4S-SERIES PRESSURE EXCHANGER ENERGY RECOVERY DEVICES
Energy Recovery, Inc.
16
ERI Document Number 80022-01-04
6.3.5 Measurement of PX Device Lubrication Flow Rate
In a PX energy recovery device, some of the high-pressure water flows through the
hydrodynamic bearing to low-pressure regions in the assembly. The lubrication flow rate varies
with system pressure according to performance curves available on Energy Recovery, Inc.’s
website. If the PX device is damaged by debris, overflow or insufficient discharge pressure,
excess lubrication flow may occur. Inversely, monitoring lubrication flow is a good way to check
the integrity of an operating PX unit. Lubrication flow can be determined using any of the
following three methods:
1.
Measure the flow rate of the low-pressure seawater to the main high-pressure pump and
the flow rate of the permeate. The difference is the lubrication flow rate.
2.
Measure the flow rate of the high-pressure brine to the PX unit and the high-pressure
seawater from the PX unit. The difference is the lubrication flow rate.
3.
Measure the flow rate of the low-pressure brine from the PX unit and the low-pressure
seawater to the PX unit. The difference is the lubrication flow rate.
Although each of these methods should provide the same result, Energy Recovery, Inc.
recommends measuring lubrication flow using the first method because the flow meters
necessary to collect flow data according to this method are typically already incorporated into the
SWRO plant design.
7.0 SPARE PARTS AND TOOL KITS
The PX Pressure Exchanger energy recovery device needs no scheduled periodic maintenance.
However, in the event that the PX unit is disassembled, Energy Recovery, Inc. recommends use
of the following:
ALL 4S-Series PXs: 4S Tool Kit – Energy Recovery, Inc. Part Number 20023-01
PX-45S, -70S, -90S: 4S Single Rotor Spares Kit – Energy Recovery, Inc. Part Number 20018-01
PX-140S:
4S Dual Rotor Spares Kit – Energy Recovery, Inc. Part Number 20019-01
Replacements for other components in the PX unit assembly are available. Refer to Section
13.0
for PX device component names and the bill of materials for the PX unit assembly.
8.0 MAINTENANCE
If the inlet and outlet flows are measured and balanced properly, the seawater is filtered and the
PX unit is properly flushed after every shut down (as described in Section
6.2
), the PX device
should operate maintenance- and trouble-free for many years. The PX unit needs no scheduled
periodic maintenance. There are no shafts, couplings, seals or lubrication systems to maintain or
monitor.
The PX unit is designed so that it can be assembled and disassembled in the field with basic tools
and equipment. The procedures provided in this subsection are for complete assembly or
A sample operating-log has been provided at the end of Section 8.0 and must be
submitted by fax or e-mail to Energy Recovery, Inc. in San Leandro, California
upon completion of the startup and balancing routines. Submittal of this form with
the initial startup data within 24 hours of startup is requested. The data must be
recorded daily and maintained during the life of the warranty to support any claims.
NOTE