Apparatus for controlling a mass flow rate of liquid in a chemical process

Claim 2

In an apparatus for controlling the mass flow rate of a liquid in a chemical process, an improvement comprising a liquid measuring device, means defining input and output liquid passages connected to said measuring device, first automatic control means for controlling the flow rate of liquid through one of said input and output passages in response to an actuating first signal, second automatic control means for automatically controlling the flow rate of liquid in the other of said input and output passages in response to an actuating second signal, calculating means connected to said measuring device for calculating an average mass flow rate of liquid from a weight difference of liquid within said measuring device during a time interval and having output means for producing a third signal indicative of said average mass flow rate, comparator means having said third signal output means connected thereto and having input means for receiving a reference signal indicative of a reference mass flow rate and including means for detecting a deviation between said third signal and said reference signal and providing a corresponding output signal comprising said actuating second signal and applying same to said second control means to accordingly control the average mass flow rate of liquid, and programmer means having input means connected to said measuring device for generating said actuating first signal and for generating output signals and applyIng same to both said calculating and comparator means for actuating said first automatic control means, calculating means, and comparator means in accordance with a predetermined program.

Claim 3

An improved apparatus for controlling a mass flow rate of liquid according to claim 1, wherein said measuring device comprises a container having said input and output passages connected thereto, and a weighing mechanism supporting said container and including means for generating signals indicative of said weight difference of liquid.

Claim 4

An improved apparatus for controlling a mass flow rate of liquid according to claim 2, wherein said means for calculating an average mass flow rate of liquid comprises measuring means connected to said weighing mechanism for measuring net weights of liquid contained in said container together with net weight of said container at suitable intervened times, an arithmetic unit for automatically calculating a value of an average mass flow rate (weight difference between two measured weights obtained by said measuring means) / (time interval between weighing instants).

Claim 5

An improved apparatus for controlling a mass flow rate of liquid according to claim 3, wherein said container is encased in an outside container which is sealed to satisfy set conditions of operating temperature and pressure, said measuring means for measuring net weight of liquid together with net weight of said container is disposed in said outside container, and said arithmetic unit is disposed outside of said outside container for receiving an output signal of said measuring means.

Claim 6

An improved apparatus for controlling a mass flow rate of liquid according to claim 2, wherein said means for calculating an average mass flow rate of liquid comprises means for measuring a time interval corresponding to a predetermined weight difference of liquid contained in said container measured by said weighing mechanism at two different measuring instants, and an arithmetic unit for automatically calculating a value of an average flow rate (said weight difference) / (output of said means for measuring a time interval).

Claim 7

An improved apparatus for controlling a mass flow rate of liquid according to claim 2, wherein said means for calculating an average mass flow rate of liquid comprises measuring means connected to said weighing mechanism for measuring net weights of liquid contained in said container together with net weight of said container at predetermined intervened times, and an arithmetic unit for automatically calculating a value of an average mass flow rate (weight difference between two measured weights obtained by said measuring means) / (said predetermined time interval).

Claim 8

An improved apparatus for controlling a mass flow rate of liquid according to claim 6, wherein said container is encased in an outside container which is sealed to satisfy set conditions of operating temperature and pressure, said measuring means for measuring net weight of liquid together with net weight of said container is disposed outside of said outside container, and said arithmetic unit is disposed outside of said outside container for receiving an output signal of said measuring device.

Claim 9

An improved apparatus for controlling a mass flow rate of liquid according to claim 1, wherein said measuring device comprises an inside container, an outside contained encasing said inside container, and a weighing mechanism supporting said inside container in said outside container, said input passage comprises a supply conduit passing through a wall of said outside container and connected to said inside container, and said output passage comprises a discharging conduit passing through a wall of said outside container and connected to a bottom portion of said inside container.

Claim 10

An improved apparatus for controlling a mass flow rate of liquid according to claim 1, wherein said measuring device comprises a liquid container having a sealed gas phase portion and said otheR passage means comprises a first connecting conduit means for connecting said sealed gas phase portion of said liquid container with an air pressure source disposed outside of said liquid container, and a second conduit means for connecting said gas phase portion of said liquid container with atmosphere, and wherein said second automatic control means includes a first pressure control actuator mounted on said first connecting conduit means and a second pressure control actuator on said second conduit means, said first pressure control actuator and said second pressure control actuator are connected to said signal output means of said comparator means for being actuated alternatively in accordance with said actuating second signal.

Claim 11

In an apparatus for controlling the mass flow rate of a liquid in a chemical process, an improvement comprising a liquid measuring device, means defining input and output liquid passages connected to said measuring device, first automatic control means for controlling the flow rate of liquid through one of said input and output passages in response to an actuating first signal, second automatic control means for automatically controlling the instantaneous flow rate of liquid in the other of said input and output passages and including means for selectively compensating for instantaneous fluctuations in the liquid flow rate in the other of said passages, calculating means connected to said measuring device for calculating the average mass flow rate of liquid from a weight difference of liquid within said measuring device during a time interval and having output means for producing a second signal indicative of said average mass flow rate, comparator means having said second signal output means connected thereto and having input means for receiving a reference signal indicative of a reference mass flow rate and having means for detecting a deviation between said second signal and said reference signal and providing a corresponding actuating third signal and applying same to said second automatic control means for actuating said second control means to control the instantaneous mass flow rate of liquid, and programmer means having input means connected to said measuring device for generating said actuating first signal and for generating output signals and applying same to both said calculating and comparator means for actuating said first automatic control means, calculating means and comparator means in accordance with a predetermined program.

Claim 12

In an apparatus for controlling the mass flow rate of a liquid in a chemical process, an improvement comprising a liquid measuring device, means defining input and output liquid passages connected to said measuring device, first automatic control means for controlling the flow rate of liquid through one of said input and output passages in response to an actuating first signal, second automatic control means for automatically controlling the instantaneous flow rate of liquid in the other of said input and output passages and including means for selectively compensating for instantaneous fluctuations in the liquid flow rate in the other of said passages, calculating means connected to said measuring device for calculating the average mass flow rate of liquid from a weight difference of liquid within said measuring device during a time interval and having output means for producing a second signal indicative of said average mass flow rate, comparator means having said second signal output means connected thereto and having input means for receiving a reference signal indicative of a reference mass flow rate and having means for detecting a deviation between said second signal and said reference signal and providing a corresponding actuating third signal and applying same to said second automatic control means for actuating said second control means to control the instantaneous mass flow rate of liquid, and programmer means having input means connected to said measuring device for generating said actuating first signal and for generating output signals and applying same to both said calculating and comparator means for actuating said first automatic control means, calculating means and comparator means in accordance with a predetermined program.

Claim 13

An improved apparatus for controlling a mass flow rate of liquid according to claim 10, wherein said measuring device comprises a liquid container having a sealed gas phase portion and connected to said input liquid passage for receiving therefrom the liquid and connected to said output liquid passage for delivering thereto the liquid from said liquid container, and wherein said second automatic control means includes first means for alternatively supplying and exhausting a pressurized gas to and from the interior of said sealed gas phase portion in accordance with a control signal to accordingly pressurized the liquid contained within said liquid container, pressure sensing means for sensing the pressure of the pressurized gas within said sealed gas phase portion and providing a corresponding output signal, and second means responsive to said output signal for developing an appropriate control signal whenever said output signal is above or below a predetermined range of values and applying same to said first means to accordingly control the supplying and exhausting of pressurized gas to said sealed gas phase portion to thereby effectively control the liquid pressure, whereby instantaneous fluctuations in the mass flow rate of the liquid are compensated for by selectively controlling the liquid pressure.