Mass flow ratio system and method

• US 6,766,260 B2
• Filed: 01/04/2002
• Issued: 07/20/2004
• Est. Priority Date: 01/04/2002
• Status: Expired due to Term

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Kottenstette, Nicholas E., Shajii, Ali, Ambrosina, Jesse
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Lau, Tung S
• Application Number:
  US10/037,882
• Publication Number:
  US 20030130807A1
• Time in Patent Office: 928 Days
• Field of Search: 702/45, 607/81, 137/487, 137/118, 137/875, 137/88, 731/97, 738/61, 141/8, 141/66, 141/7, 700/277, 406/14, 432/198, 118/715, 438/710, 422/111
• US Class Current: 702/45
• CPC Class Codes: G01F 1/68 by using thermal effects
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: Y10T 137/0363 For producing proportionate flow
• CPC Class Codes: Y10T 137/2529 With electrical controller
• CPC Class Codes: Y10T 137/2657 Flow rate responsive
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/87877 Single inlet with multiple distinctly valved outlets

Abstract

A system for dividing a single mass flow, including an inlet adapted to receive the single mass flow and at least two flow lines connected to the inlet. Each flow line includes a flow meter and a valve. The system also includes a controller programmed to receive a desired ratio of flow through a user interface, receive signals indicative of measured flow from the flow meters, calculate an actual ratio of flow through the flow lines based upon the measured flows, and compare the actual ratio to the desired ratio. The controller is also programmed to calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and provide a signal indicative of the desired flow to at least one of the valves.

Claims

1. A system for dividing a single mass flow into two or mare secondary flows of desired ratios, comprising:

A) an inlet adapted to receive the single mass flow;

B) at least two secondary flow lines connected to the inlet, each flow line including,

a flow meter measuring flow through the flow line and providing a signal indicative of the measured flow, and

a valve controlling flow through the flow line based upon a signal indicative of desired flow rate;

C) a user interface adapted ta receive at least one desired ratio of flow; and

D) a controller connected to the flow meters, the valves, and the user interface, and programmed to,

receive the desired ratio of flow through the user interface,

receive the signals indicative of measured flow from the flow meters,

calculate an actual ratio of flow through the flow lines based upon the measured flow,

compare the actual ratio to the desired ratio,

calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and

provide a signal indicative of the desired flow to at least one of the valves, wherein the desired flow is substantially equal to K_p(α

−

α

_sp)+K_i∫

(α

−

α

_sp)_dt, wherein K_p is a proportional gain, K_i is an integral gain, α

is the actual flow ratio, and α

_sp is the desired flow ratio.

2. A system for dividing a single mass flow into two or more secondary flows of desired ratios, comprising:

A) an inlet adapted to receive the single mass flow;

B) at least two secondary flow lines connected to the inlet, each flow line including,

a flow meter measuring flow through the flow line and providing a signal indicative of the measured flow, and

a valve controlling flow through the flow line based upon a signal indicative of desired flow rate;

C) a user interface adapted to receive at least one desired ratio of flow; and

D) a controller connected to the flow meters, the valves, and the user interface, and programmed to,

receive the desired ratio of flow through the user interface,

receive the signals indicative of measured flow from the flow meters,

calculate an actual ratio of flow through the flow lines based upon the measured flow,

compare the actual ratio to the desired ratio,

calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and

provide a signal indicative of the desired flow to at least one of the valves, wherein the desired flow is substantially equal to K_p(α

−

α

_sp)+K_i∫

(α

−

α

_sp)_dt; and

E) a pressure sensor measuring pressure in the inlet and connected to the controller to provide the pressure measurement to the controller, wherein the controller is programmed to provide a signal indicative of the desired flow to the valve of the first flow line substantially equal to K_pα

(α

−

α

_sp)+K_iα

∫

(α

−

α

_sp)_dt, wherein K_p is a proportional gain for ratio control, K_i is an integral gain for ratio control, α

is the actual flow ratio, and α

_sp is the desired flow ratio.

3. A system for dividing a single mass flow into two or more secondary flows of desired ratios, comprising:

A) an inlet adapted to receive the single mass flow;

B) at least two secondary flow lines connected to the inlet, each flow line including,

a flow meter measuring flow through the flow line and providing a signal indicative of the measured flow, and

a valve controlling flow through the how hue based upon a signal indicative of desired flow rate;

C) a user interface adapted to receive at least one desired ratio of flow; and

D) a controller connected to the flow meters, the valves, and the user interface, and programmed to,

receive the desired ratio of flow through the user interface,

receive the signals indicative of measured flow from the flow meters,

calculate an actual ratio of flow through the flow lines based upon the measured flow,

compare the actual ratio to the desired ratio,

calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and

provide a signal indicative of the desired flow to at least one of the valves, wherein the desired flow is substantially equal to K_p(α

−

α

_sp)+K_i∫

(α

−

α

_sp)_dt; and

E) a pressure sensor measuring pressure in the inlet and connected to the controller to provide the pressure measurement to the controller, wherein the controller is programmed to provide a signal indicative of the desired flow to the valve of the second flow line substantially equal to K_p(P_in−

P_t)+K_i(P_in−

P_i)_dt, wherein K_p is a proportional gain for pressure control, K_i is an integral gain for pressure control, P_in is the measured inlet pressure, and P₁ is an operating pressure threshold.

4. A method for dividing a single mass flow into two or more secondary mass flows of desired ratios, comprising:

A) dividing a single mass flow into at least two flow lines;

B) measuring mass flow through each flow line;

C) receiving at least one desired ratio of mass flow;

D) calculating an actual ratio of mass flow through the flow lines based upon the measured flows;

E) calculating a desired flow through at least one of the flow lines if the actual ratio does not equal the desired ratio; and

F) regulating the flow line to the desired flow, wherein the desired flow is substantially equal to K_p(α

−

α

_sp)+K_i∫

(α

−

α

_sp)_dt, wherein K_p is a proportional gain, K_i is an integral gain, α

is the actual flow ratio, and α

_sp is the desired flow ratio.

5. A method for dividing a single mass flow into two or more secondary mass flows of desired ratios:

comprising;

A) dividing a single mass flow into at least two flow lines;

B) measuring mass flow through each flow line;

C) receiving at least one desired ratio of mass flow;

D) calculating an actual ratio of mass flow through the flow lines based upon the measured flows;

E) calculating a desired flow through at least one of the flow lines if the actual ratio does not equal the desired ratio;

F) regulating the flow line to the desired flow; and

G) measuring pressure in the inlet, wherein the desired flow in one of the flow lines is substantially equal to K_pα

(α

−

α

_sp)+K_iα

∫

(α

−

α

_sp)_dt, wherein K_p is a proportional gain for ratio control, K_i is an integral gain for ratio control, α

is the actual flow ratio, and α

_sp is the desired flow ratio.

6. A method for dividing a single mass flow into flow or more secondary mass flows of desired ratios, comprising:

A) dividing a single mass flow into at least two flow lines;

B) measuring mass flow through each flow line;

C) receiving at least one desired ratio of mass flow;

D) calculating an actual ratio of mass flow through the flow lines based upon the measured flows;

E) calculating a desired flow through at least one of the flow lines if the actual ratio does not equal the desired ratio;

F) regulating the flow line to the desired flow; and

G) measuring pressure in the inlet, wherein the desired flow in one of the flow lines is substantially equal to K_p(P_in−

P₁)+K_i∫

(P_in−

P₁)_dt, wherein K_p is a proportional gain for pressure control, K_i is an integral gain for pressure control, P_in is the measured inlet pressure, and P₁ is an operating pressure threshold.