Patent Description:
A hydraulic pump is a mechanical source of power that converts mechanical power into flow pressure. The hydraulic pump can be driven by an electrical drive motor. A flow is generated with sufficient power to overcome pressure induced by the load at the hydraulic pump outlet. In operation, the hydraulic pump creates a vacuum at the inlet thereby forcing liquid from the reservoir into the inlet line by mechanical action and delivers the liquid to the outlet and into the hydraulic system.

Centrifugal pumps are used for a wide variety of liquid pumping applications. Centrifugal pumps, generally, have a impeller to pump liquid by centrifugal force. Centrifugal pumps may be constructed in single stage or multi-stage configurations. Each stage includes a stationary diffuser and a mating, rotating impeller driven by a pump shaft connected to a drive motor. The stages are arranged in "series" to provide an enhanced overall pressure capability.

Wear rings may be used to absorb thrust, help prevent wear and/or provide a seal-like construction between different parts of the pump. Conventional wearing rings may be formed of metal, ceramic, plastic or carbon materials. The wear rings become consumed during operation and replacement of worn wear rings is required for normal operations.

In a centrifugal pump, a wear ring may be disposed between the impeller and a diffuser. The wear ring may be contained in a substrate that is coupled to the main body of the diffuser or the pump housing. Generally, a wear ring may be contained in a support structure that is nested or welded to a support surface on the pump housing or the body of the diffuser. Accordingly, in order to replace a worn wear ring, the support structure is first detached from the support surf ace and the wear ring therein replaced subsequently.

Examples of state-of-the art sealing arrangements for centrifugal pumps are available as follows.

Document <CIT> discloses a hydraulic sealing ring on the inlet of the impeller, particularly for single-stage and multistage pumps that is made in a rubber-like material. The ring has substantially radial openings which connect a shimming face to the outer one to allow a slight injection of liquid bled from the higher-pressure chamber in output from the impeller blades in the shimming region and to allow the creation and the maintenance of an extremely thin layer of liquid adapted to ensure a lubrication of the scraping surfaces with a reduced leakage towards the lowerpressure region at the input of the impeller. This is to counterbalance the radial force which tends to press the ring around the inlet of the impeller.

<CIT> discloses a centrifugal pump, in particular a fire pump, that comprises at least one impeller as well as sealing rings for sealing radial sealing gaps between the impeller and the pump casing. The sealing rings consist of a plastics material and are mounted in the casing with a snap connection.

Document <CIT> relates to a sealing ring unit for radially sealing the suction mouth of a pump impeller, in particular for a multistage pump. The unit comprises a sealing ring and a supporting member removably carrying the sealing ring. The supporting member has an annular inner portion defining an opening for receiving the suction mouth of the impeller. The sealing ring is mountable on the supporting member by means of a bayonet fitting to allow easy change of the sealing ring.

The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art system.

The present disclosure describes a pump as initially described, wherein the plurality of clutch members of the wear ring engages the opposite ends of the inlet with slack to provide for minimal relative movement.

The foregoing and other features and advantages of the present disclosure will be more fully understood from the following description of various embodiments, when read together with the accompanying drawings, in which:.

This disclosure generally relates to a pump having a wear ring removably coupled to a diffuser. <FIG> illustrates a pump <NUM>. <FIG> illustrates an enlarged view of a portion of the pump <NUM>. The pump <NUM> comprises at least one impeller <NUM>, at least one diffuser <NUM> and at least one wear ring <NUM>.

<FIG> and <FIG> illustrate a section through the pump <NUM>. With reference to <FIG> and <FIG>, The wear ring <NUM> is disposed between the impeller <NUM> and the diffuser <NUM>. Wear ring <NUM> is disposed at the inlet <NUM> of the diffuser <NUM>. Wear ring <NUM> is disposed at the neck <NUM> of the inlet <NUM>. Wear ring <NUM> is positioned adjacent the eye <NUM> of the impeller <NUM>. Wear ring <NUM> is removably coupled to the diffuser <NUM>. Wear ring <NUM> is removably coupled to the inlet <NUM> of the diffuser <NUM>. Wear ring <NUM> is removably coupled to the inner surface of the inlet <NUM>. The impeller <NUM> may be in contact with the wear ring <NUM> during operation of the pump <NUM>. The outer surface of the eye <NUM> of the impeller <NUM> may be in slidable contact with the wear ring <NUM> during operation.

Wear ring <NUM> is made of a deformable material. Wear ring <NUM> is configured to undergo a deformation during mounting to the diffuser <NUM> and removal from therefrom. In an embodiment, wear ring <NUM> is made of a plastic material.

The wear ring <NUM> has a plurality of radially extending clutch members <NUM>. The clutch members <NUM> are configured to hold a portion of the at least one diffuser <NUM>. Clutch members <NUM> are configured to hold a portion of the inlet <NUM> of the diffuser <NUM>. Clutch members <NUM> are configured to engage at the inner surface of the neck <NUM> of the inlet <NUM>. Clutch members <NUM> are configured to engage opposite ends of the inlet <NUM>.

<FIG> illustrates the wear ring <NUM> and <FIG> illustrates a section through the wear ring <NUM>. With reference to <FIG> and <FIG>, the wear ring <NUM> is substantially annular. Wear ring <NUM> has an outer surface <NUM> and an inner surface <NUM>. The outer surface <NUM> may contact the diffuser <NUM>. Inner surface <NUM> may contacts the impeller <NUM>. Clutch members <NUM> extend radially away from the outer surface <NUM>. Wear ring <NUM> has a first side <NUM> and an opposite second side <NUM>. First and second side <NUM>, <NUM> extend between the outer surface <NUM> and the inner surface <NUM>.

Each clutch member <NUM> comprises a first and a second tab portions <NUM>, <NUM>. The first and second tab portions <NUM>, <NUM> are spaced apart. First and second tab portions <NUM>, <NUM> are spaced apart on the outer surface <NUM>. First and second tab portions <NUM>, <NUM> are disposed on opposite edges of the outer surface <NUM>. Second tab portions <NUM> extends further from the outer surface <NUM> than the first tab portions <NUM>. First and second tab portions <NUM>, <NUM> are configured so as to engage opposite ends of the inlet <NUM> of the diffuser <NUM>.

With reference to <FIG>, the first and second tab portions <NUM>, <NUM> may be vertical relative to the outer surface <NUM>. The first and second tab portions <NUM>, <NUM> may be substantially perpendicular relative to the outer surface <NUM>. Each clutch member <NUM> may have a substantially U-shaped cross-section formed by the first and second tab portions <NUM>, <NUM> bordering the outer surface <NUM>.

With reference to <FIG> and <FIG>, the first tab portion <NUM> is an extension of a tab <NUM>. The tab <NUM> is provided on the first side <NUM> of the wear ring <NUM>. Tab <NUM> may be formed as a raised platform on the first side <NUM>. Tab <NUM> raises substantially vertically from the first side <NUM>. Tab <NUM> extends across the first side <NUM>. Tab <NUM> has a longitudinal axis D that extends across the first side <NUM>.

Tab <NUM> has an inner end <NUM> opposite to the first tab portion <NUM>. Inner end <NUM> does not extend over the inner surface <NUM>. Inner end <NUM> is in line with the inner surface <NUM>. Tab <NUM> extends over the inner surface <NUM> through the first tab portion <NUM>. First tab portion <NUM> has a free tab end <NUM> that is curved across a direction transverse to the longitudinal axis D of the tab <NUM>. Curved free tab end <NUM> reduces resistance against the inner surface of the inlet <NUM> of the diffuser <NUM> during mounting and removal of the wear ring <NUM>.

Tab <NUM> has tab sides <NUM>. The tab sides <NUM> may be perpendicular to the first side <NUM>. Tab sides <NUM> diverge from the inner end <NUM> to the first tab portion <NUM>. Tab sides <NUM> diverge from the inner surface <NUM> to the outer surface <NUM> of the wear ring <NUM>. The tab sides <NUM> have an angle α that is configured as required. In an embodiment, the tab sides <NUM> have an angle α of <NUM> degrees.

The wear ring <NUM> may comprise a number of tabs <NUM> as required. In an embodiment, the wear ring <NUM> may comprises at least two tabs <NUM>. The longitudinal axes D of the two tabs <NUM> extend radially relative to the wear ring <NUM>. Tabs <NUM> are mutually angularly spaced on the first side <NUM>. The tabs <NUM> are mutually angularly spaced at an angle β that is configured as required. The tabs <NUM> are mutually angularly spaced at an angle β of <NUM> degrees.

In a further embodiment, the wear ring <NUM> may comprise three tabs <NUM>. The longitudinal axes D of the three tabs <NUM> extend radially relative to the wear ring <NUM>. Tabs <NUM> are mutually angularly spaced on the first side <NUM>. The tabs <NUM> are mutually angularly spaced at an angle β that is configured as required. The tabs <NUM> are mutually angularly spaced at an angle β of <NUM> degrees.

The second tab portion <NUM> is portion of a lip <NUM>. Lip <NUM> extends laterally from the outer surface <NUM> of the at least one wear ring <NUM>. The lip <NUM> extends around the wear ring <NUM>. Lip <NUM> is configured as a continuous ring around the outer surface <NUM>. Lip <NUM> has a free lip end <NUM> that is curved across a direction transverse to the extension of the lip <NUM>. Curved free lip end <NUM> reduces resistance against the inner surface of the inlet <NUM> of the diffuser <NUM> during mounting and removal of the wear ring <NUM>.

In an embodiment, the second tab portion <NUM> is a discrete structure extending from the outer surface <NUM>. Second tab portion <NUM> extends laterally from the outer surface <NUM> of the at least one wear ring <NUM>. Second tab portion <NUM> has an end joined to the outer surface and a free lip end <NUM>. Free lip end <NUM> is curved across a direction transverse to the longitudinal axis of the second tab portion <NUM>. Curved free lip end <NUM> reduces resistance inner surface of the inlet <NUM> of the diffuser <NUM> during mounting and removal of the wear ring <NUM>.

The wear ring <NUM> may comprise the same number of second tab portions <NUM> as tabs <NUM>. The longitudinal axes of the second tab portions <NUM> extend radially relative to the wear ring <NUM>. Second tab portions <NUM> are mutually angularly spaced on the first side <NUM>.

With reference to <FIG>, in an embodiment, the wear ring <NUM> may have a cut-out <NUM>. The cut-out <NUM> may be annular. Cut-out <NUM> may be positioned between outer surface <NUM> and an inner surface <NUM>. Cut-out <NUM> may have an opening on the second side <NUM>. Cut-out <NUM> may reduce the weight of the wear ring <NUM>.

Wear ring <NUM> may have an inclined surface <NUM> extending between the second side <NUM> and the inner surface <NUM>. Inclined surface <NUM> may be annular. Inclined surface <NUM> may be concentric with the inner surface <NUM>. Inclined surface <NUM> may prevent the wear ring <NUM> from adhering to the eye <NUM> of the impeller <NUM>.

With reference to <FIG>, the wear ring <NUM> is mounted to the diffuser <NUM> and the clutch member <NUM> is coupled to the inlet <NUM> of the diffuser <NUM>. Wear ring <NUM> is retained in the mounted position by the plurality of clutch members <NUM> engaging opposite ends of the inlet <NUM>. In an embodiment, the wear ring <NUM> is floatingly mounted to the inlet <NUM>. The plurality of clutch members <NUM> may loosely hold the inlet <NUM>. The plurality of clutch members <NUM> engage opposite ends of the inlet <NUM> with slack to provide for minimal relative movement. The wear ring <NUM> be capable of angular movement relative to the inlet <NUM>. The first tab portion <NUM> engages a shoulder <NUM> joined to the neck <NUM>. Shoulder <NUM> defines the aperture of the inlet <NUM> into the diffuser <NUM>. The plurality of first tab portions <NUM> is mutually angularly spaced on the shoulder <NUM> around the aperture of the inlet <NUM>.

The second tab portion <NUM> engages a rim <NUM> of the inlet <NUM>. Rim <NUM> defines the aperture of the inlet <NUM> to the exterior of the diffuser <NUM>. In an embodiment, the lip <NUM> engages the rim <NUM>. Clutch member <NUM> is coupled over the inlet <NUM> such that the outer surface <NUM> of the wear ring <NUM> may contacts the inner surface of the neck <NUM>.

The first tab portion <NUM> extends from the tab <NUM>. The tab <NUM> extends axially from the wear ring <NUM>. The tab <NUM> extends axially from the wear ring <NUM> beyond the shoulder <NUM>. At least one tab <NUM> is configured to abut a vane <NUM> of the diffuser <NUM>. The at least one tab <NUM> abuts a vane <NUM> when the wear ring <NUM> undergoes a rotational movement on the inlet <NUM>. The abutting engagement of the tab <NUM> and the vane <NUM> serves as an anti-rotation mechanism of the mounted wear ring <NUM>.

In an embodiment, a terminal diffuser <NUM> does not have a vane <NUM>. The tab <NUM> may be configured to abut a body (not shown) extending from the diffuser <NUM>. The body may be soldered to the terminal end of the diffuser <NUM> and extends from the diffuser.

<FIG> illustrates the cross-section of a portion of the mounted wear ring <NUM> not having the clutch member <NUM>. The outer surface <NUM> of the wear ring <NUM> is held against the inner surface of the inlet <NUM>. In an embodiment, the lip <NUM> engages the rim <NUM>. The side <NUM> of the tab <NUM> is available to abut the vane <NUM> of the diffuser <NUM>.

In an embodiment, the pump <NUM> is a multi-stage pump comprising a plurality of impellers <NUM>; a plurality of diffusers <NUM> and a plurality of wear rings <NUM>.

The skilled person would appreciate that foregoing embodiments may be modified or combined to obtain the pump <NUM> of the present disclosure.

This disclosure describes a pump <NUM> having the wear ring <NUM> that is coupled to the diffuser <NUM>. The wear ring <NUM> is removably coupled to the diffuser <NUM>. A worn wear ring <NUM> is removed with efficiency and ease. The clutch members <NUM> enables the efficient removal and mounting of the wear ring <NUM>. Further, in a multistage pump <NUM> having a plurality of impellers <NUM> and diffusers <NUM>, the removably coupled wear rings <NUM> results in cost savings.

Claim 1:
A pump (<NUM>) comprising:
at least one impeller (<NUM>);
at least one diffuser (<NUM>) having an inlet (<NUM>); and
at least one ring (<NUM>) positioned between the at least one impeller (<NUM>) and the at least one diffuser (<NUM>) and removably coupled to the diffuser (<NUM>), the at least one wear ring (<NUM>) having a plurality of radially extending clutch members (<NUM>) wherein the clutch members (<NUM>) are configured to hold a portion of the at least one diffuser (<NUM>),
wherein said ring is a wear ring (<NUM>) having said plurality of clutch members (<NUM>) engaging opposite ends of the inlet (<NUM>), said wear ring (<NUM>) being capable of angular movement relative to the inlet (<NUM>), characterized in that said plurality of clutch members (<NUM>) engage the opposite ends of the inlet (<NUM>) with slack to provide for minimal relative movement.