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CAEP Logistics Cart Project

Background:

The Centralized Research Support Facility (CRSF) at UCSD has streamlined the cleaning process of animal equipment for the Animal Care Program on campus. Since its establishment, the CRSF has saved around 13 million dollars by consolidating facility space. Rather than establishing separate cleaning facilities for the campus's over 40 vivariums, the CAEP (Center for Automated Equipment Processing) under the CRSF provides a central area for all cleaning to take place. This has freed up a considerable amount of facility space for vivarium technicians to use for other functions. Other benefits of the CAEP include consolidated cleaning costs, efficient vivarium staff assignment, and lower manpower requirements for cleaning. The CAEP currently uses automated cleaning through a rack washer, smaller tunnel washer for individual components, and a conveyor washer.

Project Objective:

Currently, technicians at CAEP use baker carts known as "Mules" to hold cage components in nested configurations. These carts are carried directly to and from vivariums for technician use and cleaning. Components on the mule must be unloaded from their nested configurations and loaded onto cleaning racks before entering the rack washer in the facility. After cleaning, components must be re-nested before the cart can be wrapped and sent out for vivariums use. This entire process takes over an hour or more depending on how many technicians are working. The goal of the CAEP project is to build a new cart that can both hold components compactly and also run through the washers. This would achieve the facility's goal of a "one-touch process", where there is minimum technician handling of components in the cleaning process. The new cart should be both ergonomic for technician use and able to achieve acceptable levels of cleaning for the facility's wide variety of components. We are naming our new cart prototype the "Buffalo"                                                                 

                    "The Mule"                                             Compiled Dirty Cages

Design Overview:

The cart prototype uses a multi-tiered design, with each tier consisting of a circular basket where components are to be arranged in a circular fashion. Components are secured  in each basket with cable vertically for them to sit between. The circular baskets are to rotate on a bearing when inside the conveyor washer, allowing for even water exposure for a thorough clean. Baskets are held in between 4 support poles for technicians to hold onto during cart transportation. These poles also serve to hold crossbars that support the baskets from below. Baskets all feature a grid pattern to allow water exposure from the floor sprayers and for water to drain after wash. The design also features 2 centripetal brakes to prevent the cart from spinning too quickly, which would lower the exposure time of water hitting the components. 

CAD of Buffalo Prototype

Design Functionality:

Prototype testing was completed at the facility gather data on optimal component orientation and basic cleaning functionality. Components were secured using twine, a substitute for the cable during early testing phases.  

                                  Prototype with Components loaded

After testing different parameters, such as spin speed and orientation of components, we determined that lid components would clean regardless of spin and orientation, but wire bars were much trickier to clean. Our optimal cleaning set-up is a slowed spin with any orientation for the wire bars.

Performance Results of  Final Prototype:

The final prototype was sent through the conveyor washer for analysis of cleaning and rotation speed. An accelerometer was placed on the prototype during the wash to gather rotation data.

Accelerometer tupperware set-up                                            Buffalo prototype entering conveyor wash

 The prototype is capable of loading a total of 100 components (20 components per layer). The components tested with riboflavin all showed satisfactory cleaning results. The accelerometer measured a rotation speed of 36 RPM inside the wash. 

Washing functionality aside, the cart is heavier and a little more awkward to transport than the current mule carts in use. However, these carts do not require technicians to load and unload components before and after transportation from vivariums. Unlike the mules, the buffalo can be used in the conveyor washers, increasing the overall output of cleaned components for CAEP. 2 buffalo carts can also be loaded in the rack washer at a time. 

Executive Summary:

See: https://docs.google.com/a/ucsd.edu/viewer?a=v&pid=sites&srcid=ZW5nLnVjc2QuZWR1fDE1NmItMjAxOS13aW50ZXItdGVhbTA3fGd4OjZjMDJjYWU5NDlhOTQ3ZDg