Diaphragm (mechanical device)

Abstract: A new valveless fluid pump has been designed and tested. The pump consists of two fluid diffuser/nozzle elements on each side of a chamber volume with an oscillating diaphragm. The vibrating diaphragm produces an oscillating chamber volume, which together with the two fluid-flow-rectifying diffuser/nozzle elements, creates a one-way fluid flow. A micropump prototype with a chamber diameter of 19 mm with conical diffuser/nozzle elements has been built and tested. The maximum liquid flow rate is 16 ml/min and the maximum pump pressure is 2 m H 2 O. The pump frequency is of the order of 100 Hz.

Abstract: The highly ordered, isoporous substructure of the glomerular slit diaphragm was revealed in rat and mouse kidneys fixed by perfusion with tannic acid and glutaraldehyde. The slit diaphragm was similar in both animal species and appeared as a continuous junctional band, 300–450 A wide, consistently present within all slits formed by the epithelial foot processes. The diaphragm exhibited a zipper-like substructure with alternating, periodic cross bridges extending from the podocyte plasma membranes to a central filament which ran parallel to and equidistant from the cell membranes. The dimensions and spacing of the cross bridges defined a uniform population of rectangular pores approximately 40 by 140 A in cross section and 70 A in length. The total area of the pores was calculated to be about 2–3% of the total surface area of the glomerular capillaries. Physiological data indicate that the glomerular filter functions as if it were an isoporous membrane which excludes proteins larger than serum albumin. The similarity between the dimensions of the pores in the slit diaphragm and estimates for the size and shape of serum albumin supports the conclusion from tracer experiments that the slit diaphragm may serve as the principal filtration barrier to plasma proteins in the kidney.

Abstract: A vaulted diaphragm for providing occlusion in a descending thoracic aorta, includes a flexible and substantially circular element, and a plurality of resilient ribs having inner and outer ends supporting the circular element. The inner ends of the ribs are joined together at a hub with the ribs extending radially outwardly therefrom. The ribs are generally positioned on and attached to the circular element with the outer ends of the ribs having protrusions projecting radially beyond the circular element. The ribs have a resilient expansion tendency, such that the diaphragm may be held in a biased folded position during installation and sprung open into a normally vaulted shape upon installation in the aorta, whereby the protrusions are urged radially outwardly by the resilient expansion tendency of the ribs to engage the aorta and hold the diaphragm in position. A surgical procedure for treating an aneurysm in a patient's descending thoracic aorta, includes the step of installing an artificial aorta by-pass connecting the patient's ascending natural aorta with the patient's abdominal aorta end. A temporary graft is installed onto the by-pass and a catheter having a capsule end holding a diaphragm is advanced through the graft. The diaphragm is positioned into a selected site in the aorta, and then released by ejecting it from the capsule and the catheter is withdrawn, with the diaphragm remaining within the aorta to provide an occlusion therein.

Abstract: A process device (10, 100) providing total fluid flow control is provided. The device (10, 100) includes a closure mechanism (12, 106) disposed in a flow conduit (16, 104) . The closure mechanism (12, 106), which is preferably an iris-type diaphragm, provides a variable internal diameter. The device (10, 100) includes a differential pressure sensor (20, 22; 120, 122) for sensing the differential pressure on opposite sides of the diaphragm. A controller (112) receives an indication of differential pressure and generates a control signal to an actuator that actuates the closure mechanism (12, 106). The closure mechanism (12, 106), differential pressure sensor (20, 22; 120, 122) and controller (112) create a closed-loop flow controller in a single process device (10, 100).

Abstract: An apparatus for training and treating the muscles of the female pelvic diaphragm and having a form corresponding to the vagina consists of an external shell (1) axially divided into a number of mutually separated segments (3-9) which are separately connected by connecting pieces (3'-9') formed as longitudinal cams to a displacement mechanism (10) mounted axially around a hollow shaft (12) inside the apparatus, said displacement mechanism being prevented from rotating around the shaft (12), and wherein a mechanical displacement of the mechanism (10) in one or the other axial direction through the connecting pieces (3'-9') as a result of the construction of the mechanism results in a radial movement of the segments (3-9), thereby dilating or retracting the shell (1).