Emerson Daniel 762 User Manual page 18

Introduction
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A simple routine visual check can be done to determine if the oil in the sight glass is within
the recommended limits. This makes it easy for a pipeline operations team to be confident
of the surge relief valves readiness.
Note
The spring in the Daniel Nitrogen Loaded Surge Relief Valve is for shipping purposes to ensure piston
movement does not cause damage during shipment. This is the only purpose of this spring.
Note
Equal area on both sides of the piston allow the nitrogen pressure to be set at the actual set point
minus spring force rather than a calculated percentage.
Note
Oil in the reservoir of the Daniel Nitrogen Loaded Surge Relief Valve has many advantages. It allows
the piston seals to be exposed to a clean, lubricant fluid which helps to extend the service life of the
seals tremendously. In addition, it should eliminate the possibility of nitrogen gas permeating the
seals which will ultimately result in a leak and nitrogen consumption.
NOTICE
The Daniel Models do not comply with any internationally over-pressurization protection
recognized codes. What the Daniel Models do is to allow the movement of an undetermined
amount of substance within a pressurized system, not from a pressurized system.
8
Opening and closing speed is controlled by a unique check valve mounted to the
internal surface of the cylinder head. The opening of the valve is relatively
unrestricted, and response time is typically under 100 msec.
This results in an extremely fast opening response. The opening and closing speeds
are controlled by an orifice in the check valve.
Daniel Models 762, 763, 765, 766 and 767 Control Valves