Key role for precision springs in medical applications that provide life support systems
It is generally acknowledged that manufacturers of medical and pharmaceutical equipment require precision components produced to strictly controlled specifications. Repeatability and reliability of stock and custom produced items are key issues in this sector where unerring quality standards are the norm.
Springs are found in innumerable applications in the medical sector, from insulin delivery through to surgical tools, equipment and wheelchairs.
Compression springs are the most common type used in medical and surgical equipment for fluid and motion control. Lee Spring has over 3500 Type 316 stainless steel stock compression springs in its portfolio of 15500 plus different products. Its stainless steel compression springs, passivated and ultrasonically cleaned instrument springs, Lite™ Pressure and standard compression springs have been used by leading international medical companies.
Design and manufacture
Alongside its stock range Lee Spring also designs and produces a huge variety of custom springs, including wire forms, washers, stampings and assemblies, many for the medical market. These ‘specials’ embrace every aspect of spring construction and performance and call upon the unique experience of spring engineers and technicians.
When specifying springs for these applications precision and performance are paramount but many other factors are critical too: for example, material choice, finishing and especially cleaning.
"We work closely with our customers to develop design specifications and products that meet or exceed their requirements and pride ourselves on the systems that we have implemented to ensure that we will achieve and maintain superior quality levels on all the products we provide,” says Sanjeev Rivera, Director of Sales and Engineering at Lee Spring Company’s main manufacturing centre in Brooklyn, USA.
Here, springs are produced on state-of-the-art manufacturing facilities that engage with lean manufacturing techniques. Both are essential to cover the complexities of spring manufacture and to maintain quality and competitive edge says the company.
Lee Spring’s production capability can handle wire diameters from 0.127 to 15.88 mm (0.005 to 0.625 ins) and includes in-house plating, ultrasonic cleaning, passivation, powder coating, heat treatment, polishing and assembly. Material options include music wire and a range of alloys including stainless steel 316 and 17-7, Inconel 600, phosphor bronze, beryllium copper and Hastelloy. Spring types manufactured are compression, die, extension, torsion, continuous length, belleville, battery, swivel hook, conical, drawbar, wave and constant force – excluding custom forms.
The company has ISO 9001 2000 recognition and is committed to RoHS standards at its seven plants in the Europe, Asia, North & South America.
Applications
In Europe Lee Spring’s torsion and extension springs are used in pharmaceutical delivery systems for fluid control valves used to deliver intravenous fluids, while standard compression springs find use in insulin dispensing automatic injection pens to control fluid delivery. The company’s Lite™ Pressure compression springs are used in pre-loaded syringes for the delivery of medication and in anaesthetic equipment where low pressure is required. Custom compression springs have been designed to aid the dispensing of pills for a proprietary birth control pill compact.
In medical equipment, compression springs are used in endoscopic biopsy devices for accurate tissue sampling. Surgical tools, for example staple guns, utilize many types of compression springs while surgical equipment applications include suction lines for body fluid recovery.
Other examples of spring fluid control applications include pneumatic and solenoid product lines used in critical applications, including:
Peritoneal and kidney dialysis machines to control fluid flow;
blood analysers to control test samples and fluids;
arterial catheterisation procedures to control saline flushing fluid;
multi-fluid drug delivery systems to control individual fluids; and
Peristaltic pump systems to handle on/off and emergency stop functions.
The following list is representative of the spread of current applications:
Pharmaceutical delivery systems
Syringes
Check valves
Pill dispensers
Pill counters
Fluid control
Intravenous valve controls
Pharmacy automation
Automated drug management
Liquid & dry powder inhalation devices
Insulin delivery
Medical/Surgical
Surgical tools & instruments
Staple guns
Orthopaedic tools
Suction lines
Catheter valves
Peristaltic pumps
Anaesthetic infusion
Sterilization valves
Shunt valves
Wheelchairs
Medical instrumentation
Diagnostics & monitoring devices