Embedded Files
Sponsored by OceanWell, this project has focused on the biofouled intake systems of modern reverse osmosis technology. OceanWell is developing a subsea system that will provide an environmentally safe supply of filtered water for those that lack this necessity. These freshwater farms will be located 400 meters below the ocean surface; one issue with any undersea device is the accumulation of living debris, or biofouling, impeding function. This project’s motivation is to design a system to prevent the collection of biofouling that would clog OceanWell’s intake system.
The prototype consists of three testing parameters to identify the optimal method of cleaning biofouling. First, isolated brush cleaning focuses on using the rotational speed and engagement force of the brush to clean biofouled material. Next, isolated water jet cleaning sprays pressurized water at different angles with interchangeable nozzle head shapes (flat, cone, etc.) to clean. Finally, the combined method uses both brush and water jet cleaning.
The major components of this device include the linear motion frame, rotational element, and water jets as shown in Figure 1.
Figure 1 - Components of Poseidon’s Bidet
The linear motion frame is made from stainless steel channels and 3D printed plastic parts for corrosion resistance with an IP 67 waterproof stepper motor used to move the carriage. The rotating brush and the nozzles are mounted to the carriage of the linear motion frame so that they can be moved along in a linear direction to clean the test plate. The frame is also equipped with height adjusters to allow the vertical distance between the brush and the test plate to be changed, thus changing the engagement force of the brush.
The rotational element focused on adjustable speeds and interchangeable brushes. A gear reduction was implemented to reduce the RPM of the brush to a minimum of 32 to achieve similar speeds on the cleaning device of OceanWell’s intake system. For the design of interchangeable brushes a “One-Size-Fits-All” system was applied. Specifically, the brush attachments allow a maximum length of 241 mm (9.5 in) to fit between each L-bracket.
The water jet system was designed to provide three degrees of freedom. The height of the nozzles from the test plate are adjustable by using the height ladders which range from 0-120mm. The nozzle angle of attack with respect to the test plate can be adjusted by rotating the nozzle mount in 7.5o increments and using a pin to lock it in place with the ladder. Finally, the nozzle clips can rotate around the z-axis, so that a wider spray area can be covered.
After experiments using the three testing parameters, the cleanliness of each trial was measured by taking pictures of the test plate and using the software ImageJ for image processing to quantify the amount of biofouling cleaned. It was determined the brushes performed well against mock biofouling; in the case of the crayon trials, the brush method cleaned 97% while the water jet system cleaned 7%. In trials using real biofouling that had grown for between 4-6 weeks, which is assumed longer than the time the intake system would go without being cleaned, the combined method succeeded in clearing 100% of the biofouled material. Thus, the combined method performed as the best case method for clearing biofouling in this experiment.
PDF Executive Summary
PDF Executive Summary
Executive Summary.pdfPage updated
Report abuse