Valley Flat Screen
INTRODUCTION
The Valley Laboratory Flat Screen is designed to answer the industry requirements for a laboratory screen having similar characteristics to a commercially sized limit. Laboratory experimentation with the screen is sufficient to indicate revisions of screen room operation. With this unit, changes can easily be made and their results accurately measured. This can result in important mill cost savings.
Pulp from the digesters can be screened and strength tests run at once, eliminating the time lapse and assuring uniform screening conditions.
STANDARDS
Meets TAPPI T 278 Pulp Screening (Valley Method)
FEATUREs
- Conventional cam and diaphragm action of the commercialsize units
- Vat of cast bronze for an easily replaceable 10" x 12" plate
- Slots for screen plates can be furnished from .004" to .050"
- Screen plates are available in stainless steel.
- 1/3 HP, 115 V, 60 cycle single phase motor
DESCRIPTION
The Valley Laboratory Flat Screen provides a quick test method for pulp as taken directly from the blow pit and as discharged from the digesters. This pulp should be washed, screened in the Valley Flat Screen and then processed in sheet making equipment. The object is to screen in the laboratory in order to obtain the same result as given by the commercial screens in the pulp mill. The Valley Laboratory Flat Screen will handle approximately 8 lbs per hour on 0.10" cut screen plates. This capacity can increase to 20 or 30 lbs per hour as the type of screen plate is varied. Screen plates have been supplied from .004" to .050" cut. The .010" cut plate will handle 8 lbs per hour at a consistency of about 0.02%.
The operation of the Valley Laboratory Flat Screen has to be learned on a trial and error basis. No definite instructions can be set forth since there is no method of continuous feeding or continuous removal of rejects. The pulp slurry must be fed by hand into the deckle box. It is necessary to balance the addition of pulp and the supply of water so that the deckle box does not run over nor does the consistency increase in the deckle box. It will be up to the operator's discretion as to when to add pulp, when to increase or decrease water supply and when to consider screening complete.
In addition, all of the above factors will vary with the type of cook. As a guide, tests on the handsheets so produced should compare to handsheets made with pulp supplied by the commercial screens in the pulp mill. If the level in the deckle box climbs after having operated satisfactorily, it will no doubt be necessary to remove the rejects from the deckle box; if the level drops too quickly, more pulp must be added to the deckle box. Successful operation of the flat screen can only be learned by doing, and in so doing, a pattern can be developed for a specific type of cook.
ORDERING INFORMATION
Catalog Number: prodnumber
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