Small Bore Diaphragm Air Cylinders

Marsh Bellofram Small Bore Diaphragm Air Cylinders are actuators made from elastomers, engineered metals and fabrics. They require no lubrication and are virtually frictionless and economical. They can be used to provide lifting, clamping, pushing, coining, turning and other linear force or actuation motions in many applications.

The development of the long stroke rolling diaphragm for dynamic sealing has been field-proven as a reliable solution for many applications requiring low friction, no lubrication, low leakage, wide temperature variations and low total cost of ownership. The popularity of the rolling diaphragm as a sealing means led to many requests for a standard line of “off the shelf” diaphragm cylinders; single and double acting, short and long stroke with a wide selection of effective areas. To meet these requests, the long stroke rolling diaphragm cylinder was developed; Marsh Bellofram has supplied many thousands of them since their 1965 introduction. Bellofram’s 0.38 and 1.7 sq. inch effective area diaphragm cylinders combine the performance of the diaphragm cylinder with small size. Two different stroke options are available in each size, with either flush or extended rods on 0.38 sq. inch cylinders. Only spring return varieties are available.



  • Very smooth, “Non-Jarring” action
  • Compact Sizes
  • Low Hysteris
  • Perfect for OEM’s
  • Many Mounting Options