US 4,443,232 A · Deaerated liquid stock supply

Abstract

Apparatus for supplying deaerated stock to a processing machine incorporates an enclosed first receiver and a second receiver open to the atmosphere. Stock deaerated by vacuum in the first receiver flows to the second receiver. Some of such stock spills over a weir associated with the second receiver to maintain a constant-level pond in such receiver. Stock is supplied to the machine from such constant-level pond, so that the pond minimizes stock pressure fluctuations at the machine. The stock spilling over the weir is recycled to the first receiver. During a temporary shutdown of the processing machine, the system may be maintained in operation with continuous recirculation of stock through the receivers to facilitate rapid restarting of the machine. Because there is no need for a pond of stock in the enclosed receiver, such receiver may be compact. The system may be installed in a preexisting mill and space within a preexisting vessel may be used for the second receiver.

Claims43

Dependent claims

Apparatus for providing deaerated stock to a processing machine, said apparatus comprising:

(a) an enclosed first receiver;
(b) means for maintaining said first receiver under a vacuum;
(c) means for introducing stock into said first receiver to thereby produce deaerated stock in said first receiver at a predetermined average production rate;
(d) stock supply means for supplying stock to be deaerated to said introducing means;
(e) a second receiver open to the atmosphere;
(f) means for conducting deaerated stock from said first receiver to said second receiver;
(g) means for withdrawing stock from said second receiver at a net rate of withdrawal lower than said average production rate, so that stock accumulates as a pond in said second receiver, said withdrawing means being operative to transfer the withdrawn stock to the processing machine;
(h) level control means for discharging a recycle portion of deaerated stock from said second receiver and varying the rate of such discharge to maintain the pond of stock in said second receiver at a predetermined pond level, said conducting means being operative to discharge deaerated stock into said second receiver at an elevation below said predetermined pond level;
(i) recycle means for passing said recycle stock discharged by said level control means to said introducing means.

6 more elements

A method of supplying deaerated stock to a processing machine comprising the steps of:

(a) introducing stock into an enclosed first receiver and maintaining such receiver under a vacuum to thereby produce deaerated stock at a predetermined average production rate;
(b) conducting said deaerated stock to a second receiver open to the atmosphere and withdrawing deaerated stock from said second receiver and transferring the stock so withdrawn to the processing machine at a rate lower than said production rate, so that a pond of deaerated stock accumulates in said second receiver;
(c) discharging a recycle portion of such stock from said second receiver and varying the rate of such discharge to maintain the pond at a predetermined pond level, the stock conducted from said first receiver to said second receiver being discharged into said second receiver at a location below said pond level;
and
(d) blending other stock to be deaerated with said recycle stock and passing the blended stock to said stock-introducing step.

2 more elements

Dependencies are inferred from the claim text.

Deaerated liquid stock supply

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Deaerated liquid stock supply

Life of this patent

Abstract

Claims43