Patent ID: 8381762

Claim:
A flow regulator for a wide range of low fluid flows, comprising: an inner non-revolving core element; an outer housing, having a hollow base section and being revolvably supported co-axially with said core element; first and second chambers disposed between said core element and said outer housing, each chamber having an inlet and an outlet, said outlet of said first chamber and said inlet of said second chamber being connected by a flow restriction path; an at least partly elastic diaphragm separating the two chambers and sealing an inlet to a discharge tube when pressure at said first chamber is higher than pressure in said second chamber, said diaphragm comprising an outer ring, a central disk, and a flexible intermediate section connecting said outer ring to said central disk; and a circular spring placed in the secondary chamber below said diaphragm and around said discharge tube; and said discharge tube inlet connected to said outlet of said second chamber when said central disk is spaced apart from said discharge tube inlet, and having a lower outlet connectable for infusion to a patient; a graduated flow-rate locking ring adapted to revolve for determining a flow rate of said regulator, said locking ring housing a disk-like body and a locking sleeve disposed between the outlet of said discharge tube and said base portion of said outer housing; and a lock key; wherein said lock key is adapted to be in a low position or in an upper position, wherein said locking ring is adapted to be in an open position or in a secured position, wherein said locking sleeve is adapted to be in an unlocked position or a permanently locked position, wherein when said locking ring is in said open position, said lock key is in said low position, and each of said outer housing and said locking ring are free to revolve; and when said locking ring is in said secured position, said lock key is raised to said upper position and said revolving of said outer housing is permanently restricted and said locking ring is secured at a selected flow rate, wherein said locking ring is free to move from said secured position to said open position and from said open position to said secured position, when said lock key is in said upper position, and wherein said locking sleeve is adapted to permanently lock said locking ring in said secured position when said locking sleeve is in said permanently locked position to permanently lock said selected flow rate.