Medical Treatment System and Methods Using a Plurality of Fluid Lines

A system for measuring an amount of liquid in a pumping chamber of a pneumatically actuated diaphragm pump comprising:

• a fluid inlet and fluid outlet valve connected to the pumping chamber;
• a diaphragm separating a pneumatically actuated control chamber from the pumping chamber, the control chamber fluidly connected to a reference chamber of known volume via a conduit that includes a reference chamber valve;
• the control chamber fluidly connected via one or more actuation valves to a source of positive or negative pneumatic pressure;
• a controller configured to control the fluid inlet and outlet valves, the reference chamber valve, and the one or more actuation valves, and to receive pressure data from a first pressure sensor connected to the actuation chamber and a second pressure sensor connected to the reference chamber,
• wherein the controller is configured to isolate the pumping chamber by closing the fluid inlet and outlet valves, charge the control chamber with a first pneumatic pressure;
• vent the reference chamber or fix a pneumatic pressure in the reference chamber that is different from the control chamber pneumatic pressure;
• measure a first control chamber pressure and a first reference chamber pressure, connect the control chamber to the reference chamber by opening the reference chamber valve and equalizing pressures between the control chamber and the reference chamber, measure a third equalized pneumatic pressure in the control and reference chambers, and
• compute a control chamber volume based on an ideal gas model that assumes the presence of three closed mass systems of a gas comprising:
• a first mass system that occupies the control chamber at the end of pressure equalization;
• a second mass system that occupies the reference chamber before pressure equalization;
• and
• a third mass system that occupies the conduit, a part of the control chamber and a part of the reference chamber after equalization of pressure begins between the control and reference chambers.

A system for measuring an amount of liquid in a pumping chamber of a pneumatically actuated diaphragm pump comprising:

• a fluid inlet and fluid outlet valve connected to the pumping chamber;
• a diaphragm separating a pneumatically actuated control chamber from the pumping chamber, the control chamber fluidly connected to a reference chamber of known volume via a conduit that includes a reference chamber valve;
• the control chamber fluidly connected via one or more actuation valves to a source of positive or negative pneumatic pressure;
• a controller configured to control the fluid inlet and outlet valves, the reference chamber valve, and the one or more actuation valves, and to receive pressure data from a first pressure sensor connected to the actuation chamber and a second pressure sensor connected to the reference chamber;
• wherein the controller is configured to isolate the pumping chamber by closing the fluid inlet and outlet valves, charge the control chamber with a first pneumatic pressure;
• vent the reference chamber or fix a pneumatic pressure in the reference chamber that is different from the control chamber pneumatic pressure;
• measure a first control chamber pressure and a first reference chamber pressure, connect the control chamber to the reference chamber by opening the reference chamber valve and equalizing pressures between the control chamber and the reference chamber, measure a third equalized pneumatic pressure in the control and reference chambers, and
• compute the control chamber volume based on an ideal gas model that assumes the presence of three closed mass systems of a gas comprising:
• a first mass system that occupies the control chamber before pressure equalization;
• a second mass system that occupies the reference chamber at the end of pressure equalization;
• and
• a third mass system that occupies the conduit, a part of the control chamber and a part of the reference chamber after equalization of pressure begins between the control and reference chambers.

A system for measuring an amount of liquid in a pumping chamber of a pneumatically actuated diaphragm pump comprising:

• a fluid inlet and fluid outlet valve connected to the pumping chamber;
• a diaphragm separating a pneumatically actuated control chamber from the pumping chamber, the control chamber fluidly connected to a reference chamber of known volume via a conduit that includes a reference chamber valve;
• the control chamber fluidly connected via one or more actuation valves to a source of positive or negative pneumatic pressure;
• a controller configured to control the fluid inlet and outlet valves, the reference chamber valve, and the one or more actuation valves, and to receive pressure data from a first pressure sensor connected to the actuation chamber and a second pressure sensor connected to the reference chamber;
• wherein the controller is configured to isolate the pumping chamber by closing the fluid inlet and outlet valves, charge the control chamber with a first pneumatic pressure;
• vent the reference chamber or fix a pneumatic pressure in the reference chamber that is different from the control chamber pneumatic pressure;
• measure a first control chamber pressure and a first reference chamber pressure, connect the control chamber to the reference chamber by opening the reference chamber valve and equalizing pressures between the control chamber and the reference chamber, measure a third equalized pneumatic pressure in the control and reference chambers, and
• compute a control chamber volume based on an ideal gas model under a polytropic process, wherein the controller is configured to select a polytropic coefficient for the model using a pre-determined function in which the value of the polytropic coefficient depends on and varies with the control chamber volume.

A system for calculating a change in fluid volume in a pumping chamber of a pneumatically actuated diaphragm pump using a gas having a heat capacity ratio of n, the system comprising:

• a control chamber separated from the pumping chamber by a flexible diaphragm;
• a fluid inlet or outlet of the pumping chamber;
• a valve connecting the control chamber to a pressurized source of the gas;
• a pressure sensor fluidly connected to the control chamber,
• a controller that receives pressure data from the pressure sensor, that controls the valve, and that is configured to regulate pressure in the control chamber by opening or closing the valve;
• wherein the controller is configured to compute a change in volume of the control chamber as fluid enters or leaves the pumping chamber by monitoring a pressure change in the control chamber when the valve is closed;
• said computation assigning a first chamber volume to a first measured pressure, and calculating a second chamber volume based on a second later measured pressure using an equation in which a ratio of the second measured pressure to the first measured pressure is assumed to be equal to a ratio of the first chamber volume to the second chamber volume, raised to a power between 1 and n.