Rust No More
Hospitals should be sterile. Especially when the equipment is delivering medically pure water. When Mar Cor came to Priority Designs, the current cart for transporting reverse osmosis (RO) equipment for hemodialysis was clunky, but worst of all it was rusting and eroding.
Hemodialysis is a procedure performed in hospitals and clinics for ongoing treatment of kidney failure to purify the patient’s blood. As our team went out to observe the product through contextual research, it was clear that the carts used to carry RO machines are often very heavy and challenging for nurses to maneuver through hallways and small hospital rooms.
The project began with a goal to design a plastic cart that would not rust, but also to make design decisions that would improve the usability and experience for nurses administering care.
Designing an Experience
As the team designed around a plastic injection molded material, cart features and placement of the RO machines were thoughtful and purposeful. Hoses, cords, wires and other equipment are concealed in compartments for easy access and maintenance, while frequently used components are open and accessible for a simple and clear experience.
To improve maneuverability, the rounded outer edge can be easily pushed or pulled from any direction, and the bottom bumper is designed to withstand bumps through the halls and allows nurses to quickly push through doors.
Throughout the process, designers worked closely with our engineers and prototyping shop to evaluate ideas and evolve the design quickly. Due to the tight spaces where the cart is used, the user needs to be able to see the RO machine interface from a close distance. When pushing the cart, the user also needs to be able to see over the front edge.
Early prototypes revealed that sightlines were obstructed during maneuverability. Designs and form lines were refined to ensure that users of varying heights would be able to view and use the cart effectively.
The top and front of the cart are the primary places for nurse interaction. During initial observation of the user, our team saw that the nurses often use the cart as a workspace during patient care due to limited space. The top of the cart is designed as a flat workspace with a small compartment to bring along medications or other supplies to help maximize efficiency during patient care. The front of the machine clearly displays readings of the water purification to verify and record. Three test ports are prominently placed with an added drip tray to catch any excess and avoid messes.
Everything in its Place
Each part of the cart housing was engineered to be reaction injection molded. The structural piece was manufactured with a complex 6-pull direction in a single piece. Engineers carefully planned the assembly of the components, wire organization within the enclosure, and component organization from the top and side of the cart. With each item in its place, maintenance can be performed easily while being safely tucked away from everyday use.
Iterate, Refine, Rinse and Repeat
In addition to designed usability, the cart is engineered to be resilient and safe for transporting equipment through hospital environments. The Priority Designs team conducted FEA to verify the strength of the cart bumper and ensure it could withstand expected hits without breaking or cracking. FEA was also used to verify structural support of the weight of the equipment. To evaluate safety when pushing the cart through halls or onto elevators, engineers calculated the center of mass and balance weight to confirm that the cart could pass the threshold without tipping over.
Prior to manufacturing handoff, engineers performed tolerance analysis on parts that would fit together in production. With tool-ready CAD and 2D documentation drawings, Priority Designs provided a smooth and successful transition into production.
From start to finish, prototyping played an integral role in testing and refining form, aesthetics and component placement. The process began with a quick, inexpensive proof-of-concept model from MDF to test size and shape and get a quick understanding of the design. Next, an appearance prototype was created to refine the design and continue iterations of form.
Once form and aesthetics were established, a functional engineering prototype helped refine the assembly and equipment organization in the internal compartments.
To create the appearance prototype, foam was CNC machined in-house and carefully finished. Parts were assembled and painted to look just like the final production product. From the appearance model, designers discovered that sightlines were obstructed and needed to be adjusted. Usability was tested and the design was revised and improved for the final prototype.
To create the appearance prototype, foam was CNC machined in-house and carefully finished. Parts were assembled and painted to look just like the final production product. From the appearance model, designers discovered that sightlines were obstructed and needed to be adjusted. Usability was tested and the design was revised and improved for the final prototype.
Safe, Clean, and Streamlined
The refined Mar Cor Rover Dialysis Water Transport System provides a streamlined solution for both production and user. The single part reaction injection molded solution reduced assembly time and inventory space needed. Detailed engineering handoff to production helped Mar Cor avoid part tolerance issues for a faster production timeline.
The new cart’s durable enclosure is not only clean and rust-free, but designed to house varying sizes and types of RO machines. With each machine, the same simplified user experience is provided with a front accessible interface.
Through integrated teamwork from Priority Designs’ design, engineering, and prototyping, the final solution delivers enhanced safety, durability and cleanliness. By improving the design for user efficiency, hospitals and clinics are experiencing increased productivity with a more reliable product.
