YZ Systems NJEX ZEO 6400, Инструкция и руководство по эксплуатации

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SECTION 1: THINGS TO KNOW - NJEX ZEO
YZ Systems Milton Roy • 201 Ivyland Road • Ivyland, PA • USA • 18974 • P: 281.362.6500 • www.yzsystems.com
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NJEX ZEO Version 04/13/2021
Theory of Operation
The NJEX ZEO brings a change to how we odorize gas. With the legacy NJEX systems, gas is
odorized by running a pneumatically driven pump at a varying stroke rate with a fixed pump
displacement. The NJEX ZEO odorizes gas by running an electrically driven pump at a constant
stroke rate and varying the pump displacement. The advantage of the ZEO system is you are
always odorizing with each stroke (at least 24 times per minute) and only the amount changes
to maintain the injection rate.
Operation of the NJEX ZEO centers around four primary components: the transfer pump,
verometer, injection pump with actuator, and the N-400 controller.
During normal operation, the injection pump injects odorant into the system at a rate determined
by the N-400 controller. The injection pump runs at a fixed stroke rate and the amount of odorant
injected is controlled by the actuator (ACC) which adjusts diaphragm displacement by controlling
the amount of hydraulic fluid pushed against the diaphragm.
The verometer serves as a temperature compensated meter, which verifies the amount of
odorant injected by the injection pump. The N-400 controller uses an input signal from the
verometer to determine the amount of odorant that has been injected, as well as the odorant level
within the verometer. Once the odorant level falls to 0%, the N-400 controller prompts the transfer
pump to fill the verometer. Once the verometer is filled, the N-400 controller stops the transfer
pump.
The N-400 controller allows the ZEO system to operate in either a proportional-to-time or a
proportional-to-flow mode. In the proportional-to-time mode of operation, the user inputs the
target lb/hr or kg/hr rate. The ACC adjusts the injection pump capacity to maintain this target.
In the proportional-to-flow mode of operation, the N-400 controller uses a customer provided gas
flow rate input signal and several operator input values to maintain the injection rate setpoint per
the measured flow signal. These operator input values include the odorant injection rate
(lb/MMCF or mg/m3) and the odorant density (lbs/gal or g/cc). The flow input signal is customer
provided by either a flow computer or other flow monitoring devices. In this mode, the controller
has the capability to distinguish between a low flow situation and a loss of flow input signal. For
systems with analog inputs, if a loss of flow signal occurs, and if programmed, the controller
automatically defaults back to a pre-selected percentage of the flow input.
If system redundancy is required, the NJEX ZEO system has two main options for the backup
system, NBS Output (Default) or Redundancy.
For NBS Output, the NBS output terminal can be connected to another YZ system such as the
N-300 Controller in a pneumatic NJEX unit or the Z-65 Controller in an LVO unit. In the instance
of power loss or injection pump diaphragm failure, the unit will be put into standby mode and will
signal the backup system to run.
For Redundancy, dual ZEO systems can be configured as Primary or Secondary on the N-400
controller and wired together to send a signal in the occurrence of a failure. The primary cabinet
will inject odorant and in the case of power loss, a low injection rate alarm, or pump failure, the
backup system will be started. During normal operation, the backup system will be held in
Standby mode. If the backup system fails due to an injection rate low alarm or pump failure, both
the primary and backup units will run until the systems are stopped and serviced.