TABLE OF CONTENT. 7-Operating mechanisms of Non-return valve with hydraulic damping cylinder

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2 TABLE OF CONTENT Title 1- Tilting-Disc Non-Return valves with counter weight (NVTW) 2-Parts list 3-Installation Non-return valve and Butterfly Valve 4-Dimensions 5-Installation of Non-return valves with counter weight 6-Non-return valves with hydraulic damping system (NVTD) 7-Operating mechanisms of Non-return valve with hydraulic damping cylinder 8-Selection of non-return valves with damping system 9-Positions of hydraulic cylinder on Non-return valve 10-Damping time adjustment 11-Operating Instructions 1. Safety Aspects 2. Description of Product and Range of Application 12-Performance and Mode of operation 13-Installation into the Pipeline Mounting 14-Maintenance 1. Replacing the shaft seal 2. Replacing the valve disc seal 3. Design with oleohydraulic damping device

3 1-Tilting-Disc Non-Return valves with counter weight (NVTW) Size: DN Pressure: PN bar Face to face: DIN EN series 14/ISO (DIN3202-F4) Flanges: DIN EN (DIN 2501) Application: These types of valves are used in water supply installations to stop the fluid flow in the opposite direction. The valve closing speed can be adjusted by changing the weight position along the lever. All of the seals of the valve bearing can easily be replaced. The standard seal material is NBR for up to 70 C (for gas up to100 C). For higher temperature and other fluids suitable seal material is available on request. Corrosion protection: Body and disc are fully coated with blue electrostatic epoxy powder coating (RAL 5005 or RAL 5015). Product descriptions: Reliable design Maintenance free The short face to face dimensions and low weight Body seat ring made of corrosion resistant steel Possibility for installation of weight and lever on both sides Eccentric disc operation Disc seat ring is corrosion resistant steel with seal for reliable sealing Disc and shaft are connected by key Seat ring : Stainless steel 304 rolled into the body Rugged body with disc suitable for fluid flow Working temperature: -25ºc up to +70ºc Test Pressure: DIN EN Sealing ring: Elastomer EPDM for water and NBR for gas Flange Dimension: DIN EN (DIN2501) Face to Face Dimension: DIN EN series 14 (DIN 3202 F4) Hydrostatic test Pressure (bar) according to DIN EN Nominal Pressure Test Pressure PN (bar) Body Seat Dimensions for working pressure 40 bars and higher as per request.

4 Non-Return Valve 2- Parts list Body Seating Surface Optional Design # 1 Normal Design Welded Directly onto the Body Optional Design # 2 Separate Seat Ring Pressed into the Body Welded Directly onto the Body No. Parts Name Material Body EN 1563/ EN-GJS Body Seating Surface 18Cr- 8Ni 3 Bearing Bush ASTM B148 UNS Disk EN 1563/ EN-GJS Disk Seat DIN EN / Shaft, Lever End DIN EN / Shaft, Free End DIN EN / Shaft Sealing DIN EN / O-ring NBR ( EPDM on Request) 10 O-ring NBR ( EPDM on Request) 11 Spacer Ring BRASS 12 Bearing Cover EN 1563/ EN-GJS O-ring NBR ( EPDM on Request) 14 Washer DIN ISO 898-2, Property Class 8, Zinc Plated 15 Hexagonal Bolt DIN ISO 898-1, Property Class 8.8, Zinc Plated 16 Cap EN 1563/ EN-GJS Internal Key DIN EN / Key Retainer DIN EN / Hexagonal Bolt ISO , Gr. A2, Property Class Counter Socket Screw ISO , Gr. A2, Property Class O-ring NBR ( EPDM on Request) 22 Lever ST Key High Strength Carbon Steel-St60 24 Spacer Ring BRASS 25 Cir clips Steel(FST) 26 Limit Stop EN 1563/ EN-GJS Socket Screw ISO , Gr. A2, Property Class Counter weight EN 1563/ EN-GJS Socket Screw DIN ISO 898-1, Property Class 8.8, Zinc Plated 30 Socket Screw DIN ISO 898-1, Property Class 8.8, Zinc Plated 31 Hexagonal Bolt DIN ISO 898-1, Property Class 8.8, Zinc Plated 32 Washer ISO 898-2, Property Class 8, Zinc Plated 33 Nut ISO 898-2, Property Class 8, Zinc Plated 34 rubber EPDM / NBR 1- Recoended Spare Parts 2- Parts Subjected to Wear * EN-GJS available on request.

5 3-Installation Non-return valve and Butterfly Valve Conditions for installation of flanged type Butterfly valve next to Non-return valve with counter weight and lever: Tilting disc Non-return valve With counter weight Spacer pipe Flanged type Butterfly valve For installation of non-return valve adjacent to a butterfly valve, the weight lever of the non-return valve must be on the left hand side in flow direction and the gearbox of the butterfly valve on the right hand side to prevent collision of the weight lever with the gearbox of the butterfly valve. DN L L a b c

6 PN 25 PN 16 PN 10 R 4-Dimensions DIN EN (DIN 2501) DIN EN series 14 (DIN F4) DN L ØD b ØK Ød2 n e1 e2 e3 e4 h1 h2 h3 a Approx.Wt. Kg Dimensions for working pressure 40 bars and higher as per request.

7 5-Installation of Non-return valves with counter weight Horizontal pipeline: Pos. 1 the right hand side of valve in flow direction. Pos. 2 the left hand side of the valve in flow direction. Pos. 3 both of the in flow direction. Vertical pipeline with flow direction upward: Pos. 4 the right hand side of valve in flow direction. Pos. 5 the left hand side of the valve in flow direction. Pos. 6 both of the in flow direction. Vertical pipeline with flow direction downward: Pos. 7 the right hand side of valve in flow direction. Pos. 8 the left hand side of the valve in flow direction. Pos. 9 both of the in flow direction. Note: Normally the lever and counter weight of all non-return valves with counter weight are assembled as shown in Pos.2. (Horizontal line) For other valve positions, the lever should be assembled according to the valve positions as shown in the above figures.

8 6-Non-return valves with hydraulic damping system (NVTD) Mirab co. non-return valves with counter weight can be equipped with hydraulic damping system for adjusting the opening and closing speed. With the damping system the opening and closing time can be adjusted, and the water haer effect can be prevented by adjusting the damping time. Application: To provide non-slam performance in places where water return through the valve is permitted. A flow control valve can adjust the opening and closing speed of non-return valve disc. Application examples: - Water supply line with pumps installed in parallel When the pump is turned off and the flow direction reversed, the valve closes, and if the valve does not have a damping mechanism, because the fluid deceleration may lead to check valve slam and consequent damage the system. In this case, the back pressure acting upon the closing valve disc would be equal to the pump pressure. - Water supply line with long and steep pipeline Pumping to a high elevation. Quick change in flow direction which results in extensive force. In this situation the amount of back pressure on the closed disk is caused by the amount of water column.

9 travel R 7-Operating mechanisms of Non-return valve with hydraulic damping cylinder Non-Return valve damped in open position Non-Return valve in 50% open position Non-Return valve damped in closed position Closing time can be adjusted up to max. 30-seconds as the standard, by a flow control valve.

10 pressure loss Δ P ( WC) pressure loss coefficient ζ opening degree φ R 8-Selection of non-return valves with damping system Order for non-return valve with damping device should contain back (or differential) pressure. If the standard types are equipped with hydraulic damping device on one side, due to shaft dimensioning and material, the maximum admissible back pressure is limited according to the table below: DN [] Maximum admissible back pressure ]bar[ If the Non-return valve is equipped with damping device on both sides, the maximum admissible back pressure will be doubled in the above table. Types for higher back pressure upon request. Illustration of tilting disc with counter weight of DN 400 and PN 10 installed in horizontal position. Due to geometrical similarity, this graph could also be used for other valve sizes. Fluid speed (m/s) --- Pressure loss when the valve is fully open

11 9-Positions of hydraulic cylinder on non-return valve Horizontal pipeline: Pos. 1 Weight and damping on the side of the valve in flow direction Pos. 2 Weight and damping on the right side of the valve in flow direction Pos. 3 Weight and damping both sides of the valve Vertical pipeline with flow direction upward: Pos. 4 Weight and damping on the side of the valve in flow direction Pos. 5 Weight and damping on the right side of the valve in flow direction Pos. 6 Weight and damping both side of the valve Vertical pipeline with flow direction downward: Pos. 7 Weight and damping on the side of the valve in flow direction Pos. 8 Weight and damping on the right side of the valve in flow direction Pos. 9 Weight and damping both sides of the valve

12 Damping Time [s] R 10-Damping time adjustment The valve opening and closing speed can be adjusted by damping time at the flow control valve Valve adjustment [Turns] Adjustment of damping time at the flow control valve [damped opening range 10 o, closing range 15 o ] If the Tilting-Disc Check Valve is equipped with mounted oleohydraulic damping device on both sides, the flow control valve of both oleohydraulic damping devices must be adjusted at the same time.

13 11-Operating instructions 1. Safety Aspects A number of prescriptions shows the way of achieving the goal of avoiding dangers caused by technical machinery and working devices, according to the stipulations concerning safety for technical equipment (DIN and following) as well as the respective regulations for prevention of accidents (UVV), it is necessary to restrict access to the moving range of the weight-loaded lever and the oleohydraulic damping device. Effective protective guards have to be installed by customers. On request we will supply suitable protective guards. 2. Description of Product and Range of Application Nominal Size [] DIN Nominal Pressure [bar] PN Hydrostatic test pressure [bar] for body seat Max. admissible Working Pressure [bar] at a working temperature of >70 C The Mirab co. Tilting-Disc Check valve is put on for water speeds under stable flow rates according to table: PFA [bar] Velocity of flow [m/s] 3 4 5

14 12-Performance and Mode of operation The Mirab co. Tilting-Disc Check Valves operate to the principle of a free-swinging check valve. The disc is double offset to a very high degree and is opened by the upstream flow. The closing moment resulting from the weight of the disc and weight-loaded lever acts against this opening moment. This closing moment initiates closing when the flow ceases. It can be reduced within certain limits by moving the counterweight on the lever towards the shaft. However, it must be in any case ensured that the valve disc closes even without counter pressure. The shaft of the Mirab co. Tilting-Disc Check Valves protrudes on both sides (key connection). As a standard, the weight-loaded lever is fastened on the left seen in flow direction, as shown in section, "Positions of hydraulic cylinder on Non-return valve", for installation into horizontal pipeline. For other installations, for example into vertical pipeline, the weight-loaded lever must be rearranged on the shaft. If necessary, the valves have to be fitted with weight-loaded lever on both sides. For more details see drawing in section, "Positions of hydraulic cylinder on Non-return valve". At the manufacturer s plant the valves are tested for strength and tightness according to DIN Installation into the Pipeline Mounting Before the installation, remove all packing material, check the pipeline for impurities and foreign matters and clean it if necessary. Install each check valve in the line with the narrow pointing in the direction of the flow! It is important that all around the valve there is enough space for easy installation and maintenance. For outdoor installation, the customer should protect the valve against the effects of the weather. During installation of the valve, the distance between the pipe flanges should exceed the valve face-to-face dimension of the valve by at least 20. This will ensure that the raised faces will not be damaged and the gaskets can be inserted. Steel-reinforced rubber seals are suitable for use as flange gaskets (consider resistance to flow medium and temperature). The mating flanges must be parallel and concentric. Bolt tightening must be even and diagonal to prevent distortion. Mirab co. Tilting-Disc Check Valves shall not be installed directly upstream or downstream of pipeline components, as bends, valves, etc., as due to the short face-to-face dimension of the valve, the valve disc extends beyond the body flanges. The valve disc could otherwise collide with these components or disturb the flow because the valve disc does not open or opens only partly (for DN 800 and larger also consider the stop when installing and removing the valve. A dismantling piece is required in this case. See table of dimensions, dimensions e2, e3, and e4). Recoended minimum distance to a pump connectors = 3 x DN.

15 Recoended minimum velocity = 1,5 m/s. Before filling the pipeline with water, check the valve for easy running: Operate the weight-loaded lever over the total travel (90 ). Do not drop the weight-loaded lever. 14-Maintenance Mirab co. Tilting-Disc Check Valves are equipped with maintenance-free plain bearings. The precise elastomer seal inserted into the metallic sealing face of the valve disc is replaceable. Precise elastomer seal and complete shaft seal are available as spare parts. Prior to carrying out works at the valve, the pipeline section has to be made pressureless and emptied. 1. Replacing the shaft seal For parts identification, see parts list. 1.1 Remove bolt, washer and weight-loaded lever from shaft (6). 1.2 Loosen hexagon bolts (15) and remove together with flanged bearing (12). 1.3 Dismantle complete spacer with O-rings (8,9,10) by means of two screw drivers. 1.4 Mount new spacer with O-rings as well as flanged bearing in reverse order. 2. Replacing the valve disc seal 2.1 Remove O-ring (21) 2.2 Rub grease approved for potable water on the new endless O-ring. Slightly extend O-ring and evenly press into dove-tail groove of the valve disc. 3. Design with oleohydraulic damping device Mirab co. Tilting-Disc Check Valves are equipped with oleohydraulic damping device, whenever a) To prevent water haer valve disc travels slowly 15% of its stroke before its fully closed position. Slow closing of the disc permits a little backflow. b) the valve shall open in a retarded manner under sudden acceleration of the flow medium (pump starts against the closed check valve) in order to prevent opening haer.

16 The oleohydraulic damping device acts in both limit positions and keeps the disc from chattering over the whole travel. The oleohydraulic damping device is supported on a bracket flanged to the valve body. The piston rod is hinged on the weight-loaded lever which is firmly connected to the valve disc by the shaft. When opening the valve, the disc can open up to approx. 10 before fully open position without any damping effect. On closing, the disc swings freely to approximately 15 before fully closed position without any damping being effected. Within this range, the inside diameter of the hydraulic damping device is increased so that oil can flow around the piston. From 10 to the open position and from 15 to the closed position, there will be a damping effect. The damping times can be manually adjusted by means of a flow control valve. The closing time is preset at the manufacturer s works considering the existing weight load, but not the backpressure acting on the valve disc and has to be readjusted to the requirements of the whole system when putting the valve into operation. Changes in the damping time are set at the rotary knob of the flow control valve. The high values of the ten-mark scale are used for quick closing, the lower values for slower closing of the valve. The times can only be set when a key is put into the lock of the rotary knob. The oleohydraulic damping device has to be checked for oil leakage at regular intervals. For refilling, open the filling screw at the cover of the damping device and fill hydraulic oil up to the lower edge of the filling hole. Then close filling screw tightly. Use only: Hydraulic oil, type H-LP 32 to DIN Kinematic viscosity at 40 C, 32 ²/s to DIN We recoend: The hydraulic oil should be replaced every 5 years. In case hydraulic damping devices are installed on both sides, please observe the following: For hoses and hose pipes, the maximum service life should be shorter than indicated in ZH 1/74 (HVBG). Even in case of appropriate storage and permissible strain, hoses and hose pipes are subject to a natural ageing process. Thus, storage and usability periods are limited. Therefore, hoses or hose pipes must be replaced at regular intervals, even if no defects concerning safety requirements can be detected. The period of usage should not exceed 6 years including a storage period of max. 2 years. Mirab co. can change the dimensions without any notice.