Rubber Gate Seals - · PDF fileGENERAL Rubber Gate seals are manufactured from specially formulated rubber compounds giving high abrasion resistance, ﬂexibility and eﬃcient sealing

RubberGate Seals

RubberGate Seals

676537792ISO 9001 : 2008

GENERAL Rubber Gate seals are manufactured from specially formulated rubber compounds giving high abrasion resistance, flexibility and efficient sealing. The high flexibility of Rubber Gate seals results in overcoming inaccuracies due to allowable tolerances of construction, fabrication and erection of Gate / guide plates. The gate seal accommodates itself to the normal variations arising from thermal expansion / contraction, load deflections, etc., ensuring adequate and effective sealing.

Rubber Gate seals are manufactured for all applications in the widest range of types, shapes and sizes catering to the

requirements of all Irrigation and Hydro‐electric Projects.

TYPES Plain Type

Brass / Stainless Steel Cladded

Abrasion Resistant Fluorocarbon ( PTFE / Teflon®) Cladded

PLAIN RUBBER SEALS These are available in all standard shapes and sizes viz., Flat Type, `P /`J /Musical Note Type, Double Stem Type, Double

Bulb Type, `L /`Z Type and special section seals.

METAL CLADDED RUBBER SEALS Rubber Seals are metal cladded to reduce the friction during gate operation. Metal cladding also reduces and checks

the tendency of rubber bulb to extrude in available spaces or gaps due to high water pressure during opening and

closing of gate. The rigidity of metal cladding however, reduces the flexibility of the seal as compared to plain rubber

seals or Fluorocarbon Film cladded rubber seals. Metal cladding may have center or edge slotting to reduce rigidity.

Thickness of metal cladding normally provided is 1.5 mm to 3.0 mm. Metal cladded seals are manufactured in Brass,

Bronze or Stainless Steel.

FLUOROCARBON FILM CLADDED RUBBER SEALS Fluorocarbon Film Cladded Seals offer the advantage of extremely low coefficient of friction. The Fluorocarbon Film is

moulded along with the rubber component of the gate seal making it an integral part of the seal. The Fluorocarbon Film

does not project above the bulb surface since it is recessed into the rubber as it is with metal cladding. The high

flexibility of specially formulated rubber compound of gate seal and the extremely low coefficient of friction of

fluorocarbon film results in substantial reduction of frictional load, and thereby, hoists of reduced capacity can be used.

Fluorocarbon Film Cladded Rubber Gate Seals should never be bent or skewed during storage, transportation and

erection. They should preferably be transported on wooden planks or by using similar methods to keep the cladding

straight. Bending or skewing in not a method to test the bond strength.

Dam Gate Seals

Professionals in polymer application technology

MANUFACTURING PROCESS Rubber Gate seals are manufactured by two manufacturing processes viz., extrusion and moulding.

EXTRUSION: Extrusion is the cheapest method of manufacture of rubber gate seals. Expensive moulds are not required. However,

close tolerances are difficult to maintain. Maintaining uniform cross section throughout the length of the gate seal is

difficult to achieve thereby, non uniform pre‐compression of the gate seals is observed. Cladded gate seals cannot be

manufactured by this process.

MOULDING: Rubber gate seals are manufactured in moulds whereby, a uniform cross section through out the length of the gate seal

is attained. Close tolerances can be achieved by this process. There is better control over the quality and size of the

gate seal.

SHAPES Rubber Gate seals are available in the widest range of shapes. Since every Irrigation / Hydroelectric Project has its own

design requirements, if the shape required does not fall in the existing range, gate seals of special sections as per the

customer s specifications are also manufactured.

Flat Type ‐ – Rectangular

– Half round at one end

– Wedge Type

`P /`J /Musical Note Type* – Solid Bulb

– Hollow Bulb

Double Stem Type* – Solid Bulb

– Hollow Bulb

Double Bulb Type* – Solid Bulb

– Hollow Bulb

`L /`Z Type Seals

Special Section Seals

* Corner Seals

‐ 2 Dimensional

‐ 3 Dimensional

( * indicates with / without cladding)


Dam Gate Seals

GATESEAL SPECIFICATIONS

AS PER INDIAN STANDARDS IS: 11855:1986

RUBBER:

Hardness : Shore `A : 65 ± 5

Tensile Strength : N/mm2 : 14.5

Elongation at Break : % : 450

Water Absorption : % by wt. : < 10%

Oxygen Ageing : : > 80% of value of Tensile strength before ageing

RUBBER ‐ METAL ADHESION TEST:

Tensile Strength : N/cm : 176

RUBBER ‐ FLUOROCARBON FILM ADHESION TEST:

Tensile Strength : N/cm : 54

INTERNATIONAL STANDARDS ASTM RUBBER:

Hardness : Shore `A : 65 ± 5

Tensile Strength : lb/in2 : 3000

Elongation at Break : % : 450

minimum Water Absorption : % by wt. : < 5

Compression set : % : 30 maximum

Oxygen Ageing : % : > 80% of value of Tensile strength before ageing

FLUOROCARBON FILM:

Tensile Strength : psi : 2000

Elongation at Break : % : 250 minimum

RUBBER ‐ METAL ADHESION TEST:

Tensile Strength : lb/inch width : 100

RUBBER ‐ FLUOROCARBON FILM ADHESION TEST:

Tensile Strength : lb/inch width : 30


Dam Gate Seals

GATESEAL LENGTHS Plain rubber gate seals are supplied in desired lengths. The essential criteria for deciding the length of such seals is the

weight of the roll, ease in transportation and handling.

Metal cladded rubber seals should not be bent or skewed. Metal cladded rubber seals are supplied in maximum lengths

of 5.0 meters. The limitation being with regard to the maximum lengths that can be accommodated in normal trucks.

Fluorocarbon Film cladded rubber seals cannot be bent or skewed as with metal cladded rubber seals. They are

supplied in either:

a. Maximum straight lengths of 5.0 meters and parts thereof (refer Drg. # AI‐24B). The total desired length of

the gate seal can be made up of such lengths and jointed at site using any of the jointing methods (see `jointing of

rubber gate seals ).

b. Fluorocarbon Film though having the lowest coefficient of friction, has its own limitation. It is a plastic

material having limited modulus of elasticity. Thus, when a Fluorocarbon Film is stretched beyond its elastic limit, severe

localized stress may occur, cannot regain its original dimension and leads to permanent deformation. This limitation is

also applicable to Fluorocarbon Film Cladded Rubber Gate Seals whereby the Fluorocarbon Film and the bonding gets

permanently damaged. In order to overcome this, the total Fluorocarbon cladding length is divided into smaller lengths

with a `non‐fluorocarbon portion of about ½ , comprising of rubber and matching the fluorocarbon film cross section.

When lowering / raising the gate, corner seals are subjected to maximum stress in the complete rubber seal assembly

Corner seals should be single piece moulded type only.

JOINTING OF RUBBER GATESEALS Plain rubber seals are easy to joint. However, with Fluorocarbon Film Cladded seals up to 5.0 meters, it is

imperative to understand the problem associated with it.

Fluorocarbon Film is a non‐stick material and jointed using specialized techniques at the factory. It is virtually

not possible to bond the exposed Fluorocarbon Film section to Fluorocarbon Film at both ends of seal

lengths at site (refer Fig. #1a, Drg. #24A). While attempting to bond such exposed sections, only the rubber

section can be cemented with the fluorocarbon film section thickness unbonded. Leakages occur through

such unbonded fluorocarbon film thickness sections of the seals under medium to high heads. The force

exerted at such minute areas being high enough for fluorocarbon film bonding failure to occur over a period

of time. The problem is overcome by providing a `nonfluorocarbon length of apprx. ½ at the seal ends to

attain a total rubber‐rubber bond (refer Fig. #1b, Drg. #24A). There is no significant increase in the co‐efficient

of friction since the `non‐fluorocarbon length is negligible as compared to the total seal length. All Rubber‐

Rubber joints are stronger, reliable and can be easily executed at site. Additional extra length of rubber

portion is provided for `Shop Trimming at site to achieve the exact desired total seal length.


Dam Gate Seals

Splicing and site jointing of rubber gate seals can be carried out by various methods:

Adhesive splice joint

Vulcanized splice joint

ADHESIVE SPLICE JOINT Adhesive splice joint procedures are adopted at locations where vulcanized splicing is not possible.

All seals to be correctly punched cut to true length and fully fitted to the gate during shop assembly fusing

the gate and clamp plate as templates. All seal joints to be butted up square with no visible gaps or steps in

seal contact faces. On final site assembly, all seal joints are treated with a cyanoacrylate adhesive having

maximum strength with longest open times.

VULCANISED SPLICE JOINT Jointing of rubber seals at the gate fabricator s workshop or at site, vulcanized splice joints give the best

results.

For making vulcanized splice joints, moulds, equipments, tools and rubber raw materials are required. The

jointing is carried out in heated moulds with raw rubber compound used in‐between. Best joint strengths

(almost equal to the original seal) are achievable.

For cladded seal jointing at site, the procedure is the same. The cladding, however, will not be continuous at

the joint. There will be a gap of about 6 to 12 mm between the cladding at the joint. The gap will however

have rubber in between matching the cross section of the seal except for the shrinkage of the fresh rubber

compound. The shrinkage however is very negligible and is accommodated during seal compression

resulting in no leakage.

Rubber gate seals cladded or plain should never be bent at the joints.

Vulcanising equipment complete with vulcanizing press, moulds, rubber compounds, splicing tools etc., are

available.


Dam Gate Seals

Flat Type Rubber Seals


TYPE F1 / F2 / F3 / F4

TYPE F1

A

A

DC

A

B

c

B

B

TYPE F1 / F2 / F3 / F4

TYPE F1 / F2 / F3 / F4

A

A

c

BD

c

BD

A

B

TYPE F1 / F2 / F3 / F4

A

c

BD

T Y P E F 1

A

B

c

TYPE F1 / F2 / F3 / F4

’P’/’J’ Type Rubber Seals


A

DC

B


’L’/’Z’ Type Rubber Seals











Documents

Rubber Gate Seals - · PDF fileGENERAL Rubber Gate seals are manufactured from specially formulated rubber compounds giving high abrasion resistance, ﬂexibility and eﬃcient sealing