Utilities

SRJ Snap Ring Joint

The Snap Ring Joint has been developed to overcome the disadvantages of conventional jointing systems in gas and water utilities industry.

srj
Sectors

Utilities

  • OVERVIEW
  • STEEL PIPELINES

OVERVIEW

The Snap Ring Joint is a highly cost-effective alternative to conventional mechanical coupling devices and to welded joints in many applications, in each phase of the life cycle of a gas or water distribution network.

The SRJ has undergone a stringent test regime in order to gain Lloyds Register and ABS Type Approval for use in a variety of applications and has patent protection in over seventy countries worldwide.

While a good weld is full strength and highly ductile, there are occasions where the workmanship may prove questionable. The SRJ eliminates the need to weld service pipes in a gas or water distribution network.

Since the SRJ weighs so much less than a comparable mechanical connection, transport and logistics costs are lower and once on-site, fit-up times are much shorter than for a comparable mechanical connector. Maintenance is made easier since the SRJ is easily dismantled, facilitating pipe inspection and maintenance operations.

STEEL PIPELINES

Managing assets - both new-build and mature infrastructure - in gas and water supply, requires careful decisions about new equipment, replacements and refurbishment.

What may be the cheapest solution at the outset, may prove to be the most expensive when taken in the context of the life cycle of the infrastructure. This is especially true with respect to the operator's health, safety and environmental responsibility.

Water utilities have invested heavily in replacing their water mains over the past 20 years and gas utilities have an extensive programme underway to upgrade their distribution infrastructure, yet they suffer from a persistently high system leakage rate.

For many applications, the SRJ simply eliminates the need to weld service pipes. It does away with coded welders, weld procedures, welder qualifications, prepping, pre-heat, PWHT, NDT and any necessary grinding and re-welding, as well as the welding equipment.

Essential maintenance of the piping that comprises a gas or water distribution network must be carried out with minimal disruption to operations. Any means of reducing the cost of repairs, modifications, upgrades and retrofits, will be keenly sought.

The SRJ can make a tangible contribution to this effort and gives the operator greater flexibility in planning maintenance work and responding to unforeseen circumstances than welded joints.

Fit-up times are shorter than is the case with welded joints. Preparation of pipes and piping components for the SRJ connection (grooving and chamfer cutting, coating, grease covering or capping) can be done in a pre-fabrication workshop or on-site. Both the pre-engineered or on-site machining options are available.

The preparation and installation tool for the SRJ is designed for use by trained fitters and is standard equipment. This ensures joint integrity and keeps costs down. It is pre-calibrated to cut the grooves and offers a strict control of accuracy of measurement, and quality of grooving and chamfer cutting.

Extensive testing has demonstrated its ability to withstand internal design pressure as well as significant bending brought about by stresses in the attached pipework.

Operating Principle and Key Features

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To install the connector (supplied pre-fitted with radial seals), the pipe ends are cut and prepared with the use of a conventional clamshell cutting machine. This machine, fitted with form tools, is used to machine the grooves required to locate the connector’s retaining wires in the pipe periphery.

If access is available at the pipe ends and one of the pipes can be moved longitudinally, then the SRJ connector would be installed onto one of the pipes to half its ength and the mating pipe is then pulled into the connector.

If however, the pipes cannot be pulled longitudinally, i.e. a spooled installation between two fixed ends, the connector would be completely assembled onto one of the pipes. This would leave its outer end flush with the pipe end. Then the mating pipe would be lowered into position and when the pipe ends are butted, then then the connector is centralised.

For larger OD connectors, a hydraulically-activated unit is used to position the connector on the pipe, thereby eliminating seal friction.

Alternatively, normal manual pipe handling equipment can be used. In all cases, once in position, the SRJ connector is locked in place by fitting the retaining wires. Typically, the overall length of the SRJconnector is equal to twice the pipe’s OD, so the actual access requirements are kept to a minimum, making its use ideal in tight access situations, such as the hook up phase of a project.

 

Nominal Pipe Diameter Pipe OD SRJ Diameter
4”
101.6mm
4.5”
114.3 mm
8”
203.2 mm
8.625”
219.075 mm
12”
304.8 mm
12.75”
323.85 mm

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Benefits & Advantages

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Benefits

Safety
  • Cold work installation – eliminates the risk associated with Welding.
  • Reduces risk of fugitive emissions
Size / Weight
  • 40/50% more compact than a comparable flange. Closer pipe runs.
Speed of Installation
  • approx 3 hours per coupling with less skilled technicians.
Cost Reduction
  • Time savings 18/24 hours per connection compared to welded flange.

Advantages

The SRJ offers many benefits over other pipe connection methods: –
  • Withstands high internal pressures and has equivalent mechanical strength of a weld
  • Eliminates costly welding workscopes by replacing coded welders with trained operatives
  • Speed of installation compared to welding workscope
  • Enhances safety on-site and ATEX requirements by eliminating the risks of welding
  • Does not compromise internal pipe coating, unlike welding
  • Avoids the need to weld difficult materials such as CuNi, Monel and Duplex
  • Potential for testing post-installation with the SRJ equipped with integrity ports
  • Lightweight and compact, cutting transport costs and enabling closer pipe rack design
  • Can be dismantled and reassembled

Installation Times vs. Welding

PROCESS
10” 900Lb
SRJ
Pipe Cutting and Preparation
=
=
Pipe Alignment
=
=
Flange alignment and welding per flange
10.1
N/A
Pre Heat
2.7
N/A
Stress relieve
5.9
N/A
XRay
1.73
N/A
Coupling Installation
N/A
3
Connecting flanges / gaskets / bolts
3.7
N/A
Total Hours
24.13
3
SRJ Saving
21.13

Note – Pipe preparation times for SRJ and welding considered to be equal.

SRJ vs. ANSI Flanges

Nominal Pipe Diameter Pipe O/D
SRJ Diameter
ANSI 900 LB Dia
4"
6.4"
11.5"
8"
10.7"
15"
12"
15"
24"
Nominal Pipe Diameter Pipe O/D
SRJ Weight
ANSI 900 LB Dia
4"
35 lbs
125 lbs
8"
175 lbs
415 lbs
12"
480 lbs
767 lbs

Snap Ring Joint Limited, 9 The Esplanade, St.Helier, Jersey, JE2 3QA, UK.
tel: 44 (0) 1534 626 818
e-mail: info@srj-technologies.com
Snap Ring Joint Limited. All rights reserved