metal chip systems

8/18/2019 Metal Chip Systems

1/15

excellence in engineering - since 1933

METAL CHIP

PROCESSING

SYSTEMS


2/15

THE NATIONAL ADVANTAGE

2

WORLDWIDE RECOGNITION

National metal chip processing systems have been

selected by leading manufacturers in North America,Europe, Latin America and Asia, handling the followingypes of metal scrap:

• Aluminum • Cast Iron• Mixed Metal Waste • Bronze• Die Casting Scrap • Stainless Steel

• Brass • Magnesium• Stamping Scrap • Carbon Steel• Nodular Iron • Titanium

THE NATIONAL “NO COMPROMISE”

APPROACH

National takes a “No Compromise” approach to system

design and supply. Unlike other suppliers, we do not imposeon our customers the application of various items of propri-etary equipment with advice that one or two such designs can

serve a multitude of needs. National consistently adheres tohe practice of selecting the best equipment available - for

each particular application - rather than trying to fit equipmentonly manufactured by National to the project. We have

developed long standing alliances with many machinerymanufacturers - an arrangement which permits us to selectand economically package the most suitable items of

equipment for each application. This tailor made approachhas important benefits for the system user in terms of

optimum, trouble-free performance.

SINCE 1933

A PIONEER AND LEADER

Founded in 1933, National pioneered metal chip procesduring World War II. The War Production Board seleNational Conveyors Company to develop processes for

recovery and recycling of metal wastes generated frommanufacture of aircraft, ships, tanks, munitions and o

military equipment. National engineers and desigsucceeded in this effort, establishing the basic technolog

metal chip processing as it is known today. In recognitiothis achievement, the Company was awarded several Government citations. Since then, National has establish

worldwide reputation as a leader in this field and continthis worthy tradition by providing economical state of

art solutions.

A REPUTATION FOR PRODUCT QUALITY

AND FOLLOW UP SERVICE National’s customers regularly commend the quality o

systems - both in terms of performance and maintenaHundreds of National systems are now providing trouble

performance after 20, 30, or more years of continuoperation.

After-the-sale service is a strong tradition at National.

local representatives and factory based engineers

technicians carry out periodic on-site visits to review sysperformance and offer useful recommendations.

SMALL OR LARGE SYSTEMSWhether your needs call for a small, pre-engineered, salone system or a custom high capacity, multi-metal, com

er controlled chip processing system, National can serve needs with economical, leading edge technology and heduty, low maintenance equipment.

OFFICES AND PLANTNATIONAL CONVEYORS COMPANY

excellence in engineering since 1933


3/15

OBJECTIVES/DESIGN CONSIDERATIONS

CHIP PROCESSING OBJECTIVES

There are several economic, operational, environmental and safety related reasons

for the use of metal chip processing systems. Principal reasons or objectives include:1. Obtain an optimum price for metal scrap - through upgrading.

2. Optimize the physical characteristics of scrap for internal reclaim (re-melt) operations.

3. Reclaim and recycle costly cutting oils.

4. Minimize in-plant waste handling costs.

5. Compliance with pollution control regulations.

6. Compliance with worker health & safety requirements.

TYPES OF METAL SCRAPProper system design and equipment selection depends upon having a thorough understanding of the physical characteristi

of the scrap to be handled and processed. This understanding is critical to the selection of the type of conveyors, classificatioequipment and size reduction equipment. Some of the more common types of metal scrap are pictured below.

BROKEN CHIPS: Also known as shovelinghips. This material is free flowing and has nor-

mally been crushed to a particle size of 1” - 2”25mm-50mm). The compact nature of suchhips and extensive surface area retainsonsiderable coolant. Density and weight varies

with metal type.

BUSHY TURNINGS (TIGHT): This materialconsists mostly of spirals, long strings andhelixes together with some smaller particles.During its production and handling it has becomecompressed in some manner. Medium bulkdensity depending on metal.

BUSHY TURNINGS (LOOSE): Similar maas found in the tight version but tends to folight, fluffy bundles which are more difficconvey and process. Low bulk density.

RON BORINGS & CHIPS: This scrap isenerally finer in size structure - typically frombout 3/16” (4mm) to dust and may host aonsiderable amount of coolant. High bulkensity.

DIE CASTING SCRAP: Risers, sprues and thelike, removed following the casting process.Particle size varies and may include larger piecesof reject or broken castings. Bulk densitydepends upon metal type.

STAMPING SCRAP: Generated by perfoand trimming operations. Generally free floTypical particle size range is 1” (25mm) (200mm) in the major dimension. Thinner gaare more difficult to handle. High bulk densi


4/15


5/15

A SYSTEM FOR ANY NEED

6

National chip systems process cast iron and aluminum chips at large engine plant.

Chip processing and load out system at transmission components plant. National-Arboga crusher and chip wringer in background.Motorized swivel chutes distribute chips to roll off containers.


6/15

National chip processing systems installed at a major U.S. automotive components plant.

National “Stand Alone” chip processing system processes steel turnings.Dry chips are pneumatically conveyed to containers.


7/15

CHIP COLLECTION & CONVEYING

8

MECHANICAL CONVEYING

Several different types of mechanical conveyors are used to convey metal chips and turnings. Each has its own uniquebenefits where properly applied. The physical characteristics of the material to be handled must be carefully studied to

insure the correct selection of conveyor. A wrong choice, based on inexperience or overemphasis on initial cost, can leadto undesirable consequences. National provides the following types of mechanical conveyors.

DRAG FLIGHT CONVEYOR

Used for conveying broken, crushed or finely sized chips only.Suitable for both horizontal and inclined runs. Do not use

where stringy (bushy) turnings are present as these will cause

jamming of the drag chains. The usual configuration is a rec-tangular trough fitted with a single strand or two parallel strandsof drive chain to which vertical drag flights are attached -

providing the conveying mechanism.

HINGED STEEL BELT (APRON) CONVEYOR

A multi-purpose metal scrap conveyor useful for a combinationof horizontal and elevating runs. It is used as an elevating

conveyor for wet or dry coarse chips or bushy scrap. National’sbelt includes special tight formed hinge loops and arc welded

side wings to preclude common wear and jamming problems

encountered with conventional steel belt designs.

SCREW (HELICOID) CONVEYOR/FEEDER

Screw conveyors may be properly applied for short horizontalor inclined runs. Also frequently used as controlled rate feedersfitted to the bottom of storage bins or surge hoppers. National’s

design usefully features constant thickness, abrasionresistant flights continuously welded to an oversized, heavy

wall pipe shaft.

PUSH-BAR CONVEYOR

A reciprocating stroke (push-pull) plow mechanism moves

material in the desired direction. Especially effective forhandling bushy, stringy bundles and mixtures of bushy and fine

chips together with large volumes of coolant. Normally installedat or below floor level. Coolant removal can be aided by use of

wedge wire screen panels at selected points, draining intoa sub trough.


8/15

CHIP CONVEYING - PARTS SEPARATIO

PNEUMATIC CONVEYING

PARTS/SOLIDS SEPARATION

National Conveyors is the leading designer and supplier

of metal chip pneumatic conveying systems. Pneumatic

transport has the following advantages over mechanicalconveying: (1) Lower capital cost, (2) much lowerinstallation cost and (3) lower system maintenance cost.

Two design options are offered by National:

• Dilute phase pneumatic conveying

• Dense phase pneumatic conveyingDilute phase pressurized air systems can be used forconveying chips at medium pipeline velocities fordistances of 2,000 feet (610m) or longer. Dense phase

pressurized air systems are used for low velocityconveying of wet or dry chips.

Properly designed chip processing systems must includeprovision for separation of parts and unwanted tramp

oversize material which may unavoidably be mixed withmetal scrap. Such items can cause damage to down-

stream equipment.

VIBRATING GRIZZLY OR SCREEN Vibrating grizzlies and vibrating screens are used to sortsolids by size. The vibrating grizzly is a coarse material

screening device having a number of parallel barelements spaced for the desired size of separation.

Vibrating screens are normally used for feeds from whichlarger objects have already been removed and a moreaccurate final product sizing is desired. The selection of

screen decking is a critical consideration and is dependentlargely on the physical configuration of the feed material.

Photograph above shows a National double gate air lock type chip

feeder used for regulating chip feed to dilute phase conveying system.

Photograph at left shows a dense phase pneumatic transporter used forfeeding metal chips into the conveying pipeline. Chips are delivered to the

top of the transporter where oversize material is scalped and removedthrough the inclined chute.


9/15

PARTS SEPARATION

10

When parts of other solids must be scalped from bushymetal turnings, the National parts separator shown heremay be usefully applied. Chips and turnings together with

occasional parts, bar ends or other larger items aredelivered by conveyor to the feeder pan which is

mechanically oscillated with a sideways action. Thiscondition causes long narrow items to orient themselves

so as to easily report through the reject slot. Pressurized

air flow passing upwards through the reject slot hassufficient buoyant force to carry metal chips and turningsover the slot opening. Heavier parts and tramp meta

items are not supported by the induced air flow and passdownward into a collecting hopper from which they

discharge into a container. Air flow is vented from the topof the discharge hood and can be recirculated when

required.

Size reduction of metal scraps by crushing or shredding

is commonly performed when material larger than about1-1/2” (38mm) is being generated (such as machine turn-ings). Size reduction is beneficial in these ways:

• crushed scrap commands a higher market price

• reduces stringy, bushy scrap to a smaller size,

making handling easier

• enhances recovery of cutting oils and coolants

during the chip wringing (centrifuging) process

• produces a product with higher bulk density(greater weight per unit volume) minimizing

handling, transport and storage costs

Moreover, crushing is often an essential process step

when pneumatic conveying, bin storage, briquetting orthermal drying is employed.

Three types of crushers and shredders are commonlyused in chip processing systems:

• vertical shaft (crusher) shredder

• horizontal shaft two roll shredder• horizontal shaft, ring type crusher

(Hammermill)

National offers all three. They are briefly described on the

following page.

NATIONAL PARTS SEPARATOR

CRUSHING AND SHREDDING

AIR EXHAUST

REJECTSLOT

REJECTS

TURNINGS

PARTS SEPARATOR

FEED

FEEDERPAN

BLOWER

AIR INTAKE


10/15

CRUSHING & SHREDDIN

NATIONAL

VERTICAL SHAFT

CRUSHER/SHREDDER

A highly efficient machine forcoarse or fine particle sizereduction. Metal turnings are

drawn downward by the rotat-ing feeder arm. Side wall cut-

ters break up bundles. Finalreduction occurs in the lower

throat zone which is fitted withrotating and fixed cuttingtools. Automatic parts (solids)

rejection is an importantfeature (see Bulletin 1200A).

NATIONAL HORIZONTAL

SHAFT TWIN ROLL

SHREDDER

Useful as a bundle breakerand for coarse to medium size

reduction, counter rotatingshafts (rolls) are fitted with

toothed cutting rings. Turnings

fed at confluence of rolls aredrawn inward where shred-

ding occurs. Shredder can behydraulically or mechanically

driven.

ROLLING RING TYPE

CRUSHER

An excellent machine formedium and fine crushing of

metal turnings. Hammer ringsheld by rotating arms smash(crush) incoming turnings

against a manganese steelbreaker plate and grate bars

located in the bottom of thecrushing chamber. Product

size is controlled by gratebar opening. Crusher has pro-vision for rejecting oversize

solids.

LARGE SOLIDS ARE REJECTED BYROTATING CRUSHER RINGS,CAUSING THIS MATERIALTO REPOTO OVERSIZE BYPASS CHUTE

FEEDCONVEYOR

TRAMP METAL

CRUSHED CHIP DISCHARGE

ROTORSHAFT

TRAMPOVERSIZE

MANGANESESTEEL

GRATE BARS

MANGANESESTEEL LINERS

SECONDARY TRAMETAL DISCHARG

PROTECTHOUSIN


11/15

CHIP WRINGING (CENTRIFUGING)

12

The chip wringer (centrifuge) is the heart of any chip processing system. This is where the principal goal of extractingresidual cutting fluids is accomplished. National offers both horizontal and vertical bowl centrifuge designs. These are

described below.

HORIZONTAL BOWL SELF-CLEANING CENTRIFUGE

The National Horizontal Bowl Self Cleaning Centrifuge has become the preferred device for chip wringing at major metal

working plants in the U.S.A. and internationally. Both fixed bowl and adjustable bowl models are offered. Design featuresand user benefits include:

• HIGH EFFICIENCY LIQUID/SOLIDS SEPARATION

Up to 550 gravities of centrifugal force and uniform feeddistribution assure optimum dewatering performance.

• CONTROLLED LIQUID SEPARATION PERFORMANCE

The bowl may be positioned so as to provide a selecteddrainage screen exposure which results in the desiredproduct dryness.

• SELF-CLEANING, HORIZONTAL BOWL DESIGN

When the centrifuge is coasting to the stoppedcondition, the residual chip load tumbles from themachine leaving it in a clean condition for the next startup (see photograph below).

• EASY INSPECTION & MAINTENANCE

All internal wetted parts can be inspected in 5 minutes.Simply open the hinged front door. The motor and drivecomponents are externally mounted.

HOW IT WORKS

Wet chips enter the centrifuge through the feed inlet hopper (1) and delivery chute (2) from which they are uniformly

distributed across the surface of the rotating bowl (3), aided by feed distribution vanes. Newly arrived wet chips moveoutward over the rotating bowl surface, discharging onto a rotating, cylindrical wedge wire drainage screen element (4).New chips move onto the screen surface displacing previously arrived chips. Separation of liquid occurs as chips pass

over the drainage screen. Dewatered chips fall through the solids discharge chute (5) from which they are normallycollected by a conveyor. Liquid which has passed through the drainage screen element (4) flows through the liquid

discharge chute (6) for collection.

National Model HD82VS Horizontal Bowl Centrifuge

View shows self cleaning actionwhen centrifuge is coasting to

the stopped position.

Bowl positioned for maximumdrainage screen exposure

Bowl positioned for minimumdrainage screen exposure

OPTIONAL PATENTED FEATURE

AVAILABLE WITH VARI-SCREEN T.M. MODEL

Usefully, by simple external adjustment, the bowl (3)may be moved laterally back and forth over thedrainage screen surface (4) thereby establishing thebest choice of screen exposure for optimum liquidremoval and the achievement of desired product dry-ness. Positioning of the bowl is easily accomplished

by rotation of the external adjustment mechanism (7).

U.S. PATENTS5,788,8615,855,800FOREIGN PATENTS PENDING

Ask for Bulletin No. 900-2


12/15

CHIP WRINGIN

National Model TI-30 pneumatic discharge centrifuge instalat a major aircraft manufacturer.

Model SC 100 KC Chip Wringer Ask for Bulletin No. 0299-R

VERTICAL BOWL, PNEUMATIC DISCHARGE TYPE CENTRIFUGE

HOW IT WORKS (See Below)Chips and cutting fluids (coolants) are fed into a conical inlet hopper (1) reporting to the bottom of the rotating bowl

The bowl is mounted on a heavy-duty shaft and bearing assembly (3), driven by a non-slip timing belt and shearrangement (4) and easily accessible foot-mounted motor (5). Chips and fluids arriving within the bowl are immedia

subjected to a high centrifugal force. This centrifugal force causes both chips and fluids to be thrown against the bowl surfThe arrival of additional (new) chip feed causes chips already present on the bowl to be displaced in an upward direction a

the bowl surface. As chips and fluid arrive at the upper periphery of the bowl, they pass across a stainless steel wedge screen (6) through which cutting fluids are centrifugally expelled into a discharge chamber (7) from which this fluid flodirected to a coolant collecting sump (not shown) for subsequent treatment or disposal. Dried chips pass across the sc

into the chip discharge housing (8) from which they are pneumatically expelled by the airflow generated by fan blades (9)discharge piping (10). The airflow generated by the wringer is normally adequate for conveying chips for a distance of u

about 100ft. (30m). Typically, the pneumatic discharge pipe delivers dried chips to a roll-off container, truck or interim storage

BATCH TYPE CHIP WRINGER

The National-Rousselet “Timesaver” chip wringer centrifuge is an efficient and economical device for manual, bprocessing of metal chips and turnings. An excellent choice for smaller machining operations. Three high capacity (la

saving) models are offered having basket volumes of 10 cu. ft. (290 I.), 16 cu. ft. (460 I.) and 32 cu. ft. (900 I.) Rugged 3 psuspension. Controlled acceleration and smooth braking. There is no other comparable batch type centrifuge.


13/15

CHIP LOAD OUT

14

The final phase of any chip processing system - chip load

out - must be designed to accommodate both the present

and potential future needs of each installation. Normally.processed chips are loaded directly into containers, trucks

or rail cars. In some cases, chips may be conveyed tostorage silos or bins from which they are loaded into trucks

or rail cars. Conventional chip load out systems employboth mechanical and pneumatic conveying methods

together with various types of fixed or moveable chutes,

slide gates, or the like. When the chip load out station is

located a considerable distance from the chip processing

system, pneumatic conveying is a preferred transfermethod.

National offers its exclusive “Vari-Slot” overhead load out

conveyor system. Acknowledged as the most advancedstate of the art method for uniformly distributing chips into

containers or trucks, it is described on the following page.

Mechanical conveyor discharges to swivel chute providing ameans for loading two roll off containers.

National pneumatic discharge type centrifuge can convey chipsfor a distance of about 100 ft. (31m)

Above: National supplied long distance pneumaticconveying system carries processed chips approx-imately 2,000 ft. (610m) to interim storage silos.

At Left: A screw type feeder is used to evacuate thebin in the foreground. A live bottom vibrating actu-ator is fitted to the other bin.


14/15

VARI-SLOT TM TRUCK LOADING CONVEYO

The National “Vari-Slot” T.M. load out conveyor is a unique

design of overhead drag type conveyor used for uniformdistribution of bulk materials into trucks, rail cars, containers

or bunkers.

The discharge station of the conveyor is comprised of one or

more sections, each fitted with an articulating bottom platewhich may be controllably positioned to provide the desired

material discharge pattern.

Individual articulating bottom plates may be positioned

zero discharge, maximum discharge or a selected intermate rate of discharge.

The choice of which conveyor bottom plates are left closed position and which plates are positioned to pe

material discharge depends on the desired distribupattern and the length of the trailer or container to be loa

Generally speaking, the “vari-slot” conveyor is usedloading trailers, rail cars or containers ranging in le

between 20 ft. and 60 ft. (6m to 18m).

Multiple National “Vari-Slot” loading conveyors are used for metalchip loading at an automotive parts manufacturing plant.

• EXCEPTIONALLY UNIFORM

LOAD DISTRIBUTION

• MINIMUM HEAD ROOM, NO

CHUTES OR GATES ARE

REQUIRED

Ask for Bulletin No. 900-01

“Vari-Slot” T.M. conveyor in operation

THE MOST EFFICIENT AND ECONOMICAL METHOD FOR TRUCK OR RAIL CAR LOADIN

THE APPARATUS AND METHOD OF THENATIONAL VARI-SLOT CONVEYOR ISPATENTED. U.S. PATENT NO. 6,109,425.FOREIGN PATENTS PENDING.

excellence in engineering since 19

CONVEYOR DISCHARGE SECTION

FEED STATION

TRAILERS OR CONTAINERSOF VARYING LENGTHS CANBE QUICKLY AND EASILYACCOMMODATED


15/15

DEWATERING SYSTEMS FOR GRINDING SWARF

AND DISPOSABLE FILTER MEDIA

33 Nicholson Road, East Granby, CT 06026 Tel. (860) 653-0374 Fax (860) 653-2965

ENGINEERS & MANUFACTURERS

Since 1933

REDUCE THE COST OF METAL

SLUDGE DISPOSAL WITH A

NATIONAL-SEBRIGHT HIGH

DENSITY EXTRUDER

The National-Sebright High Density

Extruder is a highly efficient machine for

dewatering metal grinding sludge (swarf)

and saturated disposable filter media.

Sludge (swarf) volume can be

reduced by 50% or more

The dry, cake-like discharge product

will generally be suitable for disposal

in a local landfill, with considerable

savings over other specialized dis-

posal arrangements.

Achieve compliance with Federal and

State regulations governing the

handling of wet waste.

Several machine sizes are available.

Pilot testing of your swarf can be

arranged.

Ask for Bulletin No. 1101 for complete

details.

The photographs at the right show cast

ron grinding sludge (swarf) before and

after processing in a High Density

Extruder.

National-Sebright High Density Extruder installedat automotive components manufacturing plant.

CONVERT THIS..................................................... TO THIS

metal chip systems

Documents