor 15, is gradually introduced into a

<img file="MX337264B_D0024.tif" />

chamber 18a, 18b, 18c and 18d on the side of the entrance. This reduces the possibility of leakage and allows the pump to provide accurately measured flow. Seal 14 acts as a displacer that displaces fluid between inlet 11 and outlet 12.

Everything described above with reference to Figures 1 to 3 is described in WO 2006/027548.

Next, with reference to Figure 4, the parts common to Figures 1 to 3 and Figure 4 will be given the same reference numbers and will not be described in detail.

In the embodiment of Figure 4, the separate seal 14 is omitted. A one-piece seal 114 is formed with the housing 10. These parts can be formed from a plastic material by a unique injection molding process. Seal 114 is a thin plastic wall that extends circumferentially from inlet 11 to outlet 12. The thickness of the wall may, for example, be 0.15 mm. The material of the housing 10 and the thickness of the wall are selected such that the wall can be distorted by contacting the vertices 17a, 17b, 17c, 17d of the rotor 15. Suitable materials may be polyethylene or polypropylene.

In order for the seal 114 to be flexible enough to follow the contour of the rotor 15 as it

<img file="MX337264B_D0025.tif" />

<img file="MX337264B_D0026.tif" />

MEXICAN INSTITUTE OF PROPERTY

INDUSTRIAL this turns seal 114 is required to be τηηΐ Haa ron nna very thin walled section. This requirement for a thin wall section over a large area is not normally found in typical injection molded parts. By carefully processing using high injection pressures, operating locally hot around the sealing area, and venting locally to eliminate gassing, 114 seals with a wall thickness between 0.1mm and 0.3mm can be achieved.

In a preferred process, the sliding portion of the tool that creates the outer surface of seal 114 is hydraulically controlled. The molten plastic is injected into the tool using the injection screw in the conventional manner where the wall thickness of the seal is approximately twice the design thickness thus allowing the molten material to flow easily through the seal. Instead of using the injection screw to provide the packing pressure as the mold cools and solidifies, the sliding portion of the tool advances hydraulically to create the desired seal wall thickness and at the same time create pressure packaging.

The use of a suitable flexible material for the seal 114 may require the molding of stiff members such as flanges in the housing 10 to provide it

<img file="MX337264B_D0027.tif" />

^ 'MEXICAN INDUSTRIAL TUTO

<img file="MX337264B_D0028.tif" />

sufficient rigidity. ---- In use, the presence of unitary formed seal 114 ensures that there are no leaks between chambers 18a, 18b, 18c, 18d, adjacent at the junction between housing 10 and seal 114 as a vertex 17a , 17b, 17c, 17d passes through the joint, as can occur in the known embodiment of Figures 1 to 3 particularly at higher pressures. The use of single discharge molding compared to double discharge or co-molding processes reduces the number of processes, has a faster cycle time, requires simpler molding tools and molding machinery and leads to performance of higher manufacturing and lower production costs. Compared to pumps of this type that omit these features, the pump in Figure 4 can have a longer operational life.

Next, with reference to Figure 5, the parts common to Figures 1 to 4 and Figure 5 will be given the same reference numbers and will not be described in detail.

In the embodiment of Figure 5, the seal 114 is formed in one piece with the housing 10, as in Figure 4. However, in this embodiment, an elastic displacement pad 141 is provided which rests against a underside of the seal 114 to boost seal

<img file="MX337264B_D0029.tif" />

against rotor 10.

This I allow.

<img file="MX337264B_D0030.tif" />

MEXICAN INSTITUTE OF PROPERTY

INDUSTRIAL use the pump higher pressures since the additional pressure of pad 141 resists the forced passage of fluid between rotor 10 and seal 114. The force applied by pad 141 is selected to allow the pump to operate at a lower end of a range of operating pressures for which the pump is designed, for example, up to 0.5 bar.

In addition, port 101 is provided at outlet 12 to allow communication between outlet 12 and the space behind seal 114. The effect of this is to allow fluid to flow through port 101 in operation and to apply fluid pressure to chamber 147 formed by the underside of seal 114, a turret 145 projecting upward from the rest of housing 10 and a cover 146 that closes turret 145. The force applied by the seal 114 to the rotor is therefore the sum of the force applied by the pad 141 and the force applied by the fluid. In this way, the applied force varies with the outlet pressure and the increase in the outlet pressure results in a corresponding increase in the force applied to the seal 114, thus preventing leaks between the seal 114 and the rotor 10 as a result of the increase. in pressure.

Pumps that have a

<img file="MX337264B_D0031.tif" />

MEXICAN INSTITUTE V- &lt;.. _t, FROM PRCf I'D / .O t '&gt; ·. ndustrí / '. l^ν-.9 · 1 bar maximum operating pressure without port 101 can be operated at pressures up to and exceeding 6 bar with port 101. Since the pressure applied to seal 114 automatically varies with outlet pressure, a single pump design incorporating such a 101 port for a variety of applications requiring a wide range of pressures. In addition, the pump always operates with the minimum torque requirement because the force between seal 114 and rotor 10 is never unnecessarily high.

Since pad 141 is held against the underside of seal 114, it is recommended to produce pad 141 elastic enough to transmit pressure from outlet 12 to seal 114.

Fluid could be supplied to the bottom surface from inlet 11 or from any other suitable point within housing 10 or supplied via a tube from a remote location in the fluid system, thus enabling the manufacture of a high pressure pump. inlet or outlet pressure.

Next with reference to Figure 6, the parts common to Figures 1 to 3 and Figure 6 will be given the same reference numbers and will not be described in detail. In Figure 6, housing 210 is molded in one piece as described above with reference to

<img file="MX337264B_D0032.tif" />

Figure 4. Housing 210 has an inlet 211 and an outlet 212 that are closely spaced in a circumferential direction. A seal 214 is formed in one piece with the rest of the housing 210 as previously described with reference to Figure 4 and is driven radially inward by an elastic pad 240 acting between the seal 214 and a base 241 formed in the housing. The space containing pad 240 is connected to outlet 212 by means of a port 201 formed between seal 214 and housing 210. This port 201 operates as previously described with reference to Figure 5.

The rotor 15 is provided with a single recessed surface 216 with the ends of this surface 216 interconnected by a single vertex 217 that extends axially along the rotor 15. The circumferential length of the vertex 217 is longer than the circumferential spacing of the entrance 211 and exit 212.

Seal 214 has a radially inwardly projecting clutch surface to rotor 221 driven by pad 240 in contact with the surface of recessed portion 216, as portion 216 passes over seal 214.

The pump of Figure 6 generally operates as previously described with reference to Figures 1 to 5. However, because the circumferential length of the .a. .Λ.

DEL DEL INSTITUTE

INDUSTRIAL greater than the recessed surface 216 is circumferential separation of the inlet 211 and the outlet ™ 212 the contact between these and the surface 216, as the surface 216 passes over the seal 214, prevents communication between the inlet and outlet ports 211 , 212.

The benefit of the pump of Figure 6 is that the single chamber 218 formed between the recessed surface 216 and chamber 13 maximizes the volume of fluid transferred from inlet 211 to outlet 212 at each rotation of rotor 15. This is further enhanced by the decrease in the circumferential spacing of inlet 211 and outlet 212, thus allowing to reduce the circumferential extent of vertex 217 and correspondingly increase the circumferential extent of recessed surface 216, thereby increasing the volume of chamber 218.

Of course, the pump in Figure 6 could have a separate seal, as described above with reference to Figures 1 through 4. In addition, port 201 is optional. Additionally, in the embodiments of both Figures 5 and 6, ports 101 and 201 are shown leading from outlet 12, 212 to the underside of seal 114, 214. Alternatively, ports may be driven from inlet 11, 211 associated with the underside of the seal 114, 214.

In the modalities described above with

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referring to Figures 1 to 6, the interior of the housing 10 and the exterior of the rotor 15 have complementary cylindrical surfaces. The operating torque and maximum pumping pressure are affected by the close fit between these parts, and small manufacturing variations can have an adverse effect by increasing the required torque and reducing the maximum pumping pressure by leaking.

Next, with reference to Figure 7, parts common to the pump of Figures 1 to 3 and the pump of Figure 7 will be given the same reference numbers and will not be described in detail.

In the pump of Figure 7, housing 300 has an interior having a first short cylindrical end 350 of smaller diameter and a second short end

351 of larger diameter interconnected by a frusto-conical section 352. Rotor 315 has a short cylindrical end 353 of smaller diameter with rotor body 354 being tapered so that rotor 315 fits, and can rotate inside housing 300 coinciding rotor body 354 with frusto-conical section 352 of housing 300. The smaller diameter end 353 of rotor 315 contains an annular seal 355 that seals between rotor 315 and housing 300. The seal may be an O-ring, a square seal, or a tongue seal and may

<img file="MX337264B_D0035.tif" />

molded either into housing 300 or rotor 315.

The included conical angle of the frusto-conical section 352 of the housing 300 and of the rotor body 354 can be between 2 ° and 20 ° and preferably can be between 5 ° and 15 ° more preferably 10 °.

The larger diameter end 350 of housing 300 contains a washer 357 which can be adjusted to move rotor 315 axially relative to housing 300 to adjust the fit between these parts and to obtain the required interface pressure between rotor 315 and housing 300 while minimizing the torque required to rotate rotor 315 through a drive plug 356 that extends axially toward the smaller diameter end 353 of rotor 350. This therefore mitigates the problem with manufacturing variations that affect the fit between the interior of a cylindrical housing and the coincidence of the rotor surface. The point of contact between washer 357 and rotor 315 can preferably be made close to the axis of rotor 315 to reduce the torque required to rotate rotor 315.

As seen in Figure 7, rotor 350 is provided with recessed surfaces, of which two are 16a, 16c, as seen in Figure 7. In addition, housing 300 is provided with a seal 14 that can ¿* ¡ tf - iiri-Trd. ·

<img file="MX337264B_D0036.tif" />

form in any of the shapes you parade with reference to the drawings. A pad 141 may be provided as described above with reference to FIG. 5 and held in place by a cap 358.

The pressure that drives the rotor 350 against the housing can be carefully controlled so that the interface pressure between the housing and the contact surfaces is adjusted to the desired value. This pressure can be provided in any of the following ways (which can be used individually or in any combination). Firstly, the pressure could be provided by means of a spring acting on the rotor 350. Second, pressure could be provided by modifying rotor 350 to create a rim or handle during manufacture so that it is held by the smaller diameter end of housing 300 in the proper position. Third, pressure could be provided by modifying the larger diameter end of housing 300 to hold rotor 350 in the proper axial position. Modification can be accomplished by heat treating the end of housing 300 and producing a tab around the circumference (heat staking) or by welding a washer to housing 300 to form an edge or molding a deformable tab in housing 300 on which it is closed in your site the

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rotor 315. _.....__

Next, with reference to Figure 8, in this embodiment, housing 401 contains a rotor 415 having housing 410 and rotor 415 mating frusto-conical surfaces, as previously described with reference to Figure 7. In this embodiment, the housing 410 is formed at one end of larger diameter with an L-section annular rim 450 having a cylindrical inner surface 451 coaxial with the axis of housing 410. At a smaller diameter end of rotor 410, an inwardly projecting center 452 is formed provided with a larger diameter outer cylindrical surface 453 connected to a smaller diameter outer cylindrical surface 454 by means of an angular annular gap 455.

Rotor 415 has a hollow cylindrical configuration and is received within housing 410. Rotor 415 is formed at its larger diameter end with a radially outwardly directed flange 456 containing an axially projecting annular seal 457 which abuts against inner surface 451 of annular flange 450 of housing 410 to form a seal between the parts. At the smaller diameter end of rotor 415, an inner surface 451 of rotor 415 is formed with an L-section annular seal 459 having a tongue 460 abutting against

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INSTITUTO MEXICANO VM LA TRO.'IFC'AÓ Γ industrial 'the outer cylindrical surface 453._ with the largest diameter of the center 452 to form a seal between the parts.

A groove is formed on the inner surface of flange 456 to transmit the drive to rotor 415. Alternatively, gear teeth may be formed on the outer surface of flange 456 to transmit the drive to the rotor.

A cap 461 has a chamfered end surface 462 and fits over the smaller diameter outer cylindrical surface 454 of the center 452 by holding the chamfered end surface 462 against the gap 455 and holding the open end 463 of the cap 461 against the seal of section L 459 on the smaller diameter end of rotor 415. Cap 461 is fixed to center 452, for example, by welding.

This clutch places rotor 415 axially relative to housing 410. It will be appreciated that as the dimensions and / or position of cover 461 vary, the axial position of rotor 415 relative to housing may also vary to provide interface pressure. required between rotor 415 and housing 410.

The pump of Figure 8 has an inlet and outlet (not shown) and a seal (not shown) and operates in another manner as described above with reference to Figures 1 to 7.

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MEXICAN INSTITUTE Di LA PROPIF.U / .D

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.e a metal such as stainless steel or a resin such as UüHRJ'ctCé'CSTí the rotor 15 could be produced, for example, from polyethylene or polypropylene.

The seal 14 need not have a configuration that matches the configuration of each recessed surface 16a, 16b, 16c, and 16d. The seal 14, for example, can have a natural configuration ie a continuation of the cylindrical surface of the housing 10 with an elastic spring or pad acting to distort the seal 14 towards the axis of the rotor 15. In practice the seal is formed at the same radius of curvature as the diameter of the cylindrical housing, but generally can be molded into curved configurations that cross the cylindrical volume as long as the joint between the housing and the seal is tangential to the cylinder defined by the inside the accommodation.

Rotor 15 can also be driven in a counterclockwise direction and the flow direction will be reversed. When ports 11 and 12 are placed symmetrically with respect to seal 14, the pump will provide the same flow characteristic in both directions. In practice it is found that higher outlet pressures can be obtained by moving the outlet port circumferentially slightly away from the seal 14 and this

<img file="MX337264B_D0039.tif" />

<img file="MX337264B_D0040.tif" />

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_ 9 Q _ MFXiCANO INSTITUTE

DE LA ÍROFIr-DAD INDUSTRIAL reduces the tendency of the fluid to recede between seal 14 and rotor 15 when vertices 17a, 17b, 17c, 17d are near the outlet port. In this case the flow rate in the counterclockwise direction is less because the seal 14 is not as effective in displacing the fluid from the chamber.

Next, with reference to Figure 9, the parts common to Figure 8 and Figure 9 will be given the same reference numbers and will not be described in detail.

In the pump of Figure 8, the position of the cap 461 determines the interface pressure between rotor 415 and housing 410. As described with reference to Figure 8, this force can be adjusted by varying the position and / or dimensions. of the cover 461.

This adjustment may be required to allow the pump to be used with fluids of different viscosities or with adverse rheological properties such as thickening at cut. For lower viscosity fluids, for example, a smaller gap is possible between rotor 415 and housing 410 without unduly increasing the torque required to rotate rotor 415. With higher viscosity fluids such as paint or edible sauces, it is advantageous to increase this space in the support area to reduce the torque required to rotate rotor 415. Such increased space does not lead to leakage of

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fluid does not affect outlet pressure or flow rate but such a larger gap can affect the self-priming capacity of the pump (when the pump and its supply lines are empty of fluid at the start of operation ).

The embodiment of Figure 9 addresses this problem by providing a spring 470 located around center 452 and acting between cap 461 and an annular wall 472 that extends radially from seal 459. The effect of spring 470 is to drive rotor 415 against the housing 410 and thus close the space between these parts when the pump is empty of fluid. This allows the gas to be pumped through the pump when the pump is set up thereby allowing higher viscosity fluids to be drawn into the pump to prepare the system. When such a higher viscosity fluid reaches the pump outlet, the increased outlet pressure and the thin film of liquid that forms between the mating surfaces between the rotor and housing act on rotor 415 to propel it away from housing 410 by compressing the spring 470, thereby increasing the space between rotor 415 and housing 410. Therefore the axial position of the rotor 415 in relation to the housing 410 is adjusted according to the pressure of the pumped fluid to increase the separation between the rotor

415 and housing 410 with a fluid pressure

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY increased at the pump.

<td></td><td>The</td><td>separation</td><td>between</td><td>the cap</td><td>461 and</td><td>the</td><td>stamp 459</td>

<td>limits</td><td>the</td><td>movement</td><td>maximum</td><td colspan="3">rotor 415</td><td>far from</td>

<td colspan="2">accommodation</td><td>410 and this</td><td>can</td><td>vary</td><td>according</td><td>I know</td><td>require.</td>

<td>Further,</td><td>the</td><td>constant</td><td>of</td><td>spring</td><td>can</td><td colspan="2">vary for</td>

provide different compression rates of the 470 spring under the action of a pumped fluid.

It is not necessary to provide this spring force by means of a coil spring 470 as shown in Figure 9. Any suitable form of spring such as a metal spring or plastic washer can be used. A possible variation is shown in Figure 10. As seen in this Figure, cover 461 is formed of a flexible material and is provided with a serrated open end so that each serrated edge 473 can flex when compressed. Open serrated end of cap 461 is pressed against seal wall 472 of seal 459 so that as rotor pressure 415 increases as a higher viscosity fluid is pumped through the pump, the serrated edges 473 flex to allow increased clearance between rotor 415 and housing 410.

Figures 11 and 12 show a second variation. In these figures, the pump is constructed as described above with reference to Figure 7 and given

<img file="MX337264B_D0044.tif" />

- 32 to the parts common to that figure and toTás Fi§U5? AS TI ^rand 12 the same reference numbers and are not described in detail.

Referring to Figures 11 and 12, the larger diameter end of rotor 350 is formed with two spring-loaded arms 370, 371 arched overhangs that extend far and around the larger diameter end. As seen in Figure 11, the free ends of the spring arms 370, 371 are held against the washer 357 and provide a spring force that drives the rotor 350 against the housing 300 and acts in the manner described above to allow pump setup with rotor 350 near housing 300 followed by increased separation as a higher viscosity liquid reaches the outlet.

Spring arms 370, 371 can be formed separately from rotor 350. When rotor 350 is molded, for example, spring arms 370, 371 can be co-molded with rotor 350. A preferred material for such molding is a polyacetal. because it has a low drag property. The benefit of a low drag spring is that it allows a range of viscosities to be pumped with a pump installation.

Of course, spring arms 370, 371 can be replaced by any other suitable form of spring acting between rotor 350 and housing 300, such as a

<img file="MX337264B_D0045.tif" />

coil spring or spring washer.

In this embodiment, the range of motion is again limited by the gap between the larger diameter end of rotor 350 and washer 357, and washer 357 can be adjusted or limited as desired.

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