Patent Application
20170050226
The present invention relates to a system and method for measuring characteristics of a fluid with levels of contamination or fouling agents, and more particularly to a method and system for cleaning and maintaining the cleanliness of in-process sensors.
Reducing the reliance on imported fossil fuels is significant for the future and various attempts have been made to develop a renewable placement from non-petroleum sources. Possible supplements for fossil fuels are biofuels such as ethanol, biodiesel, green diesel, and biogas, all of which are produced by biological cultivation systems. Examples of biological cultivation systems include the production of ethanol from corn, the production of biodiesel from vegetable oils, the production of biogas from animal manure, and the production of green diesel from algae. Using algal culture systems is advantageous as a fuel supply due to the fast growth rate and simple nutritional requirements of algae. Algal culture systems may also be used to supply food or diet supplements, generally replacing oils. Algae cultivation may use conventionally non-arable land and varieties of algae may be adapted to fresh or salt water. Algae cultivation, or algaculture, systems are generally one of three types: open ponds, semi-open photo-bio-reactors or closed photo-bio-reactors. Algaculture may be done at a low cost, but requires copious amounts of water and growers must monitor water quality and biological parameters to ensure optimal growth conditions. Thus, algae cultivation requires robust monitoring equipment that withstands environmental loads specifically related to algae. In-process sensors are generally used to interact with a process fluid to measure parameters related to water quality and growth.
The use of in-process sensors, however, has drawbacks. Bio-fouling of sensors is a problem in algaculture and traditional water quality. Normal operation of such sensors typically requires the surface of the sensor be free of contaminants, such as organic growth, solids, films or coatings, as well as sediment and other debris, in order to take accurate measurements. These conditions are referred to as ‘fouling’ of a sensor when inaccurate measurements are made. Some methods for cleaning in-process sensors require removing the sensor from service, which is time consuming and causes damage to the equipment. Other methods include using a cleaning agent, such as clean water, acids, detergents or air bubbles, which introduce undesirable material foreign to the process stream, risking damage to the algae cells.
The present invention provides a monitoring system that maintains clean instruments without introducing cleaning agents or additional fluid volume to the system. The present invention eliminates a need for multiple branches for fluid movement in order to measure a fluid sample and clean the sensor.
A self-contained system for monitoring a process fluid may include at least one housing defining a sensor chamber configured to receive a flow of the process fluid, a sensor positioned within the sensor chamber and having a contact surface configured to measure a fluid characteristic of the process fluid, an injection nozzle having an inlet fluid passage receiving a predetermined amount of process fluid and an outlet fluid passage discharging the predetermined amount of process fluid into the sensor chamber, and a drain passage for removing the predetermined amount of process fluid from the sensor chamber. The injection nozzle is positioned at an oblique angle relative to the contact surface such that the contact surface is impinged by the process fluid, wherein impingement by the process fluid against the contact surface of the sensor allows measurement of the process fluid by the sensor and cleans the contact surface.
A method of self-cleaning a sensor in a monitoring assembly for a process fluid may include receiving a predetermined amount of process fluid into an inlet fluid passage of an injection nozzle, injecting the predetermined amount of process fluid from an outlet fluid passage of the injection nozzle into a sensor chamber housing the sensor, and removing the predetermined amount of process fluid from the sensor chamber via a drain passage. The sensor includes a contact surface for measuring a fluid characteristic of the process fluid and the contact surface is self-cleaned by impingement of the process fluid at an oblique angle from the injection nozzle.
These and further features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the claims appended hereto. Features that are described or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments or in combination with or instead of the features of the other embodiments.
The principles of the present invention have particular application to biological cultivation systems. An example of such a biological cultivation system is an algae cultivation system. The present invention pertains to a self-contained monitoring system for monitoring a process fluid having a closed loop of fluid flow. The self-contained monitoring system includes at least one housing defining a sensor chamber configured to receive a flow of the process fluid, a sensor positioned within the sensor chamber and having a contact surface configured to measure a fluid characteristic of the process fluid, and an injection nozzle having an inlet fluid passage for withdrawing a process fluid from the fluid source and an outlet fluid passage for discharging the process fluid into the sensor chamber, and a drain passage for returning the entire amount of the extracted process fluid to the fluid source. The injection nozzle is positioned at an oblique angle relative to the contact surface of the sensor such that the contact surface is impinged by the process fluid. Impingement by the process fluid against the contact surface of the sensor allows measurement of the process fluid by the sensor and cleans the contact surface. Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale.
Referring first to
The injection nozzle 16 may emit process fluid into the sensor chamber 14 for both measurement of characteristics associated with the process fluid and reducing build-up of bio-film, sediment, debris, and/or other contaminants on a sensor 22 positioned within the sensor chamber 14. The injection nozzle 16 includes an inlet fluid passage 18 and an outlet fluid passage 20. The inlet fluid passage 18 may be positioned externally relative to the housing 12 and in fluid communication with a fluid source for withdrawing a predetermined amount of process fluid from the fluid source. The outlet fluid passage 20 may be positioned for discharging the predetermined amount of process fluid into the sensor chamber 14. The injection nozzle 16 may include at least one jet inlet 34 and at least one jet outlet 36 from which the process fluid is emitted. The jet outlet 36 may have a smaller diameter relative to the sensor chamber 14. The jet inlet 34 may be in fluid communication with the process fluid directly from the fluid source and may be adjustable to control the flow rate of the process fluid emitted into the sensor chamber 14.
Referring now to
The contact surface 24 of the sensor 22 may be positioned relative to the outlet fluid passage 20 of the jet outlet 36 such that a discharged predetermined amount of process fluid impinges on the contact surface 24. The injection nozzle 16 may be positioned at an oblique angle relative to the contact surface 24 such that impingement by the process fluid against the contact surface of the sensor allows measurement of the process fluid by the sensor. An advantage of such configuration is that the contact surface 24 of the sensor 22 is self-cleaned by impingement of the moving fluid. The distance of the jet outlet 36 relative to the sensor 22 may be modified based on the geometry and dimensions of the injection nozzle 16. A preferred distance between the jet outlet 36 and the contact surface 24 of the sensor 22 is approximately between 0.50 inches and 0.80 inches. The angle at which the process fluid may impinge on the contact surface 24 is an oblique angle. The preferred angle is approximately 35° where 0° is parallel to the contact surface 24 and 90° is perpendicular to the sensor surface. The angle may be approximately 20° to 45°. Angles of less than 45° are desirable because the flow trajectory will accommodate greater variety in sensor geometry. Angles of greater than 45° will provide efficiency in removal of debris and sediment from the contact surface. The preferred angle of 35° strikes a balance between cleaning performance and sensor compatibility. Flow through the injection nozzle 16 and sensor chamber 14 may be continuous, such that the predetermined amount of process fluid entering the sensor chamber 14 is approximately equivalent to the amount of process fluid exiting the sensor chamber 14.
The system 10 may include a first exemplary embodiment of the sensor 22 shown in
3.
The system 10 may further include a drain passage 26 for returning the predetermined amount of process fluid to the fluid source. The housing 12 may define an aperture 38 receiving a cartridge drain 40 defining the drain passage 26. The drain passage 26 and the sensor 22 may be positioned along a common longitudinal axis of the housing 12. The housing 12 may include a first end 42 and a second end 44 located distally opposite relative to one another. The cartridge drain 40 may be positioned at the first end 42 and the sensor 22 may be positioned at the second end 44 such that the drain passage 26 and the contact surface 24 of the sensor 22 are spaced apart relative to one another. Positioning the drain passage 26 directly below the contact surface 24 allows approximately an entire amount of the process fluid emitted into the sensor chamber 14 to return to the fluid source from which it was withdrawn, preventing accumulation of sediment at the first end 42 of the housing 12. The drain passage 26 may be throttled for controlling an amount of process fluid located in the sensor chamber 14 and maintaining that the sensor 22 is submerged. While this embodiment locates the drain passage coaxially with the sensor, it should be noted that locating the drain passage at the lowest point of the sensor chamber is the principle design criteria for effective removal of sediment from the sensor chamber, due to gravity.
Referring now to
Each of the plurality of housings 12 may include a sensor chamber 14 and sensor 22 having a probe as described herein for measuring one or more characteristics of the process fluid received in each of the plurality of housings 12. The system 10 may further include an output screen 56 for displaying measured data corresponding to the characteristic(s) of the process fluid as measured by the sensor 22. The output screen 56 may be an LCD screen, but may also include wireless communication or a wired output to an auxiliary display and recording device. Each of the drain passages 26 associated with the corresponding housing 12 may be in fluid communication with the outlet fluid passage 52 for returning the process fluid from each of the corresponding sensor chambers to the fluid source. The drain passages 26 may be in fluid communication with the outlet fluid passage 52 through a plurality of second fluid passages 54 corresponding to the plurality of housings 12. In an exemplary embodiment, the system 10 may include one inlet fluid passage 46, one outlet fluid passage 52, and a plurality of first and second fluid passages 50, 54 in fluid communication between the inlet and outlet fluid passages 46, 52 and the plurality of housings 12.
The housing 12 may be formed of a suitable material. An example of a suitable material is plastic. The housing 12 may also be formed by a suitable manufacturing process. An example of a process for forming a plastic housing injection molding. The housing 12 may be formed to have a press-in cartridge portion 62 at the second end 44 of the housing 22. The sensor 22 may include a threaded portion engageable with the press-in cartridge portion 62 of the housing 12 for ease in assembly. The housing 12 may include an o-ring seal 64 sealing the outlet fluid passage 20 of the injection nozzle 16 and the inserted drain cartridge located at the first end 42 of the housing 12. The housing 12 may additionally be mounted within a self-contained unit 58 via a mount 66. It should be recognized that any suitable mount may be implemented.
Referring now to
A method of self-cleaning a sensor in a monitoring assembly for a process fluid may include receiving a predetermined amount of process fluid into an inlet fluid passage of an injection nozzle, injecting the predetermined amount of process fluid from an outlet fluid passage of the injection nozzle into a sensor chamber housing the sensor, and removing the predetermined amount of process fluid from the sensor chamber via a drain passage. The sensor may include a contact surface for measuring a fluid characteristic of the process fluid and the contact surface may be self-cleaned by impingement of the process fluid at an oblique angle from the injection nozzle. The method may further include positioning the injection nozzle at an angle ranging between 20° and 45°, where 0° is parallel to the contact surface and 90° is perpendicular to the contact surface. The preferred angle may be 35°. The method may further include positioning the drain passage and the sensor along a common axis of the sensor chamber, where the drain passage is located directly below the sensor and spaced apart from the contact surface of the sensor. The method may further include displaying a measured value of the fluid characteristic of the process fluid on an LCD screen and adjusting the injection nozzle to control a flow rate of the predetermined amount of process fluid into the sensor chamber. The process fluid in the self-cleaning method may be withdrawn from an algae cultivation pond.
A self-contained monitoring assembly for monitoring a process fluid comprises at least one housing defining a sensor chamber configured to receive a flow of the process fluid, a sensor positioned within the sensor chamber and having a contact surface configured to measure a fluid characteristic of the process fluid, an injection nozzle having an inlet fluid passage receiving a predetermined amount of process fluid and an outlet fluid passage discharging the predetermined amount of process fluid into the sensor chamber, the injection nozzle positioned at an oblique angle relative to the contact surface such that the contact surface is impinged by the process fluid, and a drain passage for removing the predetermined amount of process fluid from the sensor chamber. Impingement by the process fluid against the contact surface of the sensor allows measurement of the process fluid by the sensor and cleans the contact surface by simultaneously reducing and removing debris build up.
The self-contained monitoring assembly may include the inlet fluid passage positioned externally to the at least one housing. The injection nozzle may be positioned at an angle between approximately 20° and 45°, wherein 0° is parallel to the contact surface and 90° is perpendicular to the contact surface. The injection nozzle may be positioned at an angle of approximately 35°. The injection nozzle may be adjustable to control a flow rate of the predetermined amount of process fluid into the sensor chamber.
The drain passage may be positioned at a lowest point in the sensor chamber or at an end of the at least one housing spaced apart from the contact surface of the sensor. The drain passage and the sensor may be positioned along a common axis of the at least one housing. The drain passage may be throttled for controlling an amount of process fluid located in the sensor chamber.
The at least one housing may comprise a plurality of housings, where each of the plurality of housings have a corresponding injection nozzle, sensor, and drain passage.
The sensor may be configured to measure a fluid characteristic of the process fluid comprising at least one of pH, conductivity, temperature, dissolved gases and concentration of chemical components of the fluid. The sensor may include a body formed of a material resistant to microbial growth.
The sensor chamber may include an air bleed port for controlling fluid level in the sensor chamber.
A fluid monitoring system may include the self-contained monitoring assembly. The monitoring system may include a fluid source and the predetermined amount of process fluid is withdrawn from the fluid source. The monitoring assembly may be located remotely from the fluid source. The fluid source may be one of an algae cultivation pond, a wastewater flocculation and clarification tank, and an equalization tank for dewatering filtrate. The system may include a pump in fluid communication between the fluid source and the inlet fluid passage of the injection nozzle for pumping the predetermined amount of the process fluid from the fluid source to the nozzle.
The monitoring system may include an output screen for displaying a measured value of the fluid characteristic of the process fluid, wherein the output screen includes wireless communication or a wired output to an auxiliary display and recording device.
A method of self-cleaning a sensor in a monitoring assembly for a process fluid comprising the steps of receiving a predetermined amount of process fluid into an inlet fluid passage of an injection nozzle, injecting the predetermined amount of process fluid from an outlet fluid passage of the injection nozzle into a sensor chamber housing the sensor, the sensor having a contact surface for measuring a fluid characteristic of the process fluid, wherein the contact surface is cleaned by impingement of the process fluid at an oblique angle from the injection nozzle, and removing the predetermined amount of process fluid from the sensor chamber via a drain passage.
The self-cleaning method may further comprise positioning the injection nozzle at an angle between approximately 20° and 45°, wherein 0° is parallel to the contact surface and 90° is perpendicular to the contact surface. The method may further comprise positioning the injection nozzle at an angle of approximately 35°. The method may further comprise adjusting the injection nozzle to control a flow rate of the predetermined amount of process fluid into the sensor chamber.
The method may further comprise positioning the drain passage at a lowest point in the sensor chamber, where the drain passage is spaced apart from the contact surface of the sensor. The method may further comprise positioning the drain passage and the sensor along a common axis of the sensor chamber.
The method may further comprise displaying a measured value of the fluid characteristic of the process fluid on an output screen using wireless communication or a wired output to an auxiliary display and recording device.
The method may further comprise withdrawing the fluid from one of an algae cultivation pond, a wastewater flocculation and clarification tank, and an equalization tank for dewatering filtrate.
Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
| Number | Date | Country | |
|---|---|---|---|
| 62208034 | Aug 2015 | US |
