Blood suction apparatus

Claim 1

IN A BLOOD SUCTION APPARATUS, THE COMBINATION OF (A) A SOURCE OF VACUUM HAVING MEANS TENDING TO MAINTAIN THE VACUUM AT A SUBSTANTIALLY CONSTANT VALUE, (B) A PLURALITY OF SUCTION TIPS FOR IMMENSION IN POOLS OF BLOOD, (C) MEANS CONNECTING SAID SUCTION TIPS WITH SAID SOURCE SO THAT VACUUM IS AVAILABLE AT SAID SUCTION TIPS FOR DRAWING BLOOD INTO THE LATTER, AND (D) PRESSURE RESPONSIVE FLOW METERING MEANS INTERPOSED IN SAID CONNECTING MEANS BETWEEN EACH OF SAID SUCTIONTIPS AND SAID SOURCE OF VACUUM, EACH OF SAID FLOW METERING MEANS INCLUDING A VALVE BODY HAVING A CAVITY THEREIN WITH PORTS COMMUNICTING WITH SAID SOURCE OF VACUUM AND THE RELATED SUCTION TIP, RESPECTIVELY, A VALVE SPOOL MOVED IN SAID CAVITY BY DIFFERENTIAL PRESSURES ACTING THEREON THROUGH SAID PORTS BETWEEN A FIRST POSITION OCCUPIED BY SAID VALVE SPOOL WHEN THE RELATED SUCTION TIP IS IMMERSED IN BLOOD AND A SECOND POSITION OCCUPIED BY SAID VALVE SPOOL WHEN THE RELATED SUCTION TIP IS SUBSTANTIALLY OPEN TO THE ATMOSPHERE, AND COOPERATIVE MEANS IN SAID VALVE BODY AND SPOOL DEFINING A PASSAGE OF RELATIVELY LARGE CROSS-SECTION BETWEEN SAID PORTS WHEN SAID SPOOL IS IN SAID FIRST POSITION AND DEFINING A RESTRICTED PASSAGE BETWEEN SAID PORTS WHEN THE SPOOL IS IN SAID SECOND POSITION, THEREBY TO PERMIT A RELATIVELY HIGH RATE OF FLOW INTO THE RELATED SUCTION TIP WHEN THE LATTER IS IMMERSED IN BLOOD AND TO SUBSTANTIALLY RESTRICT THE RATE OF FLOW INTO SAID RELATED SUCTION TIP WHEN THE LATTER IS OPEN TO THE ATMOSPHERE, FOR AVOIDING SUBSTANTIAL LOSS OF VACUUM AT SAID SOURCE AND THE DRAWING IN OF LARGE VOLUMES OF AIR WITH BLOOD INTO SAID SUCTION TIPS.