Patent Description:
In a typical centrifugal pump; fluid is accelerated through centrifugal forces exerted on it by an impeller, which are used to transmit energy to the fluid being pumped. The pump may be controlled by a system automated using a capacitive sensing device. On the bottom of the pump, an impeller is located and protected against debris in the fluid by a strainer that will help to prevent some large particulates from getting stuck on the impeller and impede the rotation of the motor. The capacitive sensing device is integrated on a printed circuit board (PCB) that is programmed to control the function of the pumping unit. The sensor basically senses the presence of water and turns the pumping unit on to evacuate the water, e.g., on bilge and shower drain systems, once that water is down to a certain remnant level the PCB will automatic turn the pump off.

The assignee of the present application manufacturers and markets bilge pumps for the marine industry. Pumps used in this application are usually centrifugal type driven by a permanent magnet DC motor. These pumps feature an inlet and a discharge from which a hose connection is attached for routing of the discharge water out of the boat or vessel. Most of these pumps are controlled either manually by means of a panel mounted toggle switch or an automatic level switch. This level switch activates the pump motor when it senses the presence of water around the pump. Level switches usually are of the float type with dry contacts or an electronic sensor type. The switch can be a separate device or can be integral to the pump itself.

The environments in which the pumps operate usually contain debris in varying amounts. By way of example, the debris/contaminants may consist of oils, paper or cloth remnants from cleaning towels or other organic matter. These contaminants work to inhibit proper operation of the sensing device. Debris can sometimes adhere to the sensing surface, thereby causing false sensing signals where secondary failure modes can occur.

<CIT> describes a sensor system for sensing liquid level in a bilge.

<CIT> describes a sewage tank comprising ribs with for use with a pump.

<CIT> describes a quick flush valve for flushing or winterizing of cooling systems of inboard marine engines.

<CIT> discloses a submersible pump with an integrated capacitive level sensor.

<CIT> describes a sensor system for sensing liquid level in a bilge, for use in automatic bilge pump actuation.

<CIT> describes a submersible water pump, which includes a pump main body and a water level switch, the water level switch essentially consisting of at least two sensor units which are sufficiently exposed to water, as well as a control circuit unit which controls the activation and deactivation of the main pump body.

It is an object of the invention providing a pump designed to inhibit the adhesion of debris on the sensing surface. This object is achieved by a pump comprising the features of claim <NUM>. By way of example, the geometry may include a series of ribs placed to decrease adhesion surface area. The theory is that if debris will not stick, this will allow the sensor to function as designed.

In operation, the pumping unit according to the present invention improves the sensing effectiveness by changing the geometric design when compared to the known pumping units. Adding ribs at the sensing area will restrict towels and other objects from being in touch with the sensor area and prevent the pump from falsely sensing when no water is around to be pumped. In addition, these ribs in conjunction with a flat outside sensing surface improve the structural design for a better heat resistance, preventing the deformation when the unit is under thermal stress environment.

The present invention is as defined in claim <NUM>.

According to some embodiments, the pump may also include one or more of the following features:
The ribs may be arranged on the flat surface and dimensioned so that there is a space in-between adjacent ribs to receive the liquid between adjacent ribs when the object is stuck on, or in contact with, the ribs.

The ribs may be arranged on the outside sensing surface vertically or horizontally in relation to the pump axis.

The ribs may be symmetrically arranged on the outside sensing surface.

The ribs may include a shorter middle rib and longer outer ribs.

The ribs may be configured to provide heat resistance and structural rigidity to prevent deformation of the outside wall surface from thermal stress.

The liquid sensing device may be a capacitive sensing device, e.g., such as a printed circuit board having a capacitive sensing device.

The pump may be, or take the form of, one of the following:.

The liquid sensing device may include a high liquid level sensor configured to sense a high liquid level and turn the pump ON, and includes a low liquid level sensor configured to sense a low liquid level and turn the pump OFF.

In effect, the new geometric ribs configured on the liquid sensing areas help to prevent objects from being stuck on the sensing surface and as a consequence avoid the malfunction of the pumping unit. These new ribs form a physical perimeter around the sensor, e.g., that avoid or prevent other object different than a liquid density to be in touch with the sensor. By way of example, these ribs may be located on a planar surface perpendicular to bottom of the pump and right at the back side of the pump, e.g., at the opposite side of the water outlet.

The drawing includes <FIG>, which are not necessarily drawn to scale, as follows:.

In the drawing, every element is not labeled with every reference no. and lead line to reduce clutter in the drawing as a whole.

By way of example, and according to the present invention, <FIG> shows a pump generally indicated as <NUM> (<FIG>), <NUM> (<FIG>) featuring a new and unique combination of a liquid sensing device <NUM> and a pump body or housing <NUM>.

As shown in <FIG> and <FIG>, the pump body or housing <NUM> may be configured with some arrangement of back side pump ribs <NUM> that help the liquid sensing device <NUM> to prevent a malfunction of the pump <NUM> by avoiding face-to-face contact between an outside housing wall of the pump body or housing <NUM> and some debris in the liquid or fluid being pumped, e.g., such as a wet towel or other physical interference, that may foul the liquid sensing device <NUM> and cause it to send a signal for turning the pump <NUM> ON when there is no presence of water that needs to be pumped. For example, if a wet towel is stuck on or against the outside housing wall, and there is no fluid to be pumped, the liquid sensing device <NUM> may sense the liquid in the towel and send the signal for turning the pump <NUM> ON. (The pump may also stay ON, which can reduce the pump life, drain the battery of the boat or vessel, and cause other undesirable outcomes as well.

The liquid sensing device <NUM> may be configured, mounted or arranged in a back part generally indicated as <NUM> of the housing <NUM>.

As shown in <FIG>, and by way of example, in addition to the liquid sensing device <NUM> and the pump body or housing <NUM>, the major components of the pump <NUM> may also include a cap plug 10a, a cap 10b, a self tapping screws 10c, a thermal cutoff (TCO) 10d, a motor 10e, a motor mount 10f, a shaft seal <NUM>, a grommet <NUM>, wires 10i, an O-ring 10j, an impeller <NUM>, an inlet pump <NUM> and a strainer <NUM>.

The liquid sensing device <NUM> may be configured to sense the level of a liquid collecting outside the pump <NUM> and turn the pump <NUM> ON/OFF for pumping the liquid. As shown in <FIG> and <FIG>, and by way of example, the liquid sensing device <NUM> may take the form of a printed circuit board (PCB) and sensor. The PCB may be configured with a capacitive sensing device. Printed circuit boards having capacitive sensing devices are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the art. The scope of the invention is also not intended to be limited to any particular type or kind of liquid sensing device either now known or later developed in the art, and may include other types or kinds of liquid sensing devices other than printed circuit boards having capacitive sensing devices.

By way of example, consistent with that shown in <FIG>, the pump sensor <NUM> will determine the pump function ON/OFF by two predefined level sensor represented by bullets labeled A and B. For example, when the water level (bullet C) goes up to a sensor level <NUM> (bullet A), the sensor <NUM> will send a signal to the motor 10e and turn the pump <NUM> ON and make the impeller <NUM> rotate (bullet E), then water will be pulled by a centrifugal force of the impeller <NUM> from the inlet pump <NUM> (bullet <NUM>) to be carried up by a centrifugal motion via and through the pump body cavity (bullet <NUM>) and out the pump outlet (Bullet <NUM>), so as to evacuate all water from the bilge until the water level (Bullet <NUM>) goes down to the sensor level <NUM> (bullet <NUM>), and then the sensor <NUM> will send the signal to turn the pump <NUM> OFF to complete the cycle.

By way of example, the pump sensor <NUM> may include built-in programming that can sense when the pump <NUM> is running, but not pumping water to protect the pump, as well as the vessel and the vessel's batteries in which it is being used. By way of example, in some implementations if debris fouls the sensor <NUM> or the pump <NUM> becomes air-bound, then the PCB may be configured to stop the pump from running, e.g., and begin to check periodically for water entry (such as every <NUM>½ minutes). Once the debris is removed, the pump <NUM> may be configured to revert to normal operation, e.g., by turning ON when the water reaches approximately <NUM>½" (<NUM>) (Sensor Level <NUM> (<FIG>)) and by shutting OFF the water reaches approximately <NUM>/<NUM>" (<NUM>) (Sensor Level <NUM>).

The housing <NUM> includes a housing wall <NUM> configured to contain the liquid sensing device <NUM>. The housing wall <NUM> includes an outside wall surface 20a with an outside sensing surface 20b. The liquid sensing device <NUM> inside the housing <NUM> is mounted in relation to the outside sensing surface 20b. The outside sensing surface 20b includes the ribs <NUM> configured to extent or project outwardly away from the outside wall surface 20a, in order to prevent an object (e.g., having a density different than the liquid density) from being stuck on the outside sensing surface 20b, and allow the liquid sensing device <NUM> to sense the level of the liquid collecting outside the pump <NUM> and touching the outside sensing surface 20b, so as to reduce a malfunction of the pump <NUM> due to the object contacting the outside sensing surface 20b.

The outside sensing surface 20b is a flat surface, and the ribs <NUM> are arranged on and project from the flat surface. The ribs <NUM> may be arranged on the flat surface and dimensioned so that there is a space to receive the liquid between adjacent ribs when the object is stuck on, or in contact with, the ribs <NUM>.

The ribs <NUM> may be configured to provide heat resistance and structural rigidity to prevent deformation of the outside wall surface 20a from thermal stress.

In effect, the new geometric ribs <NUM> on the sensing areas help to prevent objects from being stuck on the sensing surface and as a consequence avoid the malfunction of the pumping unit. These new ribs form a physical perimeter around the sensor that avoid other object, e.g., including other objects different than a liquid density, to be in touch with the sensor surface 20b. By way of example, these ribs <NUM> are located on the planar surface perpendicular to bottom of the pump and right at the back side of the pump, e.g., at the opposite side of the water outlet, consistent with that shown in <FIG> of the drawing.

<FIG> show an embodiment of a pump <NUM> of the present invention, e.g., having five (<NUM>) ribs <NUM>.

In comparison, <FIG> show an embodiment of a pump <NUM> of the present invention, e.g., having seven (<NUM>) ribs <NUM>.

As shown, the ribs <NUM> are arranged on the outside sensing surface 20b vertically in relation to the pump axis A (<FIG>), as well as horizontally in relation to the pump axis; the ribs <NUM> may be symmetrically arranged on the outside sensing surface; or the ribs may include a shorter middle rib and longer outer ribs. Moreover, and by way of example, the ribs <NUM> may be configured with a contour and a dimension, e.g., consistent with that shown in the drawing.

However, the scope of the invention is not intended to be limited to the number of ribs <NUM>, the placement/configuration of the ribs <NUM>, the orientation (e.g., vertical or horizontal) of the ribs <NUM>, the dimension of the ribs <NUM>, etc.; and embodiments are envisioned, and the scope of the invention is intended to include, implementations having a different number of ribs, a different placement/configuration of the ribs, a different orientation (e.g., vertical or horizontal) of the ribs, a different dimension of the ribs, etc., than that shown and described herein.

Claim 1:
A pump (<NUM>) comprising:
a liquid sensing device (<NUM>) comprised in the pump and configured to sense the level of a liquid collecting outside the pump (<NUM>) and turn the pump (<NUM>) on/off for pumping the liquid; and
a housing (<NUM>) having a housing wall (<NUM> configured to contain the liquid sensing device (<NUM>), the housing wall (<NUM>) having an outside wall surface (20a) with an outside sensing surface (20b) , the liquid sensing device (<NUM>) being arranged or mounted inside the housing (<NUM>) in relation to the outsie sensing surface (20b), in order to allow the liquid sensing device (<NUM>) to sense the level of the liquid collecting outside the pump (<NUM>) and touching the outside sensing surface (20b),
characterised in that the
outside sensing surface (20b) has ribs (<NUM>) configured to extend or project outwardly away from the outside wall surface (20a) , in order to prevent an object from being stuck on the outside sensing surface (20b) , so as to reduce a malfunction of the pump (<NUM>) due to the object contacting the outside sensing surface (20b),
wherein the outside sensing surface (20b) is a flat surface, and the ribs (<NUM>) are arranged on and project from the flat surface.