Programmable logic controller-based system and user interface for air sampling in controlled environments

Patent metadata

Field	Value
Publication number	US-9939416-B2
Application number	US-201414471848-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Aug 28, 2014
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A system and method for sampling air at multiple locations in a controlled environment. The system and method includes automatic adjustment of mass flow rates and duration of vacuum connections (either via time elapsed or indirectly by volume) based on rates set by an operator. Additionally, the system and method enables users to monitor and control aspects of the system via network-connected devices. Additionally, the system enable a vacuum pump to be disconnected from power in response to a physical emergency button, a software-based emergency stop button available on network connected devices, and an automatic power disconnection in response to an abnormal mass flow reading that could potentially impact the vacuum pump.

First claim

What is claimed is:

1. A system for sampling air at multiple locations in a controlled environment comprising:
a plurality of air sampling devices configured to monitor and test a volume of air within a controlled environment;
a plurality of vacuum connections, each of the plurality of vacuum connections configured to receive the volume of air from one of the plurality of air sampling devices;
a plurality of flow control valves, each of the plurality of flow control valves configured to control a mass flow rate of the volume of air received by one of the vacuum connections;
a plurality of actuators, each of the plurality of actuators configured to open and close one of the flow control valves;
a plurality of flow sensors, each of the plurality of flow sensors configured to sense the mass flow rate of the volume of air received by one of the vacuum connections;
a flow center including a programmable logic controller (PLC) configured to:
receive setpoints indicative of desired mass flow rates at each of the air sampling devices;
receive measured flow rates from the plurality of flow sensors indicative of the mass flow rates of each of the vacuum connections;
determine errors indicative of the differences between the measured flow rates and the setpoints;
output control signals to the plurality of actuators to reduce the differences between the measured flow rates and the setpoints; and

an operator interface terminal including a graphical user interface (GUI) for receiving one or more setpoints indicative of a desired mass flow rate at one of the air sampling devices.

2. The system of claim 1 , wherein:
the plurality of air sampling devices comprises a first air sampling device and a second air sampling device;
the plurality of vacuum connections comprises a first vacuum connection configured to receive the volume of air from the first air sampling device and a second vacuum connection configured to receive the volume of air from the second air sampling device, the first and second vacuum connections in flow communication with a vacuum pump via a manifold;
the PLC is configured to reduce the difference between the measured flow rate of the volume of air received by the first vacuum connection and the setpoint indicative of the desired mass flow rate at the first air sampling device caused by a change in the volume of air through the second vacuum connection.

3. The system of claim 1 , wherein the each of the flow control valves are configured to adjust such that a change in position of the flow control valve is proportional to the size of the difference between the set point and the measured flow rate of the vacuum connection corresponding to the respective flow control valve.

4. The system of claim 1 , wherein the each of the flow control valves are configured to adjust such that a rate of change in position of the flow control valve is proportional to a rate of change of the difference between the set point and the measured flow rate of the vacuum connection corresponding to the respective flow control valve.

5. The system of claim 1 , wherein the system is configured to output data indicative of the mass flow rates of the volumes of air received by the plurality of vacuum connections to an external device via a network connection.

6. The system of claim 5 , wherein the external device is a supervisory control and data acquisition system or data collection system.

7. The system of claim 5 , wherein the network connection includes communication via the internet and the external device receives the data via a web browser or remote desktop application.

8. The system of claim 1 , wherein the system is configured to control the mass flow rates of the volume of air received by one of the plurality of vacuum connections based on a setpoint received from an external device.

9. The system of claim 1 , control the mass flow rates of the volume of air received by one of the plurality of vacuum connections based on a setpoint received from a web browser or remote desktop application via the internet.

10. The system of claim 1 , wherein each of the plurality of vacuum connections is in flow communication with a vacuum pump via a manifold, the vacuum pump is configured to draw the volume of air from the plurality of air sampling devices.

11. The system of claim 10 , wherein the vacuum pump further comprises a contactor configured to deliver and control power to the vacuum pump, the contactor comprising an emergency stop button configured to disconnect the power to the vacuum pump.

12. The system of claim 10 , wherein the graphical user interface comprises an emergency stop button configured to disconnect power to the vacuum pump.

13. The system of claim 10 , wherein the system is configured to disconnect power to the vacuum pump in response to a determination that the mass flow rate of the volume of air received by one of the vacuum connections in flow communication to the vacuum pump is below a predetermined threshold.

14. The system of claim 1 , wherein the operator interface terminal is co-located with the flow center.

15. The system of claim 1 , wherein the operator interface terminal is co-located with one of the plurality of air sampling devices.

16. A method for sampling air at multiple locations in a controlled environment, the method comprising:
monitoring and testing, by a plurality of air sampling devices, volumes of air within a controlled environment;
receiving, by a plurality of vacuum connections, the volumes of air from each of the plurality of air sampling devices;
controlling, by a plurality of flow control valves, mass flow rates of the volumes of air received by each of the vacuum connections;
sensing, by a plurality of flow sensors, the mass flow rates of the volumes of air received by each of the vacuum connections;
monitoring, the mass flow rates of air received by each of the plurality of vacuum connections;
outputting, to an operator interface terminal including a graphical user interface (GUI), data indicative of the mass flow rates of air received by each of the plurality of vacuum connections;
receiving, by a graphical user interface (GUI) of an operator interface terminal via the GUI, a setpoint indicative of a desired mass flow rate at one of the air sampling devices;
receiving, by a flow center including a programmable logic controller (PLC), setpoints indicative of desired mass flow rates at each of the air sampling devices;
receiving, by the PLC, measured flow rates from the plurality of flow sensors indicative of the mass flow rates of each of the vacuum connections;
determining, by the PLC, errors indicative of the differences between the measured flow rates and the setpoints; and
outputting, by the PLC, control signals to the plurality of flow control valves to reduce the differences between the measured flow rates and the setpoints.

17. The method of claim 16 , wherein the difference between the setpoint indicative of the desired mass flow rate at a first air sampling device and the measured flow rate of the volume of air received by a first vacuum connection receiving the volume of air from the first air sampling device is caused by a change in the volume of air through a second vacuum connection that is in flow communication with the first vacuum connection via a manifold.

18. The method of claim 16 , further comprising:
adjusting each of the flow control valves such that a change in position of the flow control valve is proportional to the size of the difference between the set point and the measured flow r

Assignees

• Veltek Ass Inc
• Veltek Assoicates Inc

Inventors

• Kocher Nathan G

Classifications

• G01N33/0073 Primary

  Control unit therefor · CPC title

• G01N33/0011 Primary

  Sample conditioning (preparing specimens for investigation G01N1/28) · CPC title

• G01N1/26

  with provision for intake from several spaces · CPC title

• G01N1/2273

  Atmospheric sampling · CPC title

• F24F2011/0005

  to create underpressure in a room, keeping contamination inside · CPC title