Hydraulic system having boost pump in series with a primary pump and a boost pump drive therefor

An air seeder comprising:

• a wheeled frame adapted to be connected to a prime mover for movement over the ground at a ground speed and having a main source of hydraulic power including a main pump and a reservoir;
• a tank supported on said frame to retain a supply of material to be distributed to the ground during operation of said air seeder as said air seeder is being moved over the ground;
• a fan rotatably supported on said frame to create a flow of air;
• distribution means for distributing the material to the ground in a predetermined manner;
• conduit means operably associated with said tank to receive quantities of material therefrom, with said fan to receive a flow of air therefrom and entrain said quantities of material within said flow of air, and with said distribution means to deliver said quantities of material entrained within said flow of air thereto for distribution to the ground;
• a hydraulic motor operably connected to said fan selectively effecting rotation thereof to create said flow of air, said hydraulic motor having a high pressure supply line connected to an inlet of said hydraulic motor and a low pressure return line connected to an outlet of said hydraulic motor, said supply and return lines adapted to be connected to output and return ports respectively of said main source of hydraulic power for the circulation of hydraulic fluid through said hydraulic motor;
• a boost pump having an outlet and an inlet in communication with downstream and upstream portions of said high pressure supply line respectively, such that said boost pump is in series with said main pump whereby the boost pump serves to boost the pressure of the flow of hydraulic fluid delivered to said hydraulic motor;
• a drive for said boost pump;
• and
• a fluid control means disposed between the outlet of said boost pump and the inlet of said hydraulic motor to assist in controlling the speed of said hydraulic motor.

In an air seeder having a wheeled frame adapted to be connected to a prime mover for movement over the ground at a ground speed and including a main source of hydraulic power including a main pump and a reservoir;

• a tank supported on said frame to retain a supply of material to be distributed to the ground during operation of said air seeder as said air seeder is being moved over the ground;
• a fan rotatably supported on said frame to create a flow of air;
• distribution means for distributing the material to the ground in a predetermined manner;
• conduit means receiving said flow of air from said fan and interconnecting said tank, to receive quantities of material therefrom and entrain said quantities of material within said flow of air, and said distribution means to deliver said quantities of material entrained within said flow of air thereto for distribution to the ground;
• and a hydraulic motor operably connected to said fan for selectively effecting rotation thereof to create said flow of air, said hydraulic motor having a high pressure supply line connected to an inlet of said hydraulic motor and a low pressure return line connected to an outlet of said hydraulic motor, said supply and return lines adapted to be connected to output and return ports respectively of said main source of hydraulic power for the circulation of hydraulic fluid through said hydraulic motor, the improvement comprising:
• a boost pump having an outlet and an inlet in communication with downstream and upstream portions of said high pressure supply line respectively, such that said boost pump is in series with said main pump whereby the boost pump serves to boost the pressure of the flow of hydraulic fluid delivered to said hydraulic motor, said boost pump having a drive mechanism including a first ground engaging wheel supported by said agricultural implement and being connected via a mechanical drive train to said boost pump so that said boost pump is driven at speeds dependent on a ground speed of the agricultural machine.