referring to the drawing , the control valve of the invention 10 includes a generally cylindrical housing 20 of metal , plastic or the like suitable for the purposes of the invention . the housing includes a piston 30 of metal or other suitable material slidably disposed therein . the housing includes a cap 40 at its upper end and a cap 60 at its lower end the upper cap is slidable up and down on the upper end of the housing . the piston carries , near its upper end , an assembly of plates 70 spaced apart by an o - ring 74 . this assembly slides inside the cylinder in gas - tight engagement with the inner wall of the housing cylinder . in the up position of the plunger , the the assembly of plates 70 engages the upper end wall of the cylinder as a stop . the upper cap is slidable on the housing . the piston also carries an assembly of plates 80 and o - ring 84 positioned as described below . the housing 20 carries the following tubes . an oxygen tube 100 is secured to the housing near the upper end thereof below the assembly of plates 70 ( when the plunger is up ) and this tube is connected to a source of oxygen at a wall mounting . beneath this tube is a patient tube 110 which extends by a catheter 120 to a patient . finally , a suction tube 130 is secured near the lower end of the housing beneath the patient tube and extends to a source of suction at the wall . the lower set of plates 80 is positioned just above the suction tube 130 when the plunger is up . as seen in the drawing , the piston is in the up position in which the tube 100 from wall oxygen has oxygen flow from the wall around the piston to the outlet 100 to the patient . at this time , the lower assembly of plates causes suction to flow to atmosphere through the slits in the lower cap . if the cap is pressed downwardly , the piston moves to the position in which the oxygen tube 100 is blocked by the plate assembly 70 and the outlet to the patient is open and the lower plates are beneath the suction line 130 as shown in dash lines . thus there can be flow of suction from the wall to the patient . according the invention , the outer wall of the piston is provided with an enlargement 150 which is called a throttle plate . this enlargement is of such size that when the plunger is down , the throttle plate lies in the path from the patient to the source of suction . the throttle plate does not block this path but throttles down the velocity of the flow of suction where surges are prevented . in operation of the valve 10 , when the piston is raised , oxygen flows from the wall into tube 190 and through the piston and out the tube to a patient . at this time , the assembly of plates 150 blocks a suction path and causes suction to flow to atmosphere through the slots in the bottom cap 170 . when the plunger is pushed down , the plate 150 lies below the suction line and the throttle lies across the opening in the tube and air flow from the wall suction source in the patient tube is reduced in velocity or intensity and controlled suction is achieved . this prevents suction surges and provide safety for the patient .
the disclosure is of a medical valve for handling oxygen and suction and including a suction flow path in which there is a means for throttling down the flow to a level at which there are no , possibly damaging , surges .