Pressure responsive switch, such as for water level control

Claim 1

IN COMBINATION: A RIGID ELECTRICALLY INSULATING CASING MADE OF AIR IMPREVIOUS MATERIAL AND HAVING A FIXED END WALL WITH A SMALL OPENING AND HAVING A DIAPHRAGM RECEIVING OPEN END; AN ELECTRICALLY INSULATING DIAPHRAGM, HAVING INNER AND OUTER SIDES, SEALED TO SAID CASING ADJACENT SAID OPEN END, AND HAVING A PLUNGER RECEIVING IRREGULARITY ON SAID INNER SIDE ALIGNED WITH SAID SMALL OPENING; A SWITCH IN SAID CASING HAVING AN ACTUATING SWITCH MEMBER MOVABLE TO A HIGH PRESSURE SWITCH POSITION AND TO A LOW PRESSURE SWITCH POSITION; MEANS FORMING A PRESSURE CHAMBER ADJACENT SAID OUTER SIDE OF SAID DIAPHRAGM; A SELF LUBRICATING AND ELECTRICALLY INSULATING PLUNGER WITH A LARGE INNER PORTION IN SAID CASING AND WITH A SMALL END OUTSIDE SAID CASING, SAID INNER PORTION BEING LOCKED BY SAID IRREGULARITY, SAID PLUNGER HAVING AN INTERMEDIATE PORTION ENGAGING SAID ACTUATING SWITCH MEMBER, SAID PLUNGER HAVING ITS SMALL END PASSING THROUGH SAND SNUGYL FITTING SAID SMALL OPENING TO FORM A SUBSTANTIALLY SEALED CUSHIONING CHAMBER ON SAID INNER SIDE OF SAID DIAPHRAGM; SPRING MEANS CARRIED BY SAID FIXED END WALL OUTSIDE SAID SMALL OPENING AND INWARDLY PRESSING SAID OUTER END OF SAID PLUNGER; AND ADJUSTABLE ACTUATING MEANS OUTSIDE SAID CUSHION CHAMBER ADJUSTING THE PRESSURE OF SAID SPRING ON SAID PLUNGER.