Pump and valve assembly

Claim 1

A PUMP FOR PUMPING AGGREGATE-CONTAINING CONCRETE COMPRISING: A FIRST DELIVERY PISTON RECIPROCALLY MOUNTED IN A FIRST CYLINDER, SAID FIRST DELIVERY PISTON HAVING AN UPSTREAM FACE AND A DOWNSTREAM FACE; A SECOND DELIVERY PISTON RECIPROCALLY MOUNTED IN A SECOND CYLINDER, SAID SECOND DELIVERY PISTON HAVING AN UPSTREAM FACE AND A DOWNSTREAM FACE; A CONCRETE-SUPPLY HOPPER IN FLUID COMMUNICATION WITH EACH OF SAID CYLINDERS; A FIRST CONCRETE-DELIVERY LINE HAVING AN UPSTREAM END IN FLUID COMMUNICATION WITH SAID FIRST CYLINDER AND A DOWNSTREAM END; A SECOND CONCRETE-DELIVERY LINE HAVING AN UPSTREAM END IN FLUID COMMUNICATION WITH SAID SECOND CYLINDER AND A DOWNSTREAM END; A COMMON CONCRETE-DELIVERY MANIFOLD IN FLUID COMMUNICATION WITH SAID DOWNSTREAM ENDS OF SAID FIRST AND SECOND DELIVERY LINES; A FIRST VALVE CONTROLLING FLOW OF MATERIALS FROM SAID HOPPER TO SAID FIRST CYLINDER; A SECOND VALVE CONTROLLING FLOW OF MATERIAL FROM SAID HOPPER TO SAID SECOND CYLINDER; A THIRD VALVE CONTROLLING FLOW OF MATERIAL THROUGH SAID FIRST DELIVERY LINE; A FOURTH VALVE CONTROLLING FLOW OF MATERIAL THROUGH SAID SECOND DELIVERY LINE; A VALVE-ACTUATING PISTON CONNECTED TO EACH OF SAID VALVES FOR CONTROLLING THE OPERATION THEREOF, EACH OF SAID VALVE-ACTUATING PISTONS HAVING AN UPSTREAM FACE AND A DOWNSTREAM FACE; A FIRST TRANSFER VALVE MEANS FOR SELECTIVELY PLACING SAID UPSTREAM FACES OF SAID VALVE-ACTUATING PISTONS IN FLUID COMMUNICATION WITH A SOURCE OF HYDRAULIC FLUID UNDER PRESSURE AND WITH A RESERVOIR, AND FOR PLACING SAID DOWNSTREAM FACES OF SAID VALVE-ACTUATING PISTONS IN FLUID COMMUNICATION WITH SAID SOURCE OF HYDRAULIC FLUID UNDER PRESSURE AND WITH SAID RESERVOIR; A FIRST HYDRAULIC LINE PLACING THE DOWNSTREAM FACES OF SAID SECOND AND THIRD VALVES IN FLUID COMMUNICATION WITH SAID TRANSFER VALVE; A SECOND HYDRAULIC LINE PLACING THE DOWNSTREAM FACES OF SAID FIRST AND FOURTH VALVES IN HYDRAULIC COMMUNICATION WITH SAID TRANSFER VALVE; A THIRD HYDRAULIC LINE PLACING THE UPSTREAM FACES OF SAID FIRST AND FOURTH VALVES IN FLUID COMMUNICATION WITH SAID TRANSFER VALVE; A FOURTH HYDRAULIC LINE PLACING THE UPSTREAM FACES OF SAID SECOND AND THIRD VALVES IN FLUID COMMUNICATION WITH SAID TRANSFER VALVE; A FIRST SOLENOID CONNECTED TO SAID TRANSFER VALVE, ACTUATION OF SAID FIRST SOLENOID PLACING SAID FIRST AND THIRD HYDRAULIC LINES IN COMMUNICATION WITH SAID RESERVOIR; A SECOND SOLENOID CONNECTED TO SAID TRANSFER VALVE, ACTUATION OF SAID SECOND SOLENOID PLACING SAID FIRST AND THIRD HYDRAULIC FLUID UNDER PRESSURE; SAID SOURCE OF HYDRAULIC FLUID UNDER PRESSURE; A THIRD SOLENOID CONNECTED TO SAID TRANSFER VALVE, ACTUATION OF SAID THIRD SOLENOID PLACING SAID SECOND AND FOURTH HYDRAULIC LINES IN FLUID COMMUNICATION WITH SAID SOURCE OF HYDRAULIC FLUID UNDER PRESSURE; A FOURTH SOLENOID CONNECTED TO SAID TRANSFER VALVE, ACTUATION OF SAID FOURTH SOLENOID PLACING SAID SECOND AND FOURTH HYDRAULIC LINES IN FLUID COMMUNICATION WITH SAID RESERVOIR; A LATCHING RELAY CONNECTED TO SAID SOLENOIDS, SAID LATCHING RELAY HAVING A FIRST POSITION COMPLETING AN ELECTRICAL CIRCUIT TO SAID FIRST AND THIRD SOLENOIDS AND A SECOND POSITION COMPLETING A CIRCUIT TO SAID SECOND AND FOURTH SOLENOIDS; SAID LATCHING RELAY BEING MOVED TO SAID FIRST POSITION BY ENERGIZATION OF A FIRST COIL AND TO SAID SECOND POSITION BY ENERGIZATION OF A SECOND COIL; A FIRST LIMIT SWITCH CONNECTING SAID FIRST COIL TO SAID FIRST CYLINDER FOR ACTUATING BY SAID FIRST DELIVERY PISTON TO ENERGIZE SAID FIRST COIL; A SECOND LIMIT SWITCH CONNECTING SAID SECOND COIL TO SAID SECOND CYLINDER FOR ACTUATION BY SAID SECOND DELIVERY PISTON TO ACTUATE SAID SECOND COIL; AND MEANS FOR RECIPROCATING SAID DELIVERY PISTONS IN OPPOSITIOM TO EACH OTHER.