Dual Pilots; Field Test Connection; Single, Dual And High Capacity Filters (Optional) - GE Baker Hughes 2900-40 Series Maintenance Manual

XXII. 2900-40 Series POSRV Options (Cont.)
B. Dual Pilots
A dual pilot arrangement (Figure 46) is available for
applications in which the pilot valve soft goods require
monitoring and/or maintenance more often than the main
valve. In this installation, the pilot valves may be alternated for
maintenance, without bringing the system down.
Figure 44: Dual Pilots
ATTENTION!!
When servicing dual pilots, procedures need to be in place
to perform a tag out / lock out of pilots under pressure if
they are in service.
C. Field Test Connection
A field test connection is standard on all pilot valve types. This
allows the stroking of the valve with an auxiliary media, e.g. air
or nitrogen. An internal check valve is present in the field test
connection isolating the inlet media from the test media and
at the same time, allowing the valve to open normally in the
event of a system over pressurization during a field test. The
test port connection is a .375" (9.53 mm) tube fitting equipped
with a bug screen.
For all applications on air, water over 140°F (60 °C), or
steam service, ASME Section VIII - Division 1 requires each
pressure relief valve to have a lifting device such as a field test
connection or a means of connecting or applying pressure
to the pilot to verify that the moving parts essential to good
56 | BHGE
operation are free to move. (Reference UG 136(a)(3)). The
lifting lever or field test connection may be omitted under
Code Case 2203. All orders for pressure relief valves without
levers or field test connection for steam, air and water over
140°F (60°C) must state specifically that the valves are being
purchased per Code Case 2203. The purchaser is responsible
for obtaining jurisdictional authorization for use of Code Case
2203.
D. Single, Dual and High Capacity
Filters (Optional)
Figure 45: Sensing Line Filter
Filter options are available for dirty applications. These filters
are installed in the pilot inlet sensing line. For the 39PV, an
optional sensing line filter is available (Figure 45). This filter
has a 316 stainless steel body, Teflon
micron stainless steel filter element. Other high capacity filter
options (Figure 46) include:
1. A carbon steel cadmium coated filter body with a 35
micron stainless steel element; and
2. An entirely stainless steel filter arrangement. These
filters may be equipped with a manually operated needle
valve which allows for purging the filtered material while
the valve is in operation. All filter elements are stainless
steel, and all filters, including carbon steel, conform
to NACE Standard MR0103 and MR0175. A dual filter
arrangement (Figure 47) is available for applications in
which the customer is unsure of the filter maintenance
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