Couplings

couplings.jpg (17017 bytes)INTRODUCTION

Glass components are connected with one another by flanged joints. All the glass nozzles have special ends known as buttress ends to fix up a backing flange behind the end and connect the two opposite flanges by bolting with each other.

Coring usually gives tapered buttress ends (GARG type) which are backed by a metal flange with matching tapered bore and with a soft asbestos insert in between to prevent excessive point stresses on the glass surface. These joints give excellent performance when the glass and metal tapers are perfectly matched with full concentricity and when the alignment is perfect. In case of sight imperfection, there is a chance of excessive stresses and breakage of glass neck. Secondly, because of the taper fit, the glass to flange joint is mechanically locked and it is difficult to change flanges. 

We give another type of end which we call collared buttress end. This is similar to stub ends used in copper and stainless steel piping. The collar is backed by an asbestos rope, a metal split ring and a metal backing flange. This type of joint is very strong and has flexibility in case of slight misalignment. The overall dimensions of this type of end are kept same as those of tapered end. Hence it is easy top interchange these types of ends; and even fixing tapered end with collared end is possible. 

The following table gives dimensions of both the types of buttress ends 

Nomial Bore DN 25 40 50 80 100 150 225 300 450 600
Outside Diameter D 33 46 59 87 115 163 238 322 475 640
Inside Diameter D1 26.5 38.5 50 76 104 154 229 308 462 622
Collar Diameter D2 42.5 57.5 70 99.5 133 185 259 341 535 642

FLANGES

These flanges are used to couple a glass ends to glass ends or to a below.Backing flanges are made up of cast iron and are used with inserts.They can normally be supplied in various grades of stainless steel on special order.

Cat Ref DN D1 D2 N x d L L1

GCF 25 25 95 43 51 70 3 x 7 10 6
GCF 40 40 110 58 66 86 3 x 9 10 6
GCF 50 50 120 70 81 98 3 x 9 12 8
GCF 80 80 155 101 112 133 6 x 9 12 9
GCF 100 100 200 134 148 178 6 x 9 12 9
GCF 150 150 275 186 196 254 6 x 9 15 9
GCF 225 225 350 260 282 310 8 x 11 28 7
GCF 300 300 425 342 363 395 12 x 11 34 7
GCF 450 450 630 537 557 585 12 x 14 37 7
GCF 600 600 755 643 690 710 12 x 14 50 5

INSERTS

Two types of inserts are used depending upon the type of buttress ends and the backing flange. 

1. Type A : For tapered buttress ends, asbestos gasket arcs are used for fitting between the tapered end and the flange. 

2. Type B : For collared buttress ends, Cast iron split rings with thin asbestos rope are used & as backing rings between collar and the flange. 

CAT. REF. DN D D1 L

GCNB 25 25 50 32 10
GCNB 40 40 65 48 10
GCNB 50 50 80 60 10
GCNB 80 80 110 88 11
GCNB 100 100 146 117 14
GCNB 150 150 195 165 14
GCNB 225 225 280 240 10
GCNB 300 300 361 324 10
GCNB 450 450 555 480 18
GCNB 600 600 684 642 10

ADAPTOR FLANGES

These flanges are used for coupling the glass components with other equipments or pipe lines. For this purpose, the drillings on the adaptor flanges are as per desired standards namely BS 10 Table E, Table F or ASA 150. For the flanges, specify as follows.

CAT REF. DN H D HDW52A.gif (1348 bytes)
GCFA 1 25 15 115
GCFA 1.5 40 18 150
GCFA 2 50 21 165
GCFA 3 80 24 200
GCFA 4 100 26 220
GCFA 6 150 26 285
GCFA 9 225 29 395
GCFA 12 300 34 445

COMPRESSION SPRINGS

Compression springs are used to set and maintain the correct bolt load on standard glass couplings. Standard compression springs have corrosion resistant coating and are also available in stainless steel.

CORROSION PROTECTED SPRING STEEL

CAT. REF. DN Free Length 
L
Installed Length 
L1

GDF 6.5 15 10.1 8.1
GDF 8.5 25-100 14.5 11.0
GDF 10.5 150-300 22.0 18.0
GDF 13 450-600 28.7 22.7
GDF 13.5 800-1000 45.0 36.0

STAINLESS STEEL

CAT. REF. DN Free Length 
L
Installed Length 
L1
GDF 6.5E 15 12.4 10.4
GDF 8.5E 25-100 18.0 14.5
GDF 10.5E 150-300 28.5 24.5
GDF 13E 450-600 37.3 31.3

PTFE "O" RINGS

They are used as gaskets and sandwiched between buttress ends in glass couplings

CAT. REF. DN D D1 d L

GTR 25 25 62 33 3 5
GTR 40 40 57 48 3 5
GTR 50 50 70 59 3 5
GTR 80 80 100 88 3 5
GTR 100 100 134 119 4 5
GTR 150 150 186 168 4 5
GTR 225 225 260 236 4 5
GTR 300 300 342 318 4 5
GTR 450 450 537 490 6 5
GTR 600 600 686 640 8 10

PTFE BELLOWS

PTFE Bellows are important components in glass piping. They take care of slight misalignment and thermal expansion as well as mechanical stresses. They even absorb vibrations. Hence, they are invariably used in connecting glass components with other non-glass equipments. The PTFE Bellows have built in 'O' Ring and hence no other gasket is required in the use. They can be supplied with split rings and flanges with suitable drillings.

CAT. REF. DN L

GFB 25 25 68
GFB 40 40 68
GFB 50 50 68
GFB 80 80 68
GFB 100 100 68
GFB 150 150 68
GFB 225 225 68
GFB 300 300 68

PTFE VACCUM BELLOWS

These bellows are made stronger to withstand vaccum. Inner sleeves are also supplied for these bellows on special order.

CAT. REF. DN L

GFB 80 80 65
GFB 100 100 65
GFB 150 150 65
GFB 225 225 65
GFB 300 300 65