HGC

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NORMEX Hydrodynamic Guided Closing (HGC)

Fine application difference of check valves compelled Normex to come up with a new check Valve design named as Hydrodynamic Guided Closing (HGC). The closing mechanism in guided and backed with return spring for quick closing. This valve has inherent ability to arrest water hammer. Normex has succeeded in keeping very low pressure losses in this valve also.

n Low pressure drop (Hydrodynamic)

n Perfect sealing (Guided closing)

n Eliminates water hammer

n Can work vertically, horizontally or angular

n Compact Size, Silent Operation

HGC Non-Return Valves

Principle :

When the pump starts, the disc moves upward and the specially designed profile of the disk and body gives passage to the liquid / air without causing change in its velocity. This gives the aero / hydro dynamic effect, which results in minimum pressure drop (See fig.). When the pump stops, the disc moves backward quickly (Mouse over fig.). Because of long axial guide there is no displacement of the disc while closing. This & the concentric machining results in perfect sealing. In addition, as the valve is closed before the back flow starts, the problem of water hammering is eliminated.

Dimensions

Size(A) (mm)	D	W	H
40	150	85	85
50	165	105	100
65	185	128	120
80	200	156	140
100	220	194	170
150	285	264	230
200	340	346	290
250	406	430	355
300	457	500	398
350	527	600	475
400	578	686	560

Part List / Materials of Construction

Part	Description	Standard	Special
1	Body	Cast Iron	Cast Steel / St. Steel
2	Closing disc	S. G. Iron	Cast Steel / St. Steel
3	Guide	Cast Iron	Cast Steel / St. Steel
4	Sealing ring	Nitrile Rubber	Neoprene, Viton, Teflon etc.
5	Seat ring	L. T. Bronze	St. Steel / Teflon (PTFE)
6	Guide brush	L. T. Bronze	St. Steel / Teflon (PTFE)

Pressure rating

Size 150 - 300 mm = PN 16

350 mm = PN 16

Body test : 1.5 times rated Pressure

Seat test : 1.1 times rated Pressure

Technical Comparison

Check valve - Hydrodynamic Guided Closing (HGC) & Conventionally used Flap type
Normex HGC model H-01	Conventional Flap type
Innovative design, focused to eliminate all constraints of conventional one and offer optimum performance	Conventional design carries lot of constraints.
Internals designed in such a way that laminar flow is not disturbed to a large extent.	Turbulance is generated in fluid flow due to design limitations.
Very low pressure drop acros the valve which saves energy, reduces pump cycle time duration	Comparatively high pressure losses, requires more energy increases pump cycle time duration.
Valve closing mechanism is guided by precise guide & plunger mechanism which ensures perfect sealing.	Hing-pin-disc closing mechanism has lot of play which results in leakages.
Closing mechanism supported by spring force eliminates hammer to a large extent.	Closing mechanism is by back force of fluid hence maximum effect of hammer which causes many a times damage of pump or bursting of pipes.
Compact space saving design. Reduces face-to-face length. Light weight hence easy handling.	Standard full length valve higher in weight.
Vertical or horizontal installation is easily possible.	Installation recommended for horizontal position.
Symmetrically shaped design hence no top or bottom side selection for installation.	Cover side should be always on top for installation.
Material used is of grade FG 260 having higher tensile strength (26 N/mm2)	Material recommended is FG 200 having lower tensile strength (20 N/mm2)

For more details contact Normex.

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