Patent Description:
Air-operated diaphragm pumps are used for liquid transfer in many different industries. For instance, air-operated diaphragm pumps are used for liquid transfer where purity of the transfer liquid, high flow rates, and/or reliable and predictable flow volumes are needed. Air-operated diaphragm pumps are also used to transfer hazardous chemicals. For example, air-operated diaphragm pumps are commonly used in industries such as the food and beverage industry, chemical processing, oil and gas, and the semiconductor industry.

Diaphragm ruptures or leaks diminish the performance of the pump, and may introduce impurities into the transfer liquid, or may expose personnel to a hazardous transfer liquid. Leak detection devices can be used to detect diaphragm leaks. However, existing leak detection devices often rely on restrictive airflow paths to remove entrained liquid from pump exhaust air and detect a leak. Such restrictive airflow paths can reduce the operating efficiency and effectiveness of an air-operated pump by, for example, creating a backpressure on the pump's exhaust. The back pressure reduces the differential pressure available across a pump's diaphragm thus reducing the pump's output pressure and/or pumping rate. Accordingly, improvements are continually sought for diaphragm leak detection.

<CIT> belongs to the technical field of liquid material conveying security control in a chemical industry, and provides a security controller for diaphragm leakage liquid of an air diaphragm pump. The security controller comprises a rotary gas-liquid separator, a mandril, a gas source control valve, a gas discharge pipe, an overflow preventing device and a liquid seal device. <CIT> further provides a method for controlling the diaphragm leakage liquid of the air diaphragm pump through the security controller for the diaphragm liquid leakage of the air diaphragm pump. With the adoption of a mechanical ball float type pumping stop control method, air mixed with leaked liquid materials caused by a damaged diaphragm in the diaphragm pump is collected to a rotary air cylinder body, gas and liquid are separated by using a method of specific gravity, and a technology of pushing a float ball to close air source in the air diaphragm pump through aggregated leaked liquid is utilized. The security controller for the diaphragm leakage liquid of the air diaphragm pump can effectively overcome the maximum hazard which is likely to cause safety accidents by the fact that controlling methods of the traditional electric appliances are utilized in flammable and combustible environments in the chemical industry.

Implementations of the present disclosure are generally directed to a leak detection device. More specifically, implementations are directed to a diaphragm leak detection device for air-operated pumps and a pump system incorporating the leak detection device. Implementations of the leak detection device described herein employ a minimally restrictive path from the air exhaust of the air-operated pump, through the leak detection device, and into a pump muffler. Implementations of the leak detection device provide an air impingement surface directly in the flow path of the exhaust air from the pump. The air impingement surface causes heavy liquid particles entrained in the air (e.g., from a diaphragm leak) to fall out of the air flow when they impact the surface and it diverts the air around the surface. The liquid is collected in a liquid reservoir and a liquid level detector is used to alert personnel to the diaphragm leak.

A diaphragm pump leak detection device and a diaphragm pump leak detection method according to the present invention are set out in the independent claims. Further advantageous developments of the present invention are set out in the dependent claims.

According to the present disclosure, a surface of the liquid separator forms a direct impingement surface and the body of the diaphragm leak detection device is configured to direct airflow from the exhaust outlet against the direct impingement surface.

According to the present disclosure, the body of the diaphragm leak detection device includes an upper housing and a lower housing. The upper housing includes the airflow inlet and the airflow outlet. The lower housing defines the liquid reservoir.

According to the present invention, the liquid separator includes a cylinder and a sleeve. The cylinder is coupled to the body and positioned directly between the airflow inlet and the airflow outlet. The sleeve is configured to interface with a lower portion of the cylinder. The sleeve includes the channel, where a first end of the channel terminates at the lower portion of the cylinder and a second end of the channel opens to the liquid reservoir.

According to the present disclosure, the liquid level detector is coupled to the lower portion of the cylinder and extends into the channel.

According to the present disclosure, the body of the diaphragm leak detection device includes a shelf positioned above the liquid reservoir. The sleeve includes a tapered flange in contact with the shelf. The tapered flange separates the liquid reservoir from an airflow path in an upper portion of the body.

According to the present disclosure, the shelf includes at least one drain channel that provides liquid communication between the liquid reservoir and the airflow path.

According to the present disclosure, the liquid level detector comprises a float switch assembly.

According to the present disclosure, the body of the diaphragm leak detection device includes an upper housing and a lower housing. The upper housing includes the airflow inlet and the airflow outlet. The lower housing is separable from the upper housing. The lower housing includes the liquid reservoir, the shelf, and at least one drain channel.

The concepts described herein may provide several advantages. For example, implementations of the invention provide an air-operated pump leak detection device that imposes minimal flow restriction exhaust air. Implementations may provide leak detection capabilities with little or no increase in backpressure on air-operated pump exhaust.

<FIG> depicts a perspective view of an air-operated diaphragm pumping system <NUM>. The system includes diaphragm pump <NUM>, the pump's air-valve assembly <NUM>, a muffler plate <NUM>, a leak detection device <NUM>, and a muffler <NUM>. <FIG> depicts a functional diagram of an exemplary air-operated diaphragm pump <NUM>. In general, pump <NUM> operates by alternately applying high pressure air to one of two diaphragms 202A and 202B during a liquid discharge stroke and exhausting the air to atmosphere during a liquid suction stroke. In more detail, air valves in the air-valve assembly <NUM> direct pressurized air to the back side of diaphragm 202A. The diaphragms 202A and 202B act as separation membranes between the compressed air and the liquid. The compressed air moves diaphragm 202A away from the center of the pump <NUM>. Diaphragm 202B is pulled in by the shaft connected between the diaphragms 202A and 202B. As diaphragm 202B is on its suction stroke; air behind the diaphragm 202B is forced out to atmosphere through the exhaust outlet of the pump <NUM> (e.g., through the muffler plate <NUM>). The movement of diaphragm 202B toward the center of the pump <NUM> creates a vacuum within chamber 204B. Atmospheric pressure forces liquid through the inlet manifold and into chamber 204B.

When the pressurized diaphragm, e.g., diaphragm 202A, reaches the limit of its discharge stroke, the air-valve assembly <NUM> redirects pressurized air to the back side of diaphragm 202B. The pressurized air forces diaphragm 202B away from the center of pump <NUM> while pulling diaphragm 202A towards the center of the pump. Diaphragm 202B is now on its discharge stroke. Diaphragm 202B provides hydraulic forces against the liquid in chamber 204B forcing a discharge valve ball off its seat and the liquid through the pump outlet.

Because diaphragms 202A and 202B form separation membranes between the compressed air and the liquid, a diaphragm leak or rupture can introduce air and impurities into the liquid and cause the liquid to be discharged out of the pump's air exhaust. This can contaminate the liquid and present hazards to personnel. For example, leak or rupture in one of the diaphragms 202A or 202B can cause air, and possibly impurities from the air, to be introduced into the liquid during the high-pressure discharge, stroke potentially contaminating the liquid. Moreover, a leak or rupture in one of the diaphragms 202A or 202B can draw the liquid into the air-valve assembly <NUM> during the low-pressure suction stroke. The liquid may then become entrained in the flow of exhaust air and spray or leak out of the pump <NUM> through the muffler <NUM>.

Referring again to <FIG>, in the air-operated pumping system <NUM>, muffler plate <NUM> is attached to the air valve assembly <NUM>. Muffler plate <NUM> provides a connection interface to the exhaust of the air valve assembly <NUM>. In some implementations, muffler plate <NUM> is integrated into air valve assembly <NUM>. Leak detection device <NUM> is coupled to the muffler plate <NUM>. Leak detection device <NUM> can be directly coupled to muffler plate <NUM> or coupled through a fitting piece <NUM>. Muffler <NUM> is connected to an outlet of leak detection device <NUM>. However, in alternate implementations leak detection device <NUM> can be connected directly to the air valve assembly <NUM>. For example, the air valve assembly <NUM> can have a connection interface on the exhaust outlet.

In some implementations, as illustrated in <FIG>, the system <NUM> is configured such that the air valve assembly's <NUM> exhaust outlet is substantially aligned with the inlet to the muffler <NUM> through leak detection device <NUM>. In other words, an air flow path from the air valve assembly exhaust through leak detection device <NUM> and into muffler <NUM> is a substantially straight flow path.

<FIG> depict various views of the leak detection device <NUM>. <FIG> depicts a top cross-sectional view of the leak detection device <NUM> taken at axis A-A'. <FIG> depicts a side cross-sectional view of the leak detection device <NUM> taken at axis A-A'. And, <FIG> depicts an exploded diagram of the leak detection device <NUM>.

Referring to <FIG>, leak detection device <NUM> includes a body <NUM>, a liquid separator <NUM>, and a liquid level detector <NUM>. Leak detector body <NUM> has an airflow inlet <NUM> and an airflow outlet <NUM>. Airflow inlet <NUM> and airflow outlet <NUM> are arranged on body <NUM> to be substantially aligned with each other on opposite sides of the body <NUM>. For example, such an arrangement provides a substantially straight flow path from the air exhaust outlet <NUM> through the leak detection device <NUM> and into the inlet <NUM> of muffler <NUM>. For example, the airflow path follows generally along axis A-A'.

Liquid separator <NUM> is positioned directly in the airflow path to, for example, obstruct the flow of any entrained equated within the exhaust air. In other words, liquid separator <NUM> is positioned within body <NUM> directly between the airflow inlet <NUM> and the airflow outlet <NUM>. Liquid separator <NUM> provides a direct air impingement surface <NUM> within the airflow path between the pump's air exhaust and the inlet <NUM> to muffler <NUM>. Liquid separator <NUM> causes heavy liquid particles that may be entrained in the exhaust air (e.g., from a diaphragm leak) to fall out of the air flow when they impact the impingement surface <NUM>, and diverts the exhaust air along flow paths between the liquid separator <NUM> and the inner surface of the body <NUM>.

As illustrated in <FIG>, liquid separator <NUM> has a generally circular cross-section along the airflow path (e.g., axis A-A'). However, in other implementations, liquid separator <NUM> can be formed with a different shaped cross-section. For example, liquid separator <NUM> can be formed with a teardrop shaped cross-section. In such implementations, liquid separator <NUM> can be oriented with the narrow portion of the teardrop shape directed towards the outlet <NUM> and the portion of the teardrop shape directed towards the inlet <NUM> to act as the air impingement surface.

A liquid reservoir <NUM> is formed in a lower portion of body <NUM>. As entrained liquid is removed from exhaust air by impingement against liquid separator <NUM> it flows down along the side of liquid separator <NUM> and into the liquid reservoir <NUM> where the liquid collects. Liquid level detector <NUM> is at least partially contained within a channel <NUM> defined within a lower portion of liquid separator <NUM>. The channel <NUM> is in fluid communication with the reservoir <NUM>. As liquid collects in reservoir <NUM>, the level of the liquid rises within channel <NUM>. Liquid level detector <NUM> will be activated once the liquid collected in reservoir <NUM> reaches a level that triggers the liquid level detector <NUM>. Once triggered, liquid level detector <NUM> provides an electrical output signal indicating a diaphragm leak in the pump.

Liquid level detector <NUM> can be implemented as, an electronic liquid level sensor, an optical liquid level sensor, or a float switch, for example. As illustrated, liquid level detector <NUM> is implemented as a float switch assembly with a float <NUM> operably coupled to a flow sensor <NUM>. Liquid level detector <NUM> includes an electrical output connector <NUM> through which liquid level detector <NUM> provides electrical output signals. For example, liquid level detector <NUM> can be connected to a pump monitoring system, which, upon receipt of an activation signal from the level detector, can initiate a pump leak alarm. In some examples, electrical connector <NUM> can be a waterproof electrical connector.

In some implementations, leak detector body <NUM> includes an upper housing <NUM> and a lower housing <NUM>. The leak detector inlet <NUM> and outlet <NUM> are formed in the upper housing <NUM>. Lower housing <NUM> can form the liquid reservoir <NUM>. Upper housing <NUM> and lower housing <NUM> can be separable to permit cleaning or maintenance of the leak detector. For example, upper housing <NUM> can include coupling posts 410A arrange to mate with a coupling flange 410B on lower housing <NUM>. Lower housing <NUM> is fastened to upper housing <NUM> by mechanical fasteners <NUM>. For example, coupling posts 410A can be threaded to receive threaded fasteners <NUM>. An O-ring 340C can be disposed between upper housing <NUM> and lower housing <NUM> to provide a liquid tight seal.

In some implementations, liquid separator <NUM> includes an upper portion <NUM> and a sleeve <NUM>. Upper portion <NUM> mates with an upper surface of the body's upper housing <NUM>. Furthermore, upper portion <NUM> can include a cylinder that extends from the upper portion <NUM> into the airflow path through body <NUM>. The cylinder forms the air impingement surface <NUM>. Level detector <NUM> can also be coupled within a channel through the upper portion <NUM> of liquid separator <NUM>. For example, level detector <NUM> can be attached to the bottom of the liquid separator's upper portion <NUM> and extend into the channel <NUM> defined within air separator sleeve <NUM>. The top end of sleeve <NUM> mates to the bottom end of upper portion <NUM>. In some examples, an O-ring 340A is disposed between the upper portion <NUM> of air separator <NUM> and the upper surface of the body's upper housing <NUM>. In some examples, an O-ring 340B is disposed between air separator sleeve <NUM> and air separator upper portion <NUM>.

In some implementations, lower housing <NUM> is formed with a shelf <NUM> at an upper end of reservoir <NUM>. The shelf <NUM> includes one or more drain channels <NUM>. For example, shelf <NUM> can include two, three, four, five, or any appropriate number of drain channels <NUM>. In addition, air separator sleeve <NUM> is formed with a tapered flange <NUM>. The tapered flange <NUM> can be configured to extend at least partially over shelf <NUM>. For example, tapered flange <NUM> can form a covering over reservoir <NUM> to isolate liquid contained in reservoir <NUM> from exhaust air flowing through the upper housing <NUM>. In some examples, the tapered flange <NUM> is configured to rest on the shelf <NUM> of the lower housing <NUM>. For example, the tapered flange <NUM> can be sized such that a bottom surface <NUM> of the flange rests on the shelf <NUM> of lower housing <NUM>.

The drain channels <NUM> permit the liquid removed from the exhaust air by the liquid separator <NUM> to flow underneath tapered flange <NUM> and into the reservoir <NUM>. This configuration may prevent liquid contained in the reservoir <NUM> from being re-entrained into exhaust air flowing through leak detection device <NUM>. In some examples, the air separator sleeve <NUM> includes one or more vent holes <NUM> to, for example, allow air to exit the channel <NUM> as liquid drains into the reservoir <NUM>.

In some implementations, lower housing <NUM> can be made of a transparent material to, for example, permit visual inspection of any liquid contained in reservoir <NUM>. In some implementations, only the portion of lower housing <NUM> that forms reservoir <NUM> is made of a transparent material. In some of the limitations, lower housing <NUM> can include windows to permit viewing of any liquid contained in reservoir <NUM>.

In operation, leak detection device <NUM> receives exhaust air from an air-operated diaphragm pump <NUM>. Leak detection device <NUM> removes liquid entrained in the exhaust air by a direct impingement device (e.g., liquid separator <NUM>) positioned to direct a flow of the exhaust air into at least two separate flow paths around the direct impingement device. Leak detection device <NUM> directs the exhaust air towards an air impingement surface <NUM> of the direct impingement device, where impingement of the exhaust air on the direct impingement device removes entrained liquid from the exhaust air. Liquid can also be removed from the exhaust air impinging on the internal surface of the body <NUM>. Leak detection device <NUM> directs the liquid into a liquid reservoir <NUM> positioned below the direct impingement device. For example, tapered flange <NUM> directs the liquid through drain channels <NUM> in the body <NUM> and into reservoir <NUM>. Leak detection device <NUM> provides a leak indication signal responsive to activation of liquid level detector <NUM> that is at least partially contained within channel <NUM> defined by a lower portion of the direct impingement device (e.g., sleeve <NUM>).

As used herein, the terms "orthogonal" or "substantially orthogonal" refer to a relation between two elements (e.g., lines, axes, planes, surfaces, or components) that forms a ninety degrees (perpendicular) angle within acceptable engineering, machining, or measurement tolerances. For example, two surfaces can be considered orthogonal to each other if the angle between the surfaces is within an acceptable tolerance of ninety degrees (e.g., ± <NUM>-<NUM> degrees).

As used herein, the terms "aligned," "substantially aligned," "parallel," "substantially parallel," "flush," or "substantially flush" refer to a relation between two elements (e.g., lines, axes, planes, surfaces, or components) as being oriented generally along the same direction within acceptable engineering, machining, drawing measurement, or part size tolerances such that the elements do not intersect or intersect at a minimal angle. For example, two surfaces can be considered aligned with each other if surfaces extend along the same general direction of a device. Similarly, two surfaces can be considered to be flush or substantially flush if both surfaces generally lie within the same plane, but may a slight offset that is within acceptable tolerances may still exist between the surfaces.

Claim 1:
A diaphragm pump leak detection device (<NUM>) comprising:
a body (<NUM>) comprising
an airflow inlet (<NUM>),
an airflow outlet (<NUM>) arranged to substantially align with the airflow inlet, and
a liquid reservoir (<NUM>) in a bottom portion of the body;
a liquid separator (<NUM>) positioned directly between the airflow inlet and the airflow outlet, the liquid separator dividing an airflow path from the airflow inlet to the airflow outlet into at least two separate flow paths around the liquid separator, wherein the liquid separator (<NUM>) comprises
a cylinder coupled to the body and positioned directly between the airflow inlet and the airflow outlet, and
a sleeve (<NUM>) configured to interface with a lower portion of the cylinder, the sleeve comprising a channel (<NUM>), wherein a first end of the channel terminates at the lower portion of the cylinder and a second end of the channel opens to the liquid reservoir; and
a liquid level detector (<NUM>) at least partially contained within the channel (<NUM>), wherein the channel is in liquid communication with the liquid reservoir.