Description; Specifications - Fisher 4660 Instruction Manual

Type 4660
Available Configurations
High-low, low-only, or high-only set point capability
(1)
Input Signal
Type: Process pressure sensed with Bourdon tube
Bourdon Tube Ratings: See table 2 or 3
Overpressure Protection: Maximum allowable
emergency process pressures and maximum allow-
able process pressures to ensure set point readjust-
ability are shown in table 4
(1)
Output Signal
Zero or full supply pressure (automatically resets)
(1)
Supply Pressure
20 to 65 psig (1.4 to 4.4 bar)
Steady-State Air Consumption
Output Signal at Zero:
5 scfh ( 0.134 normal m
Output Signal at Full Supply Pressure:
0.05 scfh ( 0.00134 normal m
Set Point Adjustments
Continuously adjustable between 3 and 97% of
Bourdon tube rating; see table 2 or 3 for ranges
Performance in Percentage of Bourdon Tube
Rating
(1)
Repeatability 0.25%
Set Point P (see table 2 or 3)
min
Single High-Low Unit: 10% for up to 2500 psig
(172.4 bar) Bourdon tubes; 15% for 5000 and 7500
psig (344.8 and 517.1 bar) Bourdon tubes
Low-Only and High-Only Pair: 3%
Trip-to-Reset Zone (see table 2 or 3)
1.5%
Exhaust Capacity
C 15
g
Pilot Supply Flow Requirement
Pilot requires minimum of 150 scfh
3
(4.02 normal m /hr) to activate relay
1. This term is defined in ISA Standard S51.1-1979.
2. Scfh—standard cubic feet per hour (60 F and 14.7 psia). Normal m
3. Supply pressure at 35 psig (2.4 bar)

Description

The Type 4660 high-low pressure pilot (figure 1) acti-
vates emergency shutdown systems for flowlines, pro-
duction vessels, and compressors. The pilot can be
used with either a single or dual set point capability to
maintain full output pressure when the process is op-
erating within the set point range. The primary switch-
2
Table 1. Specifications
(2)(3)
3
/hr)
3
/hr)
(2)
3
/hr—normal cubic meters per hour (0 C and 1.01325 bar absolute).
(1)
Operating Conditions
Normal Operating
Condition
Nitrile Elastomers:
–40 to 140 F
(–40 to 60 C)
Fluoroelastomer Elastomers:
20 to 160 F
Ambient temperature
(–7 to 71 C)
Fluorosilicone Elastomers:
(Low Temperature Version)
–75 F to 160 F
(–59 to 71 C)
–20 to 200 F
Process temperature
(–29 to 93 C)
(1)
Operating Influences
Supply Pressure: 0.05% of Bourdon tube rating
for a 10% change in supply pressure
Ambient Temperature: 1.5% (standard construc-
tion) or 2% (low temperature construction) of Bour-
don tube rating throughout normal operating limits
with nominal reference
Time: 1% of Bourdon tube rating over 30 days at
ambient temperature nominal reference
Process Pressure: Range shift or set point drift
can occur if process pressure exceeds Bourdon
tube rating
Pressure Connections
1/4-inch NPT female
Mounting
Panel, rack, pipestand, or actuator
Approximate Weight
5 pounds (2.3 kg)
Options
Visual output indication,
relay, low-temperature version to –75 F (59 C)
316 stainless steel panel mounting flange
point indication, or
ing mechanism in this pilot is a block-and-bleed relay
assembly.

Specifications

Specifications for the Type 4660 high-low pressure
pilot are listed in table 1.
Nominal
Limits Reference
70 F (21 C)
70 F (21 C)
on Switch Point Sensitivity
flouroelastomers in
tamper-resistant front cover
set