Microprocessor based pump controller for backwashable filter

• US 4,676,914 A
• Filed: 03/18/1985
• Issued: 06/30/1987
• Est. Priority Date: 03/18/1983
• Status: Expired due to Fees

• Current Assignee: North Coast Systems Incorporated
• Original Assignee: North Coast Systems Incorporated
• Inventors: Grys, Rodger J., Mills, Donald E.
• Primary Examiner(s): Fisher, Richard V.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/712,897
• Time in Patent Office: 834 Days
• Field of Search: 210/108, 210/138, 210/741, 210/89, 210/90, 210/416.2, 210/169, 210/134, 210/141, 417/12, 417/33, 417/44, 364/500, 364/502, 55/96, 55/283
• US Class Current: 210/741
• CPC Class Codes: E04H 4/1245 Recirculating pumps for swimming pool water
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 2207/043 of time
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04

Abstract

A pump (B) pumps water from a swimming pool (A) to a forward/reverse direction control valve (D). The control valve (D) has a first or forward flow state in which it channels water into an inlet (20) of a filter (C) and from a filter outlet (24) back to the swimming pool and a second state in which it channels the water into the fluid outlet (24) and from the fluid inlet to a drain (28). A microprocessor based electronic control circuit (E) selectively actuates the pump at preselected intervals for preselected durations such that the water from the swimming pool is intermittently filtered. The control circuit further monitors the fluid pressure with a low pressure limit switch (46). In response to the pumped fluid pressure failing to achieve a low limit within a preselected duration, the control circuit terminates operation of the pump. Further, the control circuit monitors the water pressure with a high pressure limit switch (48). In response to the monitored pressure exceeding the high limit, the control circuit causes the forward/reverse valve (D) to assume its second state and backwash the filter automatically. The microprocessor also calculates the volume of fluid discharged through a drain, which is automatically replaced with fresh fluid.

Claims

1. A method of controlling the circulation of a fluid through a filter, the method comprising cyclically repeating the steps of:

selecting a filter flow path which directs a flow of fluid through the filter in a forward filtering flow direction;

pumping the fluid under pressure;

sensing the pressure of fluid adjacent the filter; and

,

with a microprocessor;

selectively monitoring the sensed fluid pressure;

comparing the sensed fluid pressure with a preselected high limit;

in response to the sensed pressure exceeding the high limit, stopping the pumping of the fluid;

after stopping the pumping, selecting a backwash flow path which directs the flow of fluid through the filter in a reverse, backwashing flow direction;

after selecting the backwash flow path, recommencing pumping the fluid to backwash the filter, and discharging at least a portion of the fluid through a drain line;

after a backwash duration, stopping the pumping of the fluid and selecting a flow path which again directs the fluid through the filter in the filter direction;

determining a volume of fluid discharged through the drain line; and

,

replacing the discharged fluid with a like volume of fresh fluid.

2. A method of controlling the circulation of a fluid through a filter, the method comprising cyclically repeating the steps of:

selecting a filter flow path which directs a flow of fluid through the filter in a forward filtering flow direction;

pumping the fluid under pressure;

sensing the pressure of fluid adjacent the filter; and

,

with a microprocessor;

selectively monitoring the sensed fluid pressure;

determining whether the sensed fluid pressure exceeds a preselected low limit;

in response to the sensed pressure failing to exceed the low limit within a selected duration of commencement of pumping, causing termination of the fluid pumping step, whereby pumping is terminated in response to a low pressure limit to protect pumping equipment from damage;

comparing the sensed fluid pressure with a preselected high limit;

in response to the sensed pressure exceeding the high limit, causing selection of a backwash flow path which directs the flow of fluid through the filter in a reverse, backwashing flow direction;

after selection of the backwash flow path, causing the fluid to be pumped back to the filter; and

,

after a backwash duration, causing termination of the pumping of the fluid.

3. An apparatus for controlling the circulation of water through a water filter to selectively filter the water and backwash the filter, the apparatus comprising:

a flow direction control means for selectively controlling the circulation of the water through the filter to circulate the water therethrough selectively in one of a first or filtering direction and a second or backwash direction;

a fluid pumping means for selectively pumping the water through the flow direction control means to the filter;

a pressure sensing means for sensing water pressure adjacent the filter; and

,

a microprocessor operatively connected with the pumping means, the flow direction control means, and the pressure sensing means, the microprocessor including;

a pump control means for selectively causing the pumping means to pump the water,

a flow direction selection means for selectively causing the flow direction control means to direct the water through the filter in one of the filtering and backwash directions,

a filter timing means for selectively causing the pump control means to actuate the pumping means at selected intervals for selective durations while the flow direction control means is directing water through the filter in the filtering direction,

a first timing means for timing a first duration from actuation of the pumping means,

a pressure sensor monitoring means for monitoring the pressure sensing means and providing an electrical signal indicative of the sensed water pressure;

a low pressure determining means for comparing the electrical signal from the pressure sensor monitoring means with a preselected low limit, the low pressure determining means being operatively connected with the first timing means and the pump control means for selectively blocking operation of the pumping means in response to the sensed pressure failing to exceed the low limit within the first duration,

a high pressure determining means for comparing the electrical signal from the pressure sensor monitoring means with a preselected high limit, the high pressure determining means being operatively connected with the flow direction selection means to direct the fluid through the filter in the backwash direction, and

a backwash timing means for actuating the pump control means for a preselected backwash duration such that water is pumped through the filter in the backwash direction for the preselected backwash duration.

4. An apparatus for controlling the circulation of water through a filter, the apparatus comprising:

a flow direction control means for selectively controlling the direction in which the water is circulated through the filter between a filtering direction and a backwash direction;

a pumping means for selectively pumping water to the flow direction control means under pressure;

a pressure sensing means for sensing the water pressure adjacent the filter;

a drain line operatively connected with the flow direction control means for discharging at least a portion of the water pumped through the filter in the backwash direction,

a replacement water supply means for selectively supplying fresh water; and

,

a microprocessor operatively connected with the flow direction control means, the fluid pumping means, the pressure sensing means, and the replacement water supply means, the microprocessor including;

a pump control means for selectively actuating the pumping means to pump water;

a filter cycle timing means for selectively enabling the pump control means to actuate the pumping means at selected intervals for selected filter durations;

a high pressure determining means operatively connected with the pressure sensing means for determining whether the sensed water pressure exceeds a preselected high limit;

a flow direction selecting means for selectively causing the flow direction control means to change the direction of water flow through the filter between the filtering direction and the backwash direction in response to the sensed pressure exceeding the high limit;

a backwash timing means for actuating the pumping means to supply water under pressure through the filter in the backwash direction for a backwash duration, at least a portion of the water being discharged through the drain line, and for causing the flow selection means to change the direction of flow through the filter at the end of the selected backwash duration to the filtering direction such that the water is again pumped through the filter in the filter direction; and

,

a water replacement means for determining a volume of water discharged through the drain line and for causing the replacement water supply to supply a like volume of fresh water.

5. The apparatus as set forth in claim 4 wherein the water replacement means calculates the volume of discharged water from the water pressure sensed by the pressure sensing means and from the backwash duration.

6. The apparatus as set forth in claim 4 wherein the microprocessor further includes a memory for selectively storing operating instructions and for selectively storing data concerning system malfunctions, which memory loses stored data during a power loss;

and,

a battery backup for automatically supplying electrical power to the microprocessor in the event of a disruption of power supplied by an external power source, such that data stored in the memory of the microprocessor is maintained during the power failure.