Figure 1. Quick-acting couplings created for Sunrise Medical can be disconnected under pressures from 1800 to 2200 psi.
Figure 2. This rocking piston pump from Gast Mfg. is capable of 31 psi maximum pressure, 20.5 in-Hg. maximum vacuum, and 14.7 lpm open flow.
Healthcare has been a fast-growing field, and there is little evidence that it will slow in the coming years, as the Baby Boomers reach retirement age. The U.S. Bureau of Labor Statistics reports that education and health services will grow faster (by 30.6%) and add more jobs than any other sector through 2014.
As with any growing market, new technology is constantly vying for a piece of the proverbial pie. Here's a look at some interesting medical marvels in which pneumatics is playing a role.
Custom couplings to the rescue
Oxygen patients no longer have to rely on the delivery of pre-filled cylinders. A new transfill system from DeVilbiss generates oxygen via a concentrator and uses a compressor to fill mobile cylinders — cylinders that users can refill at home.
According to the American Lung Association, more than one million Americans have medical conditions that require the use of supplemental oxygen in order to engage in routine daily activities.
Sunrise Medical, one of the world's largest manufacturers of homecare and extended care products, sells a wide range of home respiratory systems under the DeVilbiss brand. Sunrise set out to develop an integrated compressed oxygen system to allow patients to easily refill their mobile cylinders at home. The new system was designed to eliminate the disruption to daily life.
"The transfill systems that were on the market were pretty intrusive for patients," said Sunrise vice president of product development Tim Walsh. "They were heavy, bulky, loud, and placed right next to the patient. So we decided to develop a smaller, quieter hybrid system that quickly fills mobile cylinders to give patients more freedom and home oxygen providers streamlined delivery. The unit can be placed in a separate room away from the patient."
In order to pull the system together, Sunrise called on Parker's Quick Coupling Div. to develop a non-interchangeable quick disconnect coupling that could handle oxygen service up to 2000 psi, and connect and disconnect under pressures from 1800 to 2200 psi. The 2200 psi specification was presented by Sunrise as an extra safety measure. The pressure transducer that initiates the automatic shut off feature allows a certain percentage of air in its tolerance. Sunrise wanted to ensure safe operation even if the calibration was off, so they specified the coupling to operate at a higher pressure than necessary.
The specifications could not be met by any products in the current product offering, so the engineers at Parker started working on a custom solution.
Six months later, Parker delivered a custom, cone-shaped bottle nipple that allows the patient to easily connect and disconnect mobile cylinders for refilling, Figure 1. The couplings were designed to allow the mobile cylinders to be connected with just one hand. The coupler also has an integrated electrical switch to control the delivery of oxygen from the unit to ensure safe operation. An orifice on the coupling valve automatically releases pressure upon disconnection.
The main body components of both the coupler and nipple are brass. The internal components are comprised of brass and stainless-steel and use Parker's elastomeric seals and PTFE rings. The coupler sleeve and the extension tube are manufactured by Parker from engineered acetal. All materials were selected to ensure leak-free oxygen service.
"The new coupler was designed with safety and ease of use in mind," commented Parker project engineer Shawn Ellis. "Since the system will be used at home, we wanted to make sure patients could easily connect and disconnect the mobile cylinders."
New pump a possibility for multiple medical applications
Gast Mfg. Inc. recently introduced a new addition to their rocking piston line, the 20R Series, Figure 2. This cost effective, maintenance free, durable plastic pump with UL/FDA approval was designed with lower current draw and increased flow. It is capable of 31 psi maximum pressure, 20.5 in-Hg. maximum vacuum, and 14.7 lpm open flow.
Oilless, motor mounted, and with full ball bearing construction, the pump can be used in a wide range of applications but was designed for the demands of the medical industry. With multiple stroke, motor options, and barbed port locations available, it can be used worldwide. Gast says that the pump can be used in a variety of medical applications, including nebulizers, aspirators, blood pressure machines, and pneumatic pads.
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