services thetestprocedure - corflex · services • capital project management and support •...

VALVESI------------------------------------------------ R3.51l1 high-pressure pinch valves order P inch valve manufacturer Corflex Engineering, which supplies pinch valves for low- to high-pressure applications, has receiveda R3.5- million order from a copper-mining project in Zambia for 500mm pinch valveswith a working pressure of 25 bar. The order was awarded on the condition that the valvesbetested and witnessed to be working at 1.1times the working pressure to ensure that they did not leak when closed. The force required to seal the valves is over 120t at a pressure of 27.5bar. .Corflex previously performed sealing tests on its valves; how- ever, this is the first time that a sealing test was required for a 500 mm pinch valve at this pressure. The most common method used to construct pinch valves uses rising actuators owing to its cost effectiveness. This is, how- ever,not suitable for pinch valves operating at high pressures as the pincher mechanism is held together using only two nuts. By using this construction method, the actuators have the tendency to move about, caus- ing the valve to jam. The poten- tial danger with this method is the high risk of bolts or nuts shearing. The valvesused in the test were fitted with four hydraulic cylin- ders - two on either side - and certified gauges were used. The sealing test is based on the recognised API 598 testing standard for valves. The Test Procedure The open valve is first filled with potable water and pressurised to a nominal 8bar to fullyexpelany residual air and to provide back pressure to the closing mechanism so that the sleeve can be pinched in an operating manner as normal as possible. Next, the hydraulic pressure is applied and the valve is fully closed. The upstream side is then pressurised to 27bar - 10%above nominal operating pressure - and the down-stream side is exhausted to zero pressure through the stand pipe. The observations throughout the test indicated that leakage was a droplet of water forming on, and falling from, the stand pipe. In this period, the upstream pressure did not reduce. The test was repeated with three valves and the same results were observed. MINING WEEKLY COUPON ON PAGE 64 E248583 PRESSURE TEST A representative from a Zambian copper mine had to bear witness to the Corflex pinch valve pressure test before a R3.5-million order was accepted RA TVM SERVICES • Capital Project management and support • Full service modification shop with engineering support • Technical and inventory support for projects. SUPPLIERS OF 1, 2 and 3 piece Stainless Steel Ball Valves KQife Gate Valves Butterfly Valves Gate Valves Globe Valves Check (Non return) Valves V-Strainers Y Check Valves Steam Traps Safety Relief Valves Control Valves BRANCHES Johannesburg Tel: 011 680 1~050 Fax: 011 680.2009 Durban Tel: 031 9142742 Fax; 031 9144729 cape Town Tel: 021 5562826 Fax: 021 5561989 [email protected] d DELTA 'P' P_F_l_O_'!'_K 2-0;-O/~-34-~-3~-3 U_CT_S_c_.c BEST PRICES (DIRECT TO VALVE MERCHANTS) BALL VALVES 15 < 50 1 PCE RB SS scrd 15<50 2 PCE FB SS scrd 15<80 3 PCE FB SS scrd 15 < 150 2 PCE FB SS flgd 25 < 100 2 PCE FB CS flgd BUTTERFLY VALVES wafer, unpinned. 40 < 600 Cl body SS disc EPDM liner dp DELTA 'P' FLOW PRODUCTS cc ..••••• _ T: 011 452 6826 F: 011 6094223 MINING WEEKLY I March 9-15 2012 63

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Page 1: SERVICES TheTestProcedure - Corflex · SERVICES • Capital Project management and support • Fullservice modification shop with engineering support • Technical and inventory support

VALVESI------------------------------------------------

R3.51l1 high-pressurepinch valves order

Pinch valve manufacturerCorflex Engineering,which supplies pinch

valves for low- to high-pressureapplications, has received a R3.5-million order from a copper-min-ing project in Zambia for 500mmpinch valveswith a working pres-sure of 25 bar.The order was awarded on the

condition that the valvesbe testedand witnessed to be working at1.1 times the working pressureto ensure that they did not leakwhen closed.The force required to seal the

valves is over 120t at a pressureof 27.5 bar..Corflex previously performed

sealing tests on its valves; how-ever, this is the first time that asealing test was required for a500 mm pinch valve at thispressure.The most common method

used to construct pinch valvesuses rising actuators owing to itscost effectiveness. This is, how-ever, not suitable for pinch valvesoperating at high pressures asthe pincher mechanism is heldtogether using only two nuts.By using this construction

method, the actuators have thetendency to move about, caus-ing the valve to jam. The poten-tial danger with this method

is the high risk of bolts or nutsshearing.The valvesused in the test were

fitted with four hydraulic cylin-ders - two on either side - andcertified gauges were used.The sealing test is based on

the recognised API 598 testingstandard for valves.

The Test ProcedureThe open valve is first filled withpotable water and pressurised toa nominal 8bar to fully expel anyresidual air and to provide backpressure to the closing mecha-nism so that the sleeve can bepinched in an operating manneras normal as possible.Next, the hydraulic pressure

is applied and the valve is fullyclosed. The upstream side is thenpressurised to 27bar - 10%abovenominal operating pressure -and the down-stream side isexhausted to zero pressurethrough the stand pipe.The observations throughout

the test indicated that leakagewas a droplet of water formingon, and falling from, the standpipe. In this period, the up-stream pressure did not reduce.The test was repeated with

three valves and the same resultswere observed.MINING WEEKLY COUPON ON PAGE 64 E248583

PRESSURE TESTA representative from a Zambian copper mine had to bear witness to theCorflex pinch valve pressure test before a R3.5-million order was accepted

TVMSERVICES

• Capital Project management and support• Full service modification shop with engineering support• Technical and inventory support for projects.

SUPPLIERS OF

1, 2 and 3 piece Stainless Steel

Ball Valves

KQife Gate Valves

Butterfly Valves

Gate Valves

Globe Valves

Check (Non return) Valves

V-Strainers

Y Check Valves