Notes on Fitting -2

8/11/2019 Notes on Fitting -2

1/22


2/22

Types of Bearings

There are many types of bearings, each used for different purposes. These include ball bearings, roller bearings, ball thrust bearings,

roller thrust bearings and tapered roller thrust bearings.

Ball BearingsBall bearings, as shown below, are probably the most common type of bearing. They are found in everything from inline skates to

hard drives. These bearings can handle both radial and thrust loads, and are usually found in applications where the load is relatively

small.

Photo courtesyThe Timken Company

Cutaway view of a ball bearing

In a ball bearing, the load is transmitted from the outer race to the ball, and from the ball to the inner race. Since the ball is a sphere, it

only contacts the inner and outer race at a very small point, which helps it spin very smoothly. But it also means that there is not very

much contact area holding that load, so if the bearing is overloaded, the balls can deform or suish, ruining the bearing.

!oller BearingsRoller bearingslike the one illustrated below are used in applications like conveyer belt rollers, where they must hold heavy radial

loads. In these bearings, the roller is a cylinder, so the contact between the inner and outer race is not a point but a line. This spreads

the load out over a larger area, allowing the bearing to handle much greater loads than a ball bearing. "owever, this type of bearing is

not designed to handle much thrust loading.

# variation of this type of bearing, called a needle bearing, uses cylinders with a very small diameter. This allows the bearing to fit

into tight places.

Photo courtesyThe Timken Company

Cutaway view of a roller bearing

Ball Thrust BearingBall thrust bearingslike the one shown below are mostly used for low$speed applications and cannot handle much radial load.

Barstools and %a&y Susan turntables use this type of bearing.
http://www.howstuffworks.com/hard-disk.htmhttp://www.howstuffworks.com/framed.htm?parent=bearing.htm&url=http://www.timken.comhttp://www.howstuffworks.com/framed.htm?parent=bearing.htm&url=http://www.timken.comhttp://www.howstuffworks.com/framed.htm?parent=bearing.htm&url=http://www.timken.comhttp://www.howstuffworks.com/framed.htm?parent=bearing.htm&url=http://www.timken.comhttp://www.howstuffworks.com/framed.htm?parent=bearing.htm&url=http://www.timken.comhttp://www.howstuffworks.com/framed.htm?parent=bearing.htm&url=http://www.timken.comhttp://www.howstuffworks.com/hard-disk.htm


3/22


4/22

COOPER BEAR!"#Fixed type bearings (GR)

The outer race of the fixed (GR) bearing has shoulders integral with the roller track, while the inner race assembly

performs the same function by means of hardened shoulders on the clamping rings or similar integral shoulders.

The prime purpose of this type of bearing is to axially locate the rotating portions of the machinery or equipment taking

radial and thrust loads.

The inner race hales are accurately aligned by means of fitted clamping rings.

GR bearing (D type)

!" and !# $eries through "#%&'!!mm shaft sie and!' $eries through %&"**mm shaft sie.

GR bearing (C type)

!" and !# $eries oer "#%&'!!mm shaft sie and !'$eries oer %&"**mm shaft sie.

Expansion type bearings (E)

The expansion (+) bearing has a plain outer race roller track.This bearing takes radial load only.

The inner race is clamped to the shaft, moes and axially when expansion or contraction occurs.

The -ooper expansion bearing offers irtually no resistance to axial moement as the rollers spiral across a flat section

outer race

E bearing (D type)!" and !# $eries through "#%&'!!mm shaft sie and

!' $eries through %&"**mm shaft sie.

E bearing (C type)!" and !# $eries oer "#%&'!!mm shaft sie and !'

$eries oer %&"**mm shaft sie.


5/22

E$a%ples of so%e other bearings

&eep "roove (Conrad) Ball Bearings

Typical bearing manufacturing series numbers used by'.S. (otors range from 'to'*.

&eep groove ball bearings are available in open type bearings+ shielded bearings (single or double)+ and

sealed bearings, Open type conrad bearings+ which are supplied on e$plosion proof -. fra%es and

higher and O&P/TE0C * fra%es and higher+ re1uire bearing caps to contain grease in the housing,

#hielded bearings+ supplied on all -* fra%es (O&P/TE0C through 2' fra%e and on all auto%otive

duty)+ can be used on %otors without bearing caps, #ealed bearings+ which are 3lubed for life3+ possess areduced speed li%it due to seal friction, These sealed bearings are supplied for custo%er specials only,

&ouble Row Angular Ball Bearings


6/22

&ouble row angular ball bearings are very si%ilar to single row conrad bearings+ with the addition of an

e$tra row of balls, Because of this addition+ these double row bearings can handle larger radial and a$ial

loads than conrad bearings, &ouble row angular ball bearings+ available open+ shielded+ or sealed+ are

provided on both hori4ontal and vertical close5coupled pu%ps+ and on larger nor%al thrust %otors as

thrust bearings, #i4es larger than 62-' are not readily available,

Cylindrical Roller Bearings

Typicalbearing manufacturing series numbers used by'.S. (otors are preceded by an )*). +or eample-

*// or *'//.

Cylindrical roller bearings are used on hori4ontal %otors where high radial loads are present, Although

e1uivalent in si4e to conrad ball bearings+ cylindrical bearings have a lower speed li%it and are only

available as open type bearings, These bearings are not available for direct connected %otors+ and are

provided upon special order only on %otors with an overhung load,

#pherical Roller Radial Bearings

Typicalbearing manufacturing series numbers used by'.S. (otors range from +to *+6.

#pherical roller radial bearings are used on hori4ontal %otors which possess an e$tre%ely high radial

load+ or on %otors which re1uire an e$tended bearing life, Typically+ these bearings are wider than

conrad ball bearings+ thus %a7ing special engineering %ore difficult, n addition+ they have a lower speed

li%it than cylindrical roller bearings, #pherical roller radial bearings cannot withstand a$ial loading,

Angular Contact Ball Bearings


7/22

Typical bearing manufacturing series numbers used by

'.S. (otors range from 8to 8*,

Angular contact ball bearings are supplied on vertical %otors only, 9igh thrust vertical %otors using

single angular contact bearings are capable of continuous thrust in only one direction, :ultiple angular

contact ball bearings can be %ounted either bac75to5bac7 for up/down thrust+ or in tande% sets of two or

%ore bearings for e$tra high thrust loading,

#pherical Roller Thrust Bearings

Typical bearing manufacturing series numbers used by'.S. (otors range from ;+2to;+*.

#pherical roller thrust bearings are supplied on vertical %otors only, These bearings can supporte$tre%ely high thrust loads (up to 2< of standard thrust capacity) and %oderate radial loads, Preload

springs are re1uired to supply %ini%u% downthrust to bearings at start up in order to prevent bearing

s7idding, n addition+ the %otor re1uires %ini%u% downthrust at all ti%es to co%press preload springs

and unload the lower guide bearing for %a$i%u% life, =ater cooling is generally re1uired,

Types of Fits


8/22

Depending on the mutual position o tolerance zones o the coupled parts, 3 types o ft can be distinguished:

A. Clearance ft

B. ransition ft

C. !ntererence ft

!" Clearan#e fit"n this type of fit, the sie limits for mating parts are so selected that clearance between them always occur. t may be notedthat in a clearance fit, the tolerance one of the hole is entirely aboe the tolerance one of the shaft. n a clearance fit, the difference betweenthe minimum sie of the hole and the maximum sie of the shaft is known as minimum clearance whereas the difference between the maximumsie of the hole and minimum sie of the shaft is called maximum clearance. The clearance fits may be slide fit, easy sliding fit, running fit, slackrunning fit and loose running fit.

$" %nterferen#e fit"n this type of fit, the sie limits for the mating parts are so selected that interference between them always occur. t may benoted that in an interference fit, the tolerance one of the hole is entirely below the tolerance one of the shaft. n an interference fit, thedifference between the maximum sie of the hole and the minimum sie of the shaft is known as minimum interference, whereas the differencebetween the minimum sie of the hole and the maximum sie of the shaft is called maximum interference. The interference fits may be shrinkfit, heay drie fit and light drie fit.

&" Transition fit" n this type of fit, the sie limits for the mating parts are so selected that either a clearance or interference may occurdepending upon the actual sie of the mating parts. t may be noted that in a transition fit, the tolerance ones of hole and shaft oerlap. Thetransition fits may be force fit, tight fit and push fit.

TYPES OF HAMMERS


9/22

% wide range of )ammers are available, varying in shape, si*e and weight. The different styles reflect different uses.%round the house, the average diy+er only really needs one or two type.

The shape of )ammer heads has not changed much over the years although some modern materials are now used inboth the head and handle. Traditionally handle were made of wood fixed through a hole in the head; this allowed thehandle to be easily replaced if reuired. &odern hammers use modern materials and the handles are often built intothe head - often with a form of built-in shoc# absorber to ma#e them easier to use.

Claw HammerThe most popular hammer for general wor#, available with a wooden often hic#ory, glass-fibre or steel handle; with

or without rubber grip. The most popular weights are $''-(01g 2( to 3$o*. The claw is normally curved, andincorporates a +4+ cut-out to draw nails from timber. The claw can be used to lever up floorboards or where otherplaces where a lever is reuired; care must be ta#en especially with cheaper models as the force applied can easilywea#en the 5oint between the handle and the head.

Ball Pein6ormally used by engineer+s, the pein in this case, is rounded and is usually used for shaping metal and closing rivets.Ball pein hammers are available from '' - 2211 $ o* up to 3 lb., 221 - 2('g 0o* 23o* are the most suitable forgeneral use. )andles are normally wood, usually %sh or )ic#ory.

Cross and Straight Pein%gain, mainly used for shaping metal, the pein can be at right angles to the handle or parallel with it. The most usefuldomestically is the cross pein, where the pein can be used for starting panel pins and tac#s. )andles are normallywood, usually %sh.

Cross Pein Pin Hammer% lighter version of the "ross and 7traight 8ein hammer, ideal for light 5oinery and cabinet wor#. 9eight ''g $o*.

Club Hammer7ometimes called a :ump )ammer, it has a double faced head, and is useful for light demolition wor#, driving steelchisels and masonry nails. %s debris is li#ely to fly, the wearing of safety glasses and wor#ing gloves is recommended.9eight 22'g 3 2/3 lb being best suited to domestic wor#. )andles are normally wood, usually )ic#ory, or syntheticresin.


10/22

Sledge Hammer


11/22

Adice for using hammers

%lways use the right hammer for the 5ob, it will ma#e the 5ob easier and avoid possible damage to thehammer/wor#piece.

6ever hit nails with the side of a chec# or a hammer head. The metal at these points is not hardened as the stri#ingface and could be damaged.

9hen assembling delicate wor#, use a piece of scrap wood between the wor# piece and the head of the hammer. Thiswill prevent damage to the wor#piece.


12/22

TYPES OF METAL WORKING CHISELS

The cold chisel

The metalworker may use a chisel for chipping, grooing, or for shearing. The cold or flat chisel is used for chipping andsometimes for shearing off metal. n shearing, the metal is first clamped in the ise. The chisel is then held so that itsbeel rests on the /aw of the ise and its cutting edge touches the metal at an angle of about 0* degrees. 1hen the chiselis struck, it acts like one scissor blade while the rear /aw of the ise takes the place of the other blade. 2etal can be easilycut this way.

n chipping, the chisel is held similarly, but the beel rests on the surface being cut, blows are sharper, and goggles areworn for protection against flying chips. 3igure "40 shows the flat chisel and its two companions, the diamond4pointchisel and the cape chisel. The 54chisel is not shown, but it is similar to the diamond4point except that its face, instead ofbeing diamond shaped, is cured to form a 5. t is used for grooing.

The diamond4point chisel is used to cut a 54shaped grooe. .t can be used to open a crack in a casting in preparation forwelding. $ometimes, when a part is to be taken off a casting, instead of sawing it off it is grooed with a diamond4pointchisel and then broken off with a hammer or sledge blow.

The cape chisel

The cape chisel is used for cutting rectangular grooes such as keyways. ts cutting edge is made wider than the stockimmediately behind it to gie clearance to the edge. 1ithout this clearance it would bind in the grooe as it cut.

-hisels can be made or dressed and ground to manydifferent shapes to meet special conditions, but the samegeneral principles are followed as those which apply to thethree described.

The head of a well4made chisel is tapered off toward the facewhich receies the hammer blow. This is done to reduce thetendency of the head to spread, or mushroom, from repeatedhammer blows. 6 chisel that has mushroomed should not beused.

Sharpening a chisel

The grinding and whetting of a chisel is done in the same manner as for the plane iron. 7eep in mind that the angle of thebeel differs in some cases from those of the plane iron. The whetting angle of a chisel is * degrees more than that of thebeel angle.

$afety in using the chisel. The chisel is one of the most dangerous hand tools that the worker uses, and care must betaken to follow certain rules of safety. 1hen using a chisel keep both hands on it and keep the fingers away from thecutting edge of the blade.

2ake certain that the material to be cut is held securely in the ise or held by means of a hand screw or -4clamp to thetop of the bench. 8eer begin a chisel operation until the stock is secure. f it is necessary to remoe a piece of stock fromthe ise or to remoe a clamp that is holding the stock, put the chisel down on the bench.


13/22

The only time a chisel should be held with one hand is when a mallet is used to drie it. 1hen cutting with a chisel alwayscut away from yourself. f you carry a chisel around the shop, keep the cutting edge down so that no one walks into it. fthese precautions are followed, there will be little danger of a person9s being cut by a chisel.

Wa! are "a#$es%

0alves are mechanical devices that control the flow and pressure within a system or process. They are essential

components of a piping system that conveys liuids, gases, vapors, slurries etc..1ifferent types of 0alves are available- gate, globe, plug, ball, butterfly, check, diaphragm, pinch, pressure

relief, and control 0alves. 2ach of these types has a number of models, each with different features and

functional capabilities. Some 0alves are self$operated while others manually or with an actuator or pneumatic or

hydraulic is operated.

+unctions from 0alves are-

"topping and starting #o$ %educe or increase a #o$

Controlling the direction o #o$

%egulating a #o$ or process pressure

%elie&e a pipe system o a certain pressure

There are many 0alve designs, types and models, with a wide range of industrial applications. #ll satisfy one or

more of the functions identified above. 0alves are epensive items, and it is important that a correct 0alve is

specified for the function, and must be constructed of the correct material for the process liuid.

C#assi&'a!ion of "a#$es

The following are some of the commonly used 0alve classifications, based on mechanical motion-

'inear (otion )al&es. he )al&es in $hich the closure member, as in gate, globe,diaphragm, pinch, and lit Chec* )al&es, mo&es in a straight line to allo$, stop, or throttlethe #o$.

%otary (otion )al&es. +hen the )al&eclosure member tra&els along an angular or circularpath, as in butter#y, ball, plug, eccentric and "$ing Chec* )al&es, the )al&es are calledrotary motion )al&es.

-uarter urn )al&es. "ome rotary motion )al&es reuire appro/imately a uarter turn, 0through 102, motion o the stem to go to ully open rom a ully closed position or &ice

&ersa.


14/22

C#assi&'a!ion of "a#$es base( on Mo!ion

0alve Types %inear (otion !otary (otion 3uarter Turn

4ate 52S *6 *6

4lobe 52S *6 *6

Plug *6 52S 52S

Ball *6 52S 52S

Butterfly *6 52S 52S

Swing Check *6 52S *6

1iaphragm 52S *6 *6

Pinch 52S *6 *6

Safety 52S *6 *6

!elief 52S *6 *6

C#ass Ra!ings

Pressure$temperature ratings of 0alves are designated by class numbers. #S(2 B78.9:, 0alves$+langed,Threaded, and ;elding 2nd is one of the most widely used 0alve standards. It defines three types of classes-

standard, special, and limited. #S(2 B78.9: covers Class 7==, 7


15/22

# Bonnet acts as a cover on the 0alve body, is cast or forged of the same material as the body. It is commonly

connected to the body by a threaded, bolted, or welded ?oint. 1uring manufacture of the 0alve, the internalcomponents, such as stem, disk and actuator, are put into the body and then the Bonnet is attached to hold all

parts together inside.

"a#$e Tri*

0alve@s trim is a collective name for the replaceable parts, in a 0alve. # typically 0alve design includes a disk,

seat, stem, and sleeves needed to guide the stem.

"a#$e +is,

The disc is the part which allows, throttles, or stops flow, depending on its position. In the case of a plug or a

Ball 0alve, the disc is called plug or a ball. The disk is the third most important primary pressure boundary.

;ith the 0alve closed, full system pressure is applied across the disk, and for this reason, the disk is a pressurerelated component.

1isks are usually forged, and in some designs, hard surfaced to provide good wear properties. (ost 0alves are

named, the design of their disks.

"a#$e Sea!-s.

# 0alve may have one or more seats. In the case of a globe or a swing$Check 0alve, there is usually one seat,which forms a seal with the disc to stop the flow. In the case of a 4ate 0alve, there are two seatsA one on the

upstream side and the other on the downstream side. # 4ate 0alve disc has two seating surfaces that come in

contact with the 0alve seats to form a seal for stopping the flow.

The seat ensure the seating surface for the disk. +or a good sealing, a fine surface finish from the seating area isnecessary.

In some designs, the body is machined to serve as the seating surface, in other designs, forged seal rings are

threaded or welded to the body.

To improve the wear resistance of the seat or seal rings, the surface is often hard faced.

"a#$e S!e*

The 0alve stem provides the necessary movement to the disc, plug or the ball for opening or closing the 0alve,

and is responsible for the proper positioning of the disk. It is connected to the 0alve handwheel, actuator, or thelever at one end and on the other side to the 0alve disc. In gate or 4lobe 0alves, linear motion of the disc is

needed to open or close the 0alve, while in plug, ball and Butterfly 0alves, the disc is rotated to open or close

the 0alve.


16/22

Stems are usually forged, and connected to the disk by threaded or other techniues. To prevent leakage, in the

area of the seal, a fine surface finish of the stem is necessary.

There are five types of 0alve stems-

Rising S!e* /i! O0!si(e S're/ an( Yo,ehe e/terior o the stem is threaded, $hile the portion o the stem in the )al&e is smooth.he stem threads are isolated rom the #o$ medium by the stem pac*ing. $o dierentstyles o these designs are a&ailable4 one $ith the hand$heel attached to the stem, sothey can rise together, and the other $ith a threaded slee&e that causes the stem to risethrough the hand$heel. his type o )al&e is indicated by 56. ". 7 8.5 is a common designor N9" and larger )al&es.

Rising S!e* /i! Insi(e S're/he threaded part o the stem is inside the )al&e body, and the stem pac*ing along thesmooth section that is e/posed to the atmosphere outside. !n this case, the stem threadsare in contact $ith the #o$ medium. +hen rotated, the stem and the hand$heel to risetogether to open the )al&e.

NonRising S!e* /i! Insi(e S're/he threaded part o the stem is inside the )al&e and does not rise. he )al&e disc tra&elsalong the stem, li*e a nut i the stem is rotated. "tem threads are e/posed to the #o$medium, and as such, are sub;ected to the impact. hat is $hy this model is used $henspace is limited to allo$ linear mo&ement, and the #o$ medium does not cause erosion,corrosion or abrasion o the stem material.

S#i(ing S!e*his )al&e stem does not rotate or turn. !t slides in and out the )al&e to open or close the)al&e. his design is used in handoperated le&er rapid opening )al&es. !t is also used incontrol )al&es are operated by hydraulic or pneumatic cylinders.

Ro!ary S!e*his is a commonly used model in ball, plug, and Butter#y )al&es. A uarterturn motion othe stem open or close the )al&e.

In the main (enu )0alves) you will find some links to detailed large images of !ising and *6* !ising Stem

0alves.

"a#$e S!e* Pa',ing

+or a reliable seal between the stem and the Bonnet, a gasket is needed. This is called a Packing, and it is fitted

with e.g. the following components-

ng bo/.

. =land, a *ind o bushing, $hich compressed de pac*ing into the stu>ng bo/.

3. "tu>ng bo/, a chamber in $hich the pac*ing is compressed.

?. 9ac*ing, a&ailable in se&eral materials, li*e e#on@, elastomeric material, fbrous materialetc..


17/22

. A bac*seat is a seating arrangement inside the Bonnet. !t pro&ides a seal bet$een thestem and Bonnet and pre&ents system pressure rom building against the )al&e pa**ing,$hen the )al&e is ully open. Bac* seats are oten applied in =lobe )al&es.

#n important aspect of the life time of a 0alve is the sealing assembly. #lmost all 0alves, like standard Ball,

4lobe, 4ate, Plug and Butterfly 0alves have their sealing assembly based upon shear force, friction and tearing.

Therefore 0alve packaging must be properly happen, to prevent damage to the stem and fluid or gas loss. ;hena packing is too loose, the 0alve will leak. If the packing is too tight, it will affect the movement and possible

damage to the stem.

Typical sealing assembly

-, 4land +ollover ,4land 2,Stuffing Bo with Packing *,Back Seat

"a#$e Yo,e# 5oke connects the 0alve body or Bonnet with the actuating mechanism. The top of the 5oke holding a 5okenut, stem nut, or 5oke bushing and the 0alve stem passes through it. # 5oke usually has openings to allow

access to the stuffing bo, actuator links, etc.. Structurally, a 5oke must be strong enough to withstand forces,

moments, and torue developed by the actuator.

"a#$e Yo,e N0!# 5oke nut is an internally threaded nut and is placed in the top of a 5oke by which the stem passes. In a 4ate

0alve e.g., the 5oke nut is turned and the stem travels up or down. In the case of 4lobe 0alves, the nut is fiedand the stem is rotated through it.

"a#$e A'!0a!or"and$operated 0alves are usually euipped with a handwheel attached to the 0alve@s stem or 5oke nut which isrotated clockwise orcounter clockwise to close or open a 0alve. 4lobe and 4ate 0alves are opened and closed in

this way. "and$operated, uarter turn 0alves, such as Ball, Plug or Butterfly, has a lever for actuate the 0alve.


18/22

There are applications where it is not possible or desirable, to actuate the 0alve manually by handwheel or lever

These applications include- 'arge )al&es that must be operated against high hydrostatic pressure )al&es they must be operated rom a remote location +hen the time or opening, closing, throttle or manually controlling the )al&e is longer,

than reuired by systemdesign criteria

These 0alves are usually euipped with an actuator.#n actuator in the broadest definition is a device that produces linear and rotary motion of a source of power

under the action of a source of control.

Basic actuators are used to fully open or fully close a 0alve. #ctuators for controlling or regulating 0alves aregiven a positioning signal to move to any intermediate position. There a many different types of actuators, but

the following are some of the commonly used 0alve actuators- =ear Actuators lectric (otor Actuators 9neumatic Actuators ydraulic Actuators "olenoid Actuators

#aunders =eir Type A &iaphrag% >alveThe original Saunders ;eir Type general purpose diaphragmvalve offers smooth flow and simple operation in any position.

Its design provides tight shut$off and ecellent flow controlcharacteristics. 6ffered in a wide selection of body materials,

linings, diaphragms, and operators.

#aunders Type ?B #traight Thru &iaphrag% >alveThe Straight Thru diaphragm valve design handles abrasive and

corrosive slurries, thick coagulating fluids, and a wide variety ofsuspended solid materials. The straight, full open bore designfacilitates cleanout rods, brushes and )pigs).

+iaprag* $a#$e

&iaphrag% valvesor membrane valves consists of avalvebody with two or more ports, a diaphragm, and a

)saddle) or seat upon which the diaphragm closes the valve. The valve is constructed from eitherplasticor

steel.

6riginally, the diaphragm valve was developed for use in non$hygienicapplications. %ater on the design was

adapted for use in the bio$pharmaceutical industry by using compliant materialsthat can withstand saniti&ing

and sterili&ing methods.

There are two main categories of diaphragm valves- one type seals over a ) weir) saddle and the othersometimes called a )straight$way) valve seals over a seat. The saddle type is the most common in process
http://www.ask.com/wiki/Valve?qsrc=3044http://www.ask.com/wiki/Valve?qsrc=3044http://www.ask.com/wiki/Plastic?qsrc=3044http://www.ask.com/wiki/Steel?qsrc=3044http://www.ask.com/wiki/Hygienic?qsrc=3044http://www.ask.com/wiki/Materials?qsrc=3044http://www.ask.com/wiki/Materials?qsrc=3044http://www.ask.com/wiki/Weir?qsrc=3044http://www.ask.com/wiki/Valve?qsrc=3044http://www.ask.com/wiki/Plastic?qsrc=3044http://www.ask.com/wiki/Steel?qsrc=3044http://www.ask.com/wiki/Hygienic?qsrc=3044http://www.ask.com/wiki/Materials?qsrc=3044http://www.ask.com/wiki/Weir?qsrc=3044


19/22

applications and the seat$type is more commonly used as a tank bottom valve but eists also as a process valve.

;hile diaphragm valves usually come in two$port forms D$way diaphragm valve, they can also come withthree ports 9D$way diaphragm valves also called t$valves and more so called block$valves. ;hen more than

three ports are included, they generally reuire more than one diaphragm seatA however, special dual actuators

can handle more ports with one membrane.

1iaphragm valves can be manual or automated. Their application is generally as shut$off valves in processsystems within the food and beverage,pharmaceuticalandbiotechindustries. The older generation of these

valves is not suited for regulating and controlling process flows, however newer developments in this area have

successfully tackled this problem.

In addition to the well known, two way shut off diaphragm valve, other types include- three way &ero deadlegvalve, sterileaccess port, block and bleed, valbow and tank bottom valve ?ust to name a few.

The Actuator

;hile a wide variety of materials and part shapes are available, diaphragm valves use the same basic

mechanism. # solid, movable piece the )actuator) presses into the middle of a thick yet fleible barrier the

)diaphragm), forcing material into the conduit and blocking the flow of liuids. The actuator consists of a wideloop or disk on top of the valve. #t the center of the disk is a threaded rod that enters the valve and attached to

the )head) piece, right above the diaphragm. 2ssentially a screw, the threaded rod moves up and down in its

housing as the disk is turned counterclockwise and clockwise, respectively. The large diameter of the diskallows the user to generate considerable leverageDtorue. Therefore, even at high pressures, pipes can be shut off

with enough work from the user. *ote- there are also actuator designs where, instead of a manual control, the

position of the head is controlled by hydraulic press or pneumatic tool.

The shape of the actuator head corresponds to the si&e and shape of the pipe inside the valve. +or )#)$typevalves, the pipe narrows to a small gap right below the diaphragm. #s such, the head consists of a shallow

wedge. )EB)$type valves feature a full$si&ed pipe diameter, reuiring the head to be a tall, slab with gently

sloping edgesA this allows the head to distribute pressure across a large area of the diaphragm. +inally, );+B)$type valves have a wedge$like head that, in addition to suee&ing the pipe closed, can )pull) the diaphragm up

beyond the normal diameter to increase flow.

The Diaphragm

1urable and thick, the purpose of the diaphragm is to protect the material inside the valve from the contents of

the pipe. +or eample, in a chemical manufacturing facility that producing hydrofluoric acid which dissolvesvirtually every substance ecept for certain plastics, a special diaphragm would seal the metal actuator head

and valve housing. 6therwise, the acid could melt the actuator, burst from the pipe to kill workers and surge

uncontrollably.

2ither riveted to the ceiling of the pipe or suee&ed along the edges between two stacked pieces, the diaphragmis flat when at rest. The center is considerably thicker and often reinforced with mesh fibers. (eanwhile, the

edges are thinner for easier stretching.

Conduit Shape

The shape of the valve@s conduit i.e. the cross section has important ramifications on the pressure within thepipes downstream. +or eample, the )#)$type@s narrowing conduit slows the flow rate at the valve. This slow

rate is good for abrasives in that it helps protect the interior of the pipe. In the same way, the );+B)$type works

well for hydrants in that the narrow conduit allows for hoses to fill as a controlled rate, preventing the )whip$
http://www.ask.com/wiki/Biological_membrane?qsrc=3044http://www.ask.com/wiki/Pharmaceutical?qsrc=3044http://www.ask.com/wiki/Pharmaceutical?qsrc=3044http://www.ask.com/wiki/Biotech?qsrc=3044http://www.ask.com/wiki/Biotech?qsrc=3044http://www.ask.com/wiki/Sterilization_(microbiology)?qsrc=3044http://www.ask.com/wiki/Sterilization_(microbiology)?qsrc=3044http://www.ask.com/wiki/Biological_membrane?qsrc=3044http://www.ask.com/wiki/Pharmaceutical?qsrc=3044http://www.ask.com/wiki/Biotech?qsrc=3044http://www.ask.com/wiki/Sterilization_(microbiology)?qsrc=3044


20/22

cracking) effect caused by the rapid epansion of a flat, folded tube. 6nce the water has displaced all the air in

the hose, however, the conduit can be epanded to increase the flow of water. This increases the pressure at theno&&le of the hose, allowing water to shoot farther.

+inally, the )EB)$type@s large conduit opening pairs the high$speed, high$volume flow of a regular pipe with the

convenience and safety of an emergency sto

Ga!e $a#$e

The gate valve, also known as a sluice valve, is avalvethat opens by lifting a round or rectangular gateDwedgeout of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces between the gate and seats

are planar, so gate valves are often used when a straight$line flow of fluid and minimum restriction is desired.

The gate faces can form a wedge shape or they can be parallel. 4ate valves are primarily used to permit orprevent the flow of liuids, but typical gate valves shouldn@t be used for regulating flow, unless they are

specifically designed for that purpose. Because of their ability to cut through liuids, gate valves are often used

in thepetroleumindustry. +or etremely thick fluids, a specialty valve often known as a 7nife valveis used tocut through the liuidF7G. 6n opening the gate valve, the flow path is enlarged in a highly nonlinear manner with

respect to percent of opening. This means that flow rate does not change evenly with stem travel. #lso, a

partially open gate disk tends to vibrate from the fluid flow. (ost of the flow change occurs near shutoff with a

relatively high fluid velocity causing disk and seat wear and eventual leakage if used to regulate flow. Typicalgate valves are designed to be fully opened or closed.FG;hen fully open, the typical gate valve has no

obstruction in the flow path, resulting in very low frictionloss.F9G

4ate valves are characterised as having either a rising or a nonrising stem. !ising stems provide a visual

indication of valve position because the stem is attached to the gate such that the gate and stem rise and lowertogether as the valve is operated. *onrising stem valves may have a pointer threaded onto the upper end of the

stem to indicate valve position, since the gate travels up or down the stem on the threads without raising orlowering the stem. *onrising stems are used underground or where vertical space is limited.

Bonnets provide leakproof closure for the valve body. 4ate valves may have a screw$in, union, or bolted

bonnet. Screw$in bonnet is the simplest, offering a durable, pressure$tight seal. 'nion bonnet is suitable for

applications reuiring freuent inspection and cleaning. It also gives the body added strength. Bolted bonnet is

used for larger valves and higher pressure applications.

#nother type of bonnet construction in a gate valve is pressure seal bonnet. This construction is adopted for

valves for high pressure service, typically in ecess of 7


21/22

Types of !oo#s

C#eaning !oo#s Broom Brush Eeather duster Eloor buer ata*i !ce resuracer (op

(op buc*et cart 6>ce cleaning cart 9ipe cleaner 9ressure $asher "ponge "ueegee

"team mop a$ashi )acuum cleaner

C0!!ing an( abrasi$e !oo#s Blade Bolt cutter Broach Ceramic tile cutter Chisel Coping

sa$ Countersin* Diamond blade Diamond tool Dra$ *nie Drill bit mery cloth Eile

Eretsa$ Eroe =lass cutter =rater =rinding $heel and sa$ Fnie (iter sa$ Nail clipper

9ipecutter 9lane %asp %azor %eamer "andpaper "a$ "calpel "cissors "teel $ool "urorm "$itchblade Gtility *nie +ater ;et cutter +ire brush +ire cutter +ire stripper

Gar(en !oo#s Adze A/e Billhoo* Bo$ sa$ Chainsa$ Culti&ator arth auger dger

=arden or* =arden hose =arden tro$el atchet edge trimmer oe ori hori !rrigation

sprin*ler 'a$n aerator 'a$n mo$er 'a$n s$eeper 'ea blo$er 'oppers 'oy (achete

(attoc* 9ic*a/e 9itchor* 9lough Hplo$I 9ost hole digger 9runing shears HsecateursI %a*e

%oller %otary tiller "cythe "ho&el "ic*le "lasher "pade "plitting maul "tring trimmer

Han( !oo#s Bloc* plane BNC inserterJremo&er Brace Brada$l Brea*er bar Card scraper

CatKs pa$ Caul*ing gun Clamp Crimping pliers Cro$bar =rease gun Eish tape ammer

and truc* a$* e/ *ey Lac* 'ug $rench 'oc*ing pliers (allet (itre bo/ (on*ey$rench Nut dri&er 9aint roller 9aintbrush 9ipe $rench 9liers 9lumberKs sna*e 9lunger

9unch 9unch do$n tool 9utty *nie %atchet "in* $rench "cratch a$l "cre$dri&er

"ledgehammer "oc*et $rench "pi*e maul "taple gun "titching a$l "trap $rench ire iron

orue $rench ro$el Gpholstery hammer +rench HspannerI

Ma'ine an( *e!a#/or,ing !oo#s Automatic lathe Ballpeen hammer Broaching machine

Drill press ndmill nglish $heel =ear shaper =rinding machine ac*sa$ obbing

machine Lig borer 'athe (etal$or*ing lathe (illing cutter (illing machine 9laner 9lasma

cutter "cre$ machine "haper ap and die hread restorer ool bit urret lathe +elder

Meas0ring an( a#ign*en! !oo#s ArchitectKs scale Beam compass Caliper Chal* bo/ Compass ngineerKs scale Ele/ible cur&e Lig 'aser le&el 'aser line le&el 'aser measuring

tool (icrometer 9lumbbob 9rotractor %uler "cale "liding be&el "pirit le&el "uare

"traightedge ape measure emplate

Po/er !oo#s Angle grinder Bandsa$ Belt sander Blo$ torch Chop sa$ Circular sa$

Concrete sa$ Crusher Cutting torch Die grinder Drill =lue gun eat gun !mpact $rench

Lac*hammer Ligsa$ Lointer Nail gun Needlegun scaler 9o$er tro$el %adial arm sa$

%andom orbital sander %eciprocating sa$ %otary tool %outer table "ander "croll sa$


22/22

"oldering gun "oldering iron "team bo/ able sa$ hic*ness planer +ood router +ood

shaper

Notes on Fitting -2

Documents

Transcript of Notes on Fitting -2