Washing process

• US 5,253,379 A
• Filed: 04/20/1992
• Issued: 10/19/1993
• Est. Priority Date: 04/19/1991
• Status: Expired due to Fees

• Current Assignee: Unilever Patent Holdings BV (Unilever PLC)
• Original Assignee: Unilever Patent Holdings BV (Unilever PLC)
• Inventors: Frick, Stefan E., Ploeg, Wijnand, Van der Kinderen, Wilhelmus K., Dusamos, Marcellus G.
• Primary Examiner(s): Coe, Philip R.
• Application Number:
  US07/871,167
• Time in Patent Office: 547 Days
• Field of Search: 8/158, 68/12.18, 68/17 R, 137/5, 137/93
• US Class Current: 8/158
• CPC Class Codes: D06F 2103/22 Content of detergent or additives
• CPC Class Codes: D06F 2105/42 Detergent or additive supply
• CPC Class Codes: D06F 34/22 Condition of the washing liquid, e.g. turbidity
• CPC Class Codes: Y10T 137/034 Controlled by conductivity of mixture
• CPC Class Codes: Y10T 137/2509 By optical or chemical property

Abstract

Washing process in an industrial washing machine, whereby a property of the wash liquor is measured which is dependent on the concentration of detergent product therein, and detergent product is added to the wash liquor, dependent on the property, characterized in that the wash cycle comprises a first period (t₁) in which product is added during a fixed time period to obtain a high concentration in the wash liquor or until the measured property reaches a high set point where it is maintained by gradually adding detergent product, and a second period (t₂) in which the property is kept at a low set point. There is also provided a device for controlling the dosing of detergent product to the process.

Claims

1. Washing process in an industrial washing machine, which comprises contacting a solid load during a wash cycle with a wash liquid which is an aqueous dilution of a detergent product, measuring a property of the wash liquor which is dependent on concentration of detergent product therein, and adding detergent product to the wash liquor, dependent on said property, and wherein the wash cycle comprises a first period (t₁) in which detergent product is added during a fixed time period to obtain a high concentration in the wash liquor or until the measured property reaches a high set point where it is maintained by gradually adding detergent product, and a second period (t₂) in which said property is kept at a low set point.

2. Process according to claim 1, characterized in that the wash cycle comprises a lag period (t_f) preceding the first period (t₁), in which no detergent product is added.

3. Process according to claim 1, characterized in that the wash cycle comprises a last period after the second period (t_l), in which no detergent product is added.

4. Process according to claim 1, characterized in that the measured property of the wash liquor is the electrical conductivity.