Clean room control system and method

1. In a clean room defining a plurality of compartments/zones and including an air handling system having a plurality of speed adjustable fans and a plurality of position controllable return air dampers, wherein the air handling system is operative for supplying pressurized air to the clean room, a method of controlling particulate count in the clean room comprising:

(a) controlling speeds of the plurality of fans and/or positions of the plurality of dampers whereupon air pressure in the clean room decreases compartment/zone-by-compartment/zone in series from a first compartment/zone which has a requirement for a lowest particulate count and hence a highest air pressure in the clean room to a last compartment/zone which has a requirement for a highest particulate count and hence a lowest air pressure in the clean room, wherein, in a direction from the first compartment/zone to the last compartment/zone, each compartment/zone in the series has a lower pressure than an immediately preceding compartment/zone;

(b) changing the speeds of the plurality of fans and/or the positions of the plurality of return air dampers in a manner that changes a volume of air per unit of time that moves through the clean room while maintaining the relationship that the first compartment/zone has the highest air pressure in the clean room, the last compartment/zone has the lowest air pressure in the clean room and, in the direction from the first compartment/zone to the last compartment/zone, each compartment/zone in the series has a lower pressure than an immediately preceding compartment/zone; and changing the speeds of the plurality of fans and/or the position of the plurality of return air dampers in response to determining a particle count of a compartment/zone exceeds a corresponding predetermined compartment/zone particle count.

2. The method of claim 1 , further including at least one of the following:

the air pressure of the first compartment/zone in step (b) is different than the air pressure of the first compartment/zone in step (a); and

the air pressure of the last compartment/zone in step (b) is different than the air pressure of the last compartment/zone in step (a).

3. The method of claim 1 , wherein the compartment/zone-to-compartment/zone decrease in air pressure in step (b) is the same or different than the compartment/zone-to-compartment/zone decrease in air pressure in step (a).

4. The method of claim 1 , wherein the change in step (b) either decreases or increases the volume of air per unit of time that moves through the clean room.

5. The method of claim 1 , wherein the change is step (b) occurs in a stepwise manner compartment/zone-to-compartment/zone in series from the first compartment/zone to the last compartment/zone, or vice versa, based on whether the volume of air that moves through the clean room per unit of time is being increased or decreased.

6. The method of claim 1 , wherein each particulate count is below a predetermined particulate count.

7. The method of claim 1 , further comprising changing the speeds of the plurality of fans and/or the positions of the plurality of return air dampers in response to determining the particle count of each compartment/zone no longer exceeds the corresponding predetermined compartment/zone particle count.

8. In a clean room having first, second and third compartments/zones in series, a method of controlling particulate count in the clean room comprising:

(a) in response to a first level of energy consumption by speed adjustable fans supplying a first volume of air per unit of time to the clean room, establishing differential air pressures in the clean room such that the first, second and third compartments/zones have highest, intermediate and lowest air pressures, respectively, in the clean room;

(b) in response to a second level of energy consumption by the speed adjustable fans supplying a second volume of air per unit of time to the clean room, maintaining substantially the same differential air pressures of step (a) in the clean room; and changing the speeds of the plurality of fans and/or the position of the plurality of return air dampers in response to determining a particle count of a compartment/zone exceeds a corresponding predetermined compartment/zone particle count.

9. The method of claim 8 , wherein the first volume of air per unit of time is greater than the second volume of air per unit of time.

10. The method of claim 9 , wherein the first level of energy consumption is greater than the second level of energy consumption, and the method further includes:

during transition from the first level of energy consumption to the second level of energy consumption, reducing a volume of air per unit of time supplied to the third compartment/zone first, reducing a volume of air per unit of time supplied to the first compartment/zone last, and reducing a volume of air per unit of time supplied to the second compartment/zone intermediate the reduction in the volumes of air per unit of time supplied to the third and first compartments/zones; and

during transition from the second level of energy consumption to the first level of energy consumption, increasing a volume of air per unit of time supplied to the first compartment/zone first, increasing a volume of air per unit of time supplied to the third compartment/zone last, and increasing a volume of air per unit of time supplied to the second compartment/zone intermediate the increase in the volumes of air per unit of time supplied to the first and third compartments/zones.

11. The method of claim 10 , further comprising transitioning from the second energy consumption state to the first energy consumption state in response to determining a particle count of a compartment/zone exceeds a corresponding predetermined compartment/zone particle count.

12. The method of claim 11 , further comprising transitioning from the first energy consumption state to the second energy consumption state in response to determining the particle count of each compartment/zone no longer exceeds the corresponding predetermined compartment/zone particle count.

13. A clean room control system comprising:

a plurality of speed adjustable fans operative for urging pressurized air into a number of compartments/zones of the clean room;

a plurality of position adjustable dampers disposed in air ducts that access the clean room; and

a controller operative for controlling the speeds of the fans and the positions of the dampers whereupon:

in a first energy consumption state of the fans to move a first volume of air per unit of time through the clean room, a differential air pressure is established in the clean room between a first compartment/zone and a second compartment/zone;

in a second energy consumption state of the fans to move a second, lesser volume of air per unit of time through the clean room, the differential air pressure is substantially maintained in the clean room between the first compartment/zone and the second compartment/zone; and changing the speeds of the plurality of fans and/or the position of the plurality of return air dampers in response to determining a particle count of a compartment/zone exceeds a corresponding predetermined compartment/zone particle count.

14. The clean room control system of claim 13 , wherein the first compartment/zone has a higher air pressure than the second compartment/zone.

15. The clean room control system of claim 13 , wherein the controller is further operative for controlling the speeds of the fans and the positions of the dampers whereupon:

during transition from the first energy consumption state to the second energy consumption state, the air pressure in the second compartment/zone is reduced before the air pressure in the first compartment/zone; and

during transition from the second energy consumption state to the first energy consumption state, the air pressure in the first compartment/zone is increased before the air pressure in the second compartment/zone.

16. The clean room control system of claim 15 , further comprising a plurality of particle sensors in communication with the controller, wherein the controller transitions from the second energy consumption state to the first energy consumption state at least partially in response to at least one of the plurality of particle sensors detecting a particle count of a compartment/zone exceeds a corresponding predetermined compartment/zone particle count.

17. The clean room control system of claim 16 , wherein the controller transitions from the first energy consumption state to the second energy consumption state at least partially in response to the plurality of particle sensors detecting the particle count of each compartment/zone no longer exceeds the corresponding predetermined compartment/zone particle count.

18. The clean room control system of claim 13 , wherein, in response to the opening of a clean room door at a time when the clean room is either in the second energy consumption state or is in transition from the first energy consumption state to the second energy consumption state, the controller is operative for adjusting the speeds of the fans and the positions of the dampers substantially simultaneously to preset speeds and positions or to speeds and positions associated with the first energy consumption state.

19. The clean room control system of claim 13 , wherein, the controller is further operative:

for storing the speeds of the fans and the positions of the dampers associated with each energy consumption state; and

for causing the speeds of the fans and the positions of the dampers associated with each energy consumption state to return to the stored speeds and positions upon entering said energy consumption state.