Method and apparatus for monitoring an underdrain of a filter system

1. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensor for sensing at least one diagnostic condition relating to performance of said underdrain, the method comprising the steps of:

(a) obtaining at least one reading from said sensor relating to performance of said underdrain;

(b) taking said at least one reading within a predetermined time after said filter bed has been washed; and,

(c) determining whether said underdrain is performing at a predetermined acceptable level based at least in part on said reading obtained from said sensor in step (a).

2. A method as recited in claim 1 , further including the step of:

(a) taking said at least one reading within an hour after said filter been has been washed.

3. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensor for sensing at least one diagnostic condition relating to performance of said underdrain, the method comprising the steps of:

(a) obtaining at least one reading from said sensor relating to performance of said underdrain, wherein the at least one reading is pressure of a washing fluid prior to entry into said underdrain; and,

(b) determining whether said underdrain is performing at a predetermined acceptable level based at least in part on said reading obtained from said sensor in step (a) by comparing the pressure of said washing fluid obtained from said sensor to a predetermined pressure value to determine whether flow of fluid through said underdrain is being obstructed.

4. A method as recited in claim 3 , wherein said filter system includes a first pressure sensor positioned downstream of said underdrain relative to direction of flow of a washing fluid and a second pressure sensor positioned upstream of said underdrain relative to direction of flow of a washing fluid, said method further including the steps of:

(a) obtaining a pressure reading from said first pressure sensor and said second pressure sensor to determine a differential pressure.

5. A method as recited in claim 4 , further including the step of:

(a) comparing said differential pressure obtained in step (a) of claim 4 with a predetermined differential pressure value to determine whether flow of fluid through said underdrain is being obstructed.

6. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensor for sensing at least one diagnostic condition relating to flow of fluid through said underdrain, the method comprising the steps of:

(a) obtaining at least one reading from said sensor relating to flow of fluid through said underdrain;

(b) taking said at least one reading within a predetermined time after said filter bed has been washed; and,

(c) determining whether said underdrain is performing at a predetermined acceptable level based at least in part on said reading obtained from said sensor in step (a).

7. A method as recited in claim 6 , further including the step of:

(a) taking said at least one reading within an hour after said filter been has been washed.

8. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a first pressure sensor positioned downstream of said underdrain relative to direction of flow of a washing fluid and a second pressure sensor positioned upstream of said underdrain relative to direction of flow of a washing fluid, said method including the steps of:

(a) obtaining a pressure reading from said first pressure sensor and said second pressure sensor to determine a differential pressure, and,

(b) determining whether said underdrain is performing at a predetermined acceptable level based at least in part on said readings obtained from said sensors in step (a).

9. A method as recited in claim 8 , further including the step of:

(a) comparing said differential pressure obtained in step (a) of claim 8 with a predetermined differential pressure value to determine whether flow of fluid through said underdrain is being obstructed.

10. A method as recited in claim 6 , wherein the at least one reading is pressure of a washing liquid prior to entry into said underdrain.

11. A method as recited in claim 10 , including the further step of:

(a) comparing the pressure of said washing liquid obtained from said sensor to a predetermined pressure value to determine whether flow of the washing liquid through said underdrain is being obstructed.

12. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensing unit for sensing differential pressure across said underdrain, the method comprising the steps of:

(a) at any point in time after said filter system has been filtering a liquid, obtaining a differential pressure across said underdrain to determine whether said underdrain is performing at a predetermined acceptable level.

13. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensor for sensing at least one diagnostic condition relating to performance of said underdrain, the method comprising the steps of:

(a) obtaining at least one reading from said sensor relating to performance of said underdrain, wherein the at least one reading is a pressure reading relating to flow of fluid through said underdrain;

(b) determining flow rate of a fluid directed to said underdrain when said pressure reading is obtained; and,

(c) determining whether said underdrain is performing at a predetermined acceptable level based at least in part on said reading obtained in step (a).

14. A method as recited in claim 13 , further including the step of:

(a) determining whether said underdrain needs to be serviced based at least in part on said pressure reading obtained in step (a) of claim 13 and said flow rate of the fluid determined in step (b) of claim 13 .

15. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensor for sensing at least one diagnostic condition relating to performance of said underdrain, the method comprising the steps of:

(a) obtaining at least one reading from said sensor relating to performance of said underdrain, wherein the at least one reading is a pressure reading relating to flow of fluid through said underdrain

(b) determining flow rate of a washing fluid directed to said underdrain when said pressure reading is obtained; and,

(c) determining whether said underdrain needs to be serviced based at least in part on said pressure reading obtained in step (a) of this claim and said flow rate of the washing fluid determined in step (b) of this claim.

16. A method of monitoring an underdrain of a filter system for filtering a liquid, said filter system including a filter bed and an underdrain operably associated with said filter bed for directing a fluid through said filter bed, said filter system further including a sensor for sensing at least one diagnostic condition relating to flow of fluid through said underdrain, the method comprising the steps of:

(a) obtaining a plurality of readings from said sensor relating to flow of fluid through said underdrain during operation of said filter system to determine when at least one of the following conditions occurs: (i) high pressure and (ii) high fluid flow;

(b) logging said plurality of readings obtained from said sensor; and,

(c) analyzing said logged plurality of readings to determine when at least one of high pressure and high fluid flow events occur during operation of said filter system.

17. A method as recited in claim 16 , wherein:

(a) said plurality of readings are pressure readings.

18. A method are recited in claim 17 , wherein:

(a) at least one of said plurality of pressure readings is taken of fluid prior to entry into said underdrain.

19. A method as recited in claim 16 , wherein:

(a) said plurality of readings are fluid flow rate readings.

20. A method are recited in claim 19 , wherein:

(a) at least one of said plurality of fluid flow rate readings is taken prior to entry into said underdrain.

21. A method as recited in claim 16 , wherein:

(a) said plurality of readings include pressure readings and fluid flow rate readings.

22. A method are recited in claim 21 , further including the step of:

(a) comparing said differential pressure obtained in step (a) of claim 21 with a predetermined differential pressure value to determine whether the flow of fluid through said underdrain is being obstructed.

23. A method as recited in claim 21 , wherein:

(a) said differential pressure obtained in step (a) of claim 21 is derived from a pressure reading relating to a washing fluid flow taken upstream of said underdrain and a pressure reading relating to washing fluid flow taken downstream of said underdrain.