Cleaning system for a washer

• US 6,257,254 B1
• Filed: 11/14/1997
• Issued: 07/10/2001
• Est. Priority Date: 11/14/1997
• Status: Expired due to Term

• Current Assignee: Steris Corporation
• Original Assignee: Steris Corporation
• Inventors: Thibault, Nathalie, Parent, Ghislain, Emond, Michel, Rochette, Daniel, Duchaine, Mario, Lemay, Michel, Theriault, Yves-André
• Primary Examiner(s): Stinson, Frankie L.
• Application Number:
  US08/970,406
• Time in Patent Office: 1,334 Days
• Field of Search: 134/111, 134/105, 134/113, 134/172, 134/173, 134/198, 134/57.D, 134/100.1, 134/123, 239/289, 239/239, 239/264, 239/215, 239/242, 239/243, 68/17.R, 682/07
• US Class Current: 134/105
• CPC Class Codes: A01K 1/031 Cages for laboratory animals; Cages for measuring metabolism of animals
• CPC Class Codes: B08B 3/02 Cleaning by the force of jets or sprays

Abstract

A high pressure pump (14) supplies cleaning fluid from a reservoir (12) to spray nozzles (20) inside a washing chamber (10). The spray nozzles (20) spray the cleaning fluid over a load to be cleaned. Used cleaning fluid is collected in a sump (30). A sump pump (32) drains the sump. The combination of the high pressure pump and sump pump provides more efficient cleaning of the load and eliminates the requirement for a deep sump beneath the washer. A vertical traveler (22), having a pair of counterbalanced spray arms (24), raises and lowers the spray nozzles counter cyclically; a detergent injection system (50) accurately meters a correct amount of detergent is added to the cleaning fluid; and a filtration device (34) filters suspended material from the used cleaning fluid and uses a portion of the cleaning fluid to clean itself.

Claims

1. A washer comprising:

a stationary, walk-in washing chamber having a floor, items to be washed in the chamber being wheeled onto the washing chamber floor;

spray nozzles disposed in the washing chamber to spray a cleaning fluid over a load to be cleaned;

a sump below the floor of the washing chamber which collects the cleaning fluid sprayed over the load, the sump being a shallow sump, of less than 12 cm in depth;

a self priming sump pump external to the sump which operates at a low head of fluid to pump at least 250 l/min of cleaning fluid from the sump;

a dip tube which runs between the sump and the sump pump, the sump having a sloping floor which directs the cleaning fluid collected in the sump to the dip tube;

a cleaning fluid reservoir;

a high pressure pump for pumping at least 250 l/min of cleaning fluid from the cleaning fluid reservoir to the spray nozzles;

a temperature booster which raises the temperature of the cleaning fluid from the cleaning fluid reservoir to a preselected wash temperature before the cleaning fluid is delivered to the spray nozzles; and

a fluid injection system connected with the cleaning fluid reservoir for accurately delivering a preselected quantity of a concentrated cleaning fluid to the cleaning fluid reservoir.

2. The washer of claim 1 wherein the high pressure pump delivers cleaning fluid to the spray nozzles at a pressure of about 5 to 15 bar.

3. The washer of claim 2 wherein the cleaning fluid has a flow rate of about 250 l/min.

4. The washer of claim 1, wherein the high pressure pump delivers cleaning fluid to the spray nozzles at a pressure of 7-9 bar.

5. The washer of claim 1 wherein the sump pump is a self-priming pump that operates at a low head of fluid.

6. The washer of claim 1 wherein the sump pump pumps cleaning fluid to the cleaning fluid reservoir.

7. The washer of claim 1 further including:

a detergent injection system which injects detergent into the cleaning fluid reservoir, the detergent injection system including a supply of detergent and a metering pump.

8. The washer of claim 1, further including a detergent injection system which injects detergent into the cleaning fluid reservoir, the detergent injection system including:

a supply of detergent and a metering pump;

a flow meter, the flow meter detecting detergent flow in the detergent injection system; and

an alarm which indicates when detergent flow through the flow meter drops below a preselected level.

9. The washer of claim 8, further including:

a water flow meter for metering water added to the cleaning fluid reservoir; and

a control circuit to cause the metering pump to meter an amount of detergent into the reservoir in proportion to the water added.

10. The washer of claim 9 wherein the controller determines the amount of detergent to be added by the peristaltic pump as a function of a predetermined factor input to the controller, the factor being selected from a group including:

detergent concentration, level of soil on the load, type of detergent, proportion of cleaning fluid reused, and type of cycle.

11. The washer of claim 8, wherein the metering pump delivers a number of pulses of detergent to the cleaning fluid tank, the number of pulses determined by an amount of detergent to be added.

12. The washer of claim 1 further including an in-line temperature booster which raises the temperature of the cleaning fluid from the cleaning fluid reservoir to a preselected wash temperature shortly before the cleaning fluid is delivered to the spray nozzles,

whereby heating the cleaning fluid in the sump is avoided.

13. The fluid injection system of claim 1, further including a peristaltic pump which delivers pulses of the fluid, the preselected quantity of concentrated cleaning fluid measured in terms of a number of the pulses of fluid delivered by the peristaltic pump.

14. The fluid injection system of claim 1, the injection system further including an alarm, the alarm indicating when the flow meter detects a fluid flow below a preselected level.

15. The washer of claim 1, further including:

a vertical traveler including;

a pair of counterbalanced spray arms, disposed adjacent opposite sides of the washing chamber, the spray nozzles disposed on the spray arms,

a mechanism which supports the spray arms for vertical travel of the spray arms,

a drive system which alternately raises and lowers the spray arms, the drive system including a drive cable,

a break-away connection between the drive cable and the mechanism for disconnecting the cable from the mechanism, and

a safety cable connected to the mechanism which prevents the pair of spray arms from simultaneously moving in a downward direction.

16. A washer comprising:

a washing chamber;

spray nozzles disposed in the washing chamber to spray a cleaning fluid over a load to be cleaned;

a pump for pumping cleaning fluid to the spray nozzles;

a sump which collects the sprayed cleaning fluid;

a sump pump which pumps the cleaning fluid from the sump;

a vertical traveler including;

a pair of counterbalanced spray arms, disposed adjacent opposite sides of the washing chamber, the spray nozzles disposed on the spray arms,

a mechanism which supports the spray arms for vertical travel of the spray arms, and

a drive system which alternately raises and lowers the spray arms the drive system including;

a drive cable, and

a drive means engaging the drive cable and sequentially moving the cable alternately a preselected distance in a first direction and an equivalent distance in a second direction, the second direction being the reverse of the first direction,

the drive cable connected to the mechanism, the cable defining a path from the drive means to each of the pair of spray arms in turn and then to the drive means;

whereby the alternating movement of the cable causes first and second spray arms to travel vertically in opposite directions.

17. The washer of claim 16 wherein the drive means includes a rodless pneumatic pump.

18. A washer comprising:

a washing chamber;

spray nozzles disposed in the washing chamber to spray a cleaning fluid over a load to be cleaned;

a pump for pumping cleaning fluid to the spray nozzles;

a vertical traveler including;

a pair of counterbalanced spray arms, disposed adjacent opposite sides of the washing chamber, the spray nozzles disposed on the spray arms,

a mechanism which supports the spray arms for vertical travel of the spray arms, and

a drive system which alternately raises and lowers the spray arms, the drive system including a drive cable,

a break-away connection between the drive cable and the mechanism for disconnecting the cable from the mechanism, and

a safety cable connected to the mechanism which prevents the pair of spray arms from simultaneously moving in a downward direction.

19. A washer comprising:

a washing chamber;

spray nozzles disposed in the washing chamber to spray a cleaning fluid over a load to be cleaned;

a sump at the bottom of the washing chamber which collects the cleaning fluid shaved over the load;

a sump pump which pumps cleaning fluid from the sump;

a cleaning fluid reservoir which receives cleaning fluid from the sump pump;

a fluid injection system connected with the cleaning fluid reservoir for accurately delivering a preselected quantity of a concentrated cleaning fluid to the cleaning fluid reservoir;

a high pressure pump for pumping cleaning fluid from the cleaning fluid reservoir to the spray nozzles; and

an in-line temperature booster connected with a fluid flow line between the cleaning fluid reservoir and the spray nozzles which raises the temperature of the cleaning fluid from the cleaning fluid reservoir to a preselected, elevated wash temperature as the cleaning fluid is delivered to the spray nozzles.

20. A washer comprising:

a pair of counterbalanced spray arms, disposed adjacent opposite sides of the washing chamber, spray nozzles disposed on the spray arms to spray cleaning fluid over the load;

a mechanism which supports the spray arms for vertical travel of the spray arms along sides of the washing chamber;

a drive system which counter cyclically raises and lowers the spray arms such that one arm is raised as the other arm is lowered;

a sump at the bottom of the washing chamber which collects the cleaning fluid sprayed over the load;

a sump pump which pumps cleaning fluid from the sump;

a cleaning fluid reservoir;

a high pressure pump for pumping cleaning fluid from the cleaning fluid reservoir to the spray nozzles; and

a fluid injection system connected with the cleaning fluid reservoir for accurately delivering a preselected quantity of a concentrated cleaning fluid to the cleaning fluid reservoir.

21. A washer comprising:

a washing chamber;

spray nozzles disposed in the washing chamber to spray a cleaning fluid over a load to be cleaned;

a sump at the bottom of the washing chamber which collects the cleaning fluid that has been sprayed over the load;

a sump pump which pumps cleaning fluid from the sump;

a cleaning fluid reservoir;

a high pressure pump for pumping cleaning fluid from the cleaning fluid reservoir to the spray nozzles; and

a vertical traveler including;

a pair of counterbalanced spray arms, disposed adjacent opposite sides of the washing chamber, the spray nozzles disposed on the spray arms,

a mechanism which supports the spray arms for vertical travel, and

a drive system which alternately raises and lowers the spray arms, the drive system including;

a drive cable, and

a drive means engaging the drive cable and sequentially moving the cable alternately a preselected distance in a first direction and an equivalent distance in a second direction, the second direction being the reverse of the first direction,

the drive cable connected to the mechanism, the cable defining a path from the drive means to each of the pair of spray arms in turn and then to the drive means;

whereby the alternating movement of the cable causes first and second spray arms to travel vertically in opposite directions.

22. A washer comprising:

a washing chamber;

spray nozzles disposed in the washing chamber to spray a cleaning fluid over a load to be cleaned;

a sump at the bottom of the washing chamber which collects the cleaning fluid sprayed over the load;

a sump pump which pumps cleaning fluid from the sump;

a cleaning fluid reservoir;

a high pressure pump for pumping cleaning fluid from the cleaning fluid reservoir to the spray nozzles; and

a vertical filtration device which selectively filters cleaning fluid drawn from the sump and uses a portion of the cleaning fluid to clean the filtration device of suspended material removed from the cleaning fluid by the filter filtration device, the filtration device including;

a chamber, and

a filtration screen within the chamber which filters suspended material from the cleaning fluid, the filtration screen being vertically aligned such that the portion of the cleaning fluid used to clean the filtration device enters the filtration device above the filtration screen, contacts the filtration screen, and leaves the filtration device below the filtration screen.

23. The washer of claim 22 wherein the filtration device further includes:

a fluid inlet defined in a wall of the chamber which receives cleaning fluid drawn from the sump;

a first fluid outlet defined in a wall of the chamber which directs unfiltered cleaning fluid from the filtration device to a drain;

a valve which selectively closes to prevent cleaning fluid from exiting the filtration device through the first fluid outlet; and

a second ruled outlet defined in a wall of the chamber which directs cleaning fluid, filtered of suspended material by the screen, to the cleaning fluid reservoir.

24. The washer of claim 23, wherein the screen defines a cylinder and is disposed in the filtration chamber with open ends of the cylinder surrounding the fluid inlet and the first outlet respectively, the filtration device further including:

first and second gaskets disposed around the open ends to seal the screen to the filtration chamber.