AVK SERIES 55 AND 06 GATE VALVES, DN 450/500/600 1. Introduction The valve has a full and straight bore corresponding to the nominal diameter and can be installed independently of the flow direction. Although vertical installation is preferred, polyacetal shoes on the wedgeguides allow the valves to be installed in the horozontal or vertical position. Flow/pressure limitations outlined below should be observed. The valves are 100% factory tested hydrostatically to EN 1074-2, PN 10 and PN 16. The valves are suitable for installation under the following conditions: Flow velocity up to 5 m/sec. with max. 16 bar differential pressure across the closed valve. The valves comply with the general standard and market needs regarding installation, dimensions, materials, capacity and strength for large diameter valves, combined with the easy, cost saving operation of smaller valves. The valves have a standard gland flange to ISO 5210 (F16 flange and spindle diameter of Ø40 mm). Various optional extras like bypass, can be supplied factory fitted or supplied in kit form for retrofitting. See data sheet series 55 AND 06 and chapter 2.3 in this manual. The By-Pass system is not necessary for normal valve function, but can be used with advantage, if slow filling, or emptying of the pipe line is required and to ease operation by out balancing the pressure, whrn valve is closed against high pressure. To minimize water hammer the recommended opening speed is min. 3 min. from fully open to fully closed position. The AVK series 55 and 06 gate valves have many applications. IT IS THEREFORE IMPORTANT TO STATE OPERATING TEMPERATURE, PRESSURE, MEDIUM AND OPERATING CONDITIONS WITH ENQUIRIES/ORDERS, SO THE MOST SUITABLE VALVE WILL BE SUPPLIED FOR YOUR SPECIFIC PURPOSE. 1
2. Installation AVK series 55 and 06 gate valves are for below ground, chambered or burried installation. The valves must be protected against freezing by insulation, if installed in areas where freezing can be a problem. Ice in the valve or valve bonnet may lead to damage or malfunction. 2.1 Gasket To ensure tightness it is important to select the correct type of gasket for the medium. 2 gaskets with the correct flange size must be used. Torque/compression information must be obtained from the gasket supplier. 2.2. Bolts Table 1 Bolts DN Work pressure (bar) mm PN 10 PN 16 Quantity 450 M 24 M 27 20* 500 M 24 M 30 20* 600 M 27 M 33 20* * 2 pcs. 150 threaded rods are to be used in case bolt can not be mounted from maiden flange side around by-pass assembly series 55. 2.2.1. Installation and tightening The flanges should be cleaned before installation. The valve is placed between the pipe flanges and the bolts inserted. Tighten bolts loosely. Tighten bolts in a diagonal sequence (see below) to ensure flanges are pulled parallel. 2
Finally, tighten bolts to maximum torque levels given in table below, note that the gasket supplier must inform of the correct torque. Therefore the torques are only to be taken as a guideline: Table 2 Max. bolt torque Dimension Torque (Nm) M 24 200 M 27 250 M 30 300 M 33 450 2.3. Mounting of a By-Pass system IMPORTANT! Before mounting of a By-Pass system the main valve must not be under pressure, and the medium must be under the level of the By-Pass inlet on the side of the valve. Preparation of the main valve The 2 blind flanges / blind caps on the By-Pass bosses are removed and the inlet area of the valve are thoroughly cleaned for dirt and impurities. 3
Preparation of a By-Pass system for series 55. The 16 studbolts are screwed into the two cast iron bends, 8 pcs. in each, and the bends are fitted to the By-Pass valve, together with the mating gaskets (see drawing). The nuts are loosely fastened to ensure that the bends can move freely in relation to the valve. Mounting Series 55 by-pass (picture below): The By-Pass system is mounted on the main valve together with the cleaned gaskets (new gaskets are reccomended), and the previously removed nuts and washers are re-used for fastening. All nuts are in principle tightened as shown on the drawing under chapter 2.2.1. The nuts are to be tightened with approx 100 Nm. The By-Pass system is now ready for use. Mounting Series 06 by-pass: The by-pass is mounted in the holes on the side of the valve. Check by-pass bend for lubrication on o-rings before mounting. Mount the by-pass valve between the bend loosely. Mount the bracket plate to secure the bend in the valve. Torque the bracket plate bolts to approx. 80 Nm. Torque the bolts/nuts on the valve flanges with approx. 100 Nm. The bypass is now ready for use. 3. Operation The valve can only be used as an ON/OFF valve. Therefore the valve must be FULLY opened or fully closed during operation. 3.1. Right hand closing valves, CTC valves. 4
3.1.1. Closing From factory the valve is delivered with the wedge in almost closed position. By manual operation the valve is closed by turning the handwheel clockwise until the valve is completely closed. For closing torque by manual operation see table 3. Valves with actuators are closed by adjusting the actuator, so that the output shaft moves clockwise in the actuator closing direction. The on/off torque switch should be adjusted, so that the valve is not closed/opened with a higher torque than indicated in table 3. Going to closed position the actuator shall be switched off by means of the on/off torque switch, not the limit switch. The limit switch can be used as alarm indication in close direction by setting it 10 mm above fully closed. See later description of typical operation with electric actuator. 3.1.2. Opening By manual operation the valve is opened by turning the handwheel anti-clockwise until the wedge is fully open. Valves with actuators are opened by adjusting the actuator, so that the output shaft moves anti-clockwise in the actuator opening direction. The on/off torque switch shall be adjusted, applying an opening torque of 500 to 700 Nm. Going to open position the actuator shall be switched off by means of the on/off limit switch. The limit switch shall in open position be set to 1 (one) revolution before fully open. 3.2. Left-hand closing valves, CTO valves. IMPORTANT! From factory the valve is delivered with the wedge in almost closed position. By manual operation the valve is closed by turning the handwheel anti-clockwise until the valve is completely closed, for closing torque by manual operation see table 3. 5
Valves with actuators are closed by adjusting the actuator, so that the output shaft moves anti-clockwise in the actuator closing direction. The on/off torque switch should be adjusted, so that the valve is not closed/opened with a higher torque than indicated in table 3. Going to closed position the actuator shall be switched off by means of the on/off torque switch, not the limit switch. The limit switch can be used as alarm indication in close direction by setting it 10 mm above fully closed. See later description of typical operation with electric actuator. Table 3 Max. closing Turns Free running Rupture DN torque (Nm) to open torque (Nm) torque (Nm) (pressureless) 450 450*/500** 40 25 2500 500 450*/500** 44 25 2500 600 500*/700** 53 25 3200 * Series 06 ** Series 55 For electric actuators the recommended opening speed is min. 3 min. corresponding to max. 19 turns/min. 3.2.2. Opening By manual operation the valve is opened by turning the handwheel clockwise until the wedge is fully open. Valves with actuators are opened by adjusting the actuator, so that the output shaft moves clockwise in the actuator opening direction. The on/off torque switch shall be adjusted, applying an opening torque of 500 to 700 Nm in the fully open position. Going to open position the actuator shall be switched off by means of the limit switch. The limit switch shall in open position be set to 1 (one) revolution before fully open. 6
Please note the phase follow is important since wrong phase will cause stall torque to open, thus causing permanent damage to the valve!!! Wiring diagram recommended by AVK is to be found on the last page in this installation manual. If any doubt please contact nearest AVK sales outlet. 3.4. Marking The valves are marked with a label, stating general information such as testing, application etc. 4. Maintenance 4.1. General If the valve is installed according to AVK's instructions, it is maintenance-free. However every 4-5 months it is recommended if possible: 1) To make a routine check of the valve for leaks around the stem and the flange gaskets. All seals will in the course of time be influenced by air and sunlight, and careful checks can reveal such leaks. 2) To adjust the bolts in the flange connections as the compression of the flange gaskets may relax in the course of time and thus leaks may arise. Please observe the bolt torques and sequence table under chapter 2.2. 4.2. Replacement of stem sealing AVK valves are factory lubricated and maintenance-free. If it should be necessary to exchange the stem seal the following procedure must be observed. 7
4.2.1. Before replacement Before replacement, the valve size should be advised to supplier. A gasket set will be delivered consisting of: - 1 wiper ring - 2 internal stem seal O-rings - 1 gland flange O-ring - 1 nylon bearing 4.2.2. Disassembling Important! Before replacement of the stem sealing the valve must be fully opened and not be under pressure. This is done by turning the handwheel in opening direction until impact. It is very important to ensure that the wedge is fully open. 1) The 4 gland flange bolts (pos. 3) are unscrewed and the gland flange (pos. 6) is lifted out and pulled off the stem. 2) Wiper ring (pos. 1), O-rings (pos. 2, 5) and bearing (pos. 4) are carefully removed without damaging the gland flange. 8
4.2.3. Assembling 1) The internal surfaces of the gland flange are cleaned and checked for damages. 2) The new O-rings, wiper ring and plastic bearing are lubricated all over with a thin layer of silicone grease (e.g. ROCOL : Mx 22) 3) Wiper ring, plastic bearing and O-rings are carefully fitted in the cleaned gland flange (see figure) 4) Stem are cleaned and checked for damages. 5) The stem is applied a thin layer of silicone grease (e.g. ROCOL : Mx 22) 6) The gland flange is fitted on the valve and fixed with the 4 gland flange bolts (pos. 3). Please ensure that the O-ring (pos. 5) is correctly mounted in the recess. The bolts are tightened with a torque of 100 Nm. 7) The valve can be closed again by turning the handwheel in closing direction. 9
AVK product number 5540049 AVK International A/S/2008-06-30 515535GB