Ambulatory infusion membrane pump

Abstract

Ambulatory membrane pump intended for medical use e.g. for infusion purposes, consisting of two main parts: 1) the basic device with motor drive and computer, and 2) the administration set, which is disposable. The arrangement with check valves in both ends of the administration system safeguards that no leakage happens when gravitational forces are acting, due to height differences between fluid bag and needle.

1 . A membrane pump intended for transporting a controlled average of volumetric flow rate of a fluid from a fluid source through an outlet to a patient, the membrane pump comprising: 
 a pump house with a membrane,    a needle arrangement,    an inlet flexible tube connected to as inlet of said pump house,    an outlet flexible tube connected to an outlet of said pump house,    an inlet check valve connected to an end of said inlet tube and positioned close to the fluid source, and    an outlet check valve connected to an end of said outlet tube and positioned close to said needle arrangement.    
   
   
       2 . The membrane dump according to  claim 1 , further comprising: 
 (a) said inlet and outlet tubes having inner diameters between 0.4 and 2 mm,    (b) a box with an electric motor, wherein the pump house of the membrane pump is adapted to be docked to the box, and    (c) electric control means including the electric motor, a gear, a feeding screw and a piston for controlling the average volumetric flow rate by means of a control of the forward and backward movement of the piston.    
   
   
       3 . The membrane pump according to  claim 2 , wherein: 
 said membrane is yieldable and dimensioned for safely back springing and thus suction of the fluid into the pump house,    a boss provided with grooves is arranged on the center of the membrane, and said piston provided with a yoke gripping into said grooves and thus mechanically drives the membrane forwards and backwards.    
   
   
       4 . The membrane pump according to  claim 3 , wherein the electric motor and the gear are connected with the feeding screw and a threaded nut in combination with the piston for accomplishing the forward and backward movement, and wherein the piston is provided with splines fitting into an end plate of the box and wherein the piston is in contact with said boss of the membrane when the pump house is mounted on the box.  
   
   
       5 . The membrane pump according to  claim 4 , wherein the electric motor has a revolution registering device connectable to a control circuit, wherein said control circuit is provided with a display and keys for operating said feeding screw to order a decided stroke of the piston and said stroke being repeated until a new order is received from the control circuit, whereby the volumetric flow pumped with each stroke is controlled.  
   
   
       6 . The membrane pump according to  claim 5 , wherein said control circuit registers the content during a decided short time interval of normal pumping and when the current significantly deviates, the control circuit stops the pumping and gives a signal and an information on the display.  
   
   
       7 . The membrane pump according to  claim 6 , wherein the control circuit is programmable with a dosage of the transporting and with pump work time, intervals.  
   
   
       8 . The membrane pump according to  claim 7 , wherein the box is provided with a bar code reader and the control circuit being programmed for medicines and dosages, safeguarding that right data are programmed into the pump.  
   
   
       9 . The membrane pump according to  claim 8 , wherein the box is provided with loadable batteries driving the controls and the electric motor.  
   
   
       10 . The membrane pump according to  claim 1 , wherein the inlet check valve has a cone, which is indented with, a cut, 0.1 to 0.5 mm deep, in the upper part so that the valve is pervious when gaseous fluid occurs, but tight when liquid fluid occurs.  
   
   
       11 . The membrane pump according to  claim 1 , wherein the inlet check valve has a colored valve cone and that said inlet check valve is provided with a transparent housing, so that said colored valve cone is easy to observe.  
   
   
       12 . The membrane pump according to  claim 10 , wherein said cone of the inlet check valve has minor lugs, which affect the cone to move precisely in said transparent housing and that said cone has a lower density than the fluid pumped for effectively de-air liquid containing air or other gases.  
   
   
       13 . The membrane pump according to  claim 10 , wherein said cone is made to float on said fluid, whereby the cone and the fluid presses air back through a seat face of the inlet valve, if air is present in the fluid.