Using two or more pressure regulators in series as a flow regulator

A flow control device for a fluid flow network, comprising:

• an upstream pressure regulator that is set to have a first constant pressure at an outlet port of the upstream pressure regulator, the first constant pressure being set to a value that is below a minimum upstream pressure delivered from an upstream portion of the fluid flow network to an inlet port of the upstream pressure regulator;
• and
• a downstream pressure regulator that is set to have a second constant pressure at the outlet port of the downstream pressure regulator, the second constant pressure being set to maintain a constant pressure differential across the downstream pressure regulator,
• wherein the upstream pressure regulator is coupled to the downstream pressure regulator at an identified location in the fluid flow network to set a flow rate of a fluid to be a constant level,
• wherein the inlet port of the flow control device is connected to an upstream portion of the fluid flow network at the identified location,
• wherein the outlet port of the flow control device is connected to a downstream portion of the fluid flow network at the identified location,
• wherein the flow rate at the identified location is maintained at the constant value based on the minimum upstream pressure to the flow control device exceeding the first constant pressure and further based on the constant pressure differential maintained across the downstream pressure regulator;
• and
• wherein the upstream pressure regulator and the downstream pressure regulator are connected to each other in series with respect to the upstream portion and the downstream portion of the fluid flow network.

A fluid flow system comprising:

• an upstream portion of a fluid flow network;
• a downstream portion of the fluid flow network;
• and
• a flow control device disposed at an identified location of the fluid flow network, comprising:
• an upstream pressure regulator that is set to have a first constant pressure at an outlet port of the upstream pressure regulator, the first constant pressure being set to a value that is below a minimum upstream pressure delivered from the upstream portion of the fluid flow network to an inlet port of the upstream pressure regulator;
• and
• a downstream pressure regulator that is set to have a second constant pressure at the outlet port of the downstream pressure regulator, the second constant pressure being set to maintain a constant pressure differential across the downstream pressure regulator,
• wherein the upstream pressure regulator is coupled to the downstream pressure regulator at the identified location in the fluid flow network to set a flow rate of a fluid to be a constant level,
• wherein the inlet port of the flow control device is connected to the upstream portion of the fluid flow network at the identified location,
• wherein the outlet port of the flow control device is connected to the downstream portion of the fluid flow network at the identified location,
• wherein the flow rate at the identified location is maintained at the constant value based on the minimum upstream pressure to the flow control device exceeding the first constant pressure and further based on the constant pressure differential maintained across the downstream pressure regulator;
• and
• wherein the upstream pressure regulator and the downstream pressure regulator are connected to each other in series with respect to the upstream portion and the downstream portion of the fluid flow network.