Fluid ejection and circulation

A fluid ejection and circulation apparatus may include a fluid ejection device, a filter to filter fluid supplied to the fluid ejection device and a pressure regulator. The pressure regulator may include a fluid chamber having a fluid port and a first port extending from the fluid chamber to the filter. The pressure regulator may further include a valve to open and close the fluid port and a compliant chamber within the fluid chamber. The compliant chamber is to undergo different inflation levels in response to fluid chamber pressure. The valve is to open and close the fluid port in response to changes in an inflation level of the compliant chamber. The fluid chamber comprises a second port cooperating with the first port to form a circulation path through the fluid chamber that is directed away from the filter.