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Magnesonics / Jerguson / Level Switches

Top Mount Displacer Operated Magnetic Level Switch

Name: Jerguson Top Mount Displacer Operated Magnetic Level Switch
Brand: Jerguson
Availability: InStock

JDC Series — Bulletin JS100.08 (August 2017) — A Product of Clark-Reliance

The Jerguson® Top Mount Displacer Operated Magnetic Level Switch uses a unique three-magnet latching mechanism to deliver failure-free performance in high-temperature, high-vibration, and demanding process environments. Endurance tested to over 850,000 cycles without failure — no springs, no cams, no mechanical wear points.

"The new switches are very rugged and dependable, and most importantly, they are mercury-free and safe for the environment… The Jerguson Tri-Magnet Level Switches have been in operation in our facility since May 2007."
— Maintenance Superintendent, Major Utility Power Generation Plant

Key Features

→Tri-Magnet Switching for Unparalleled Reliability

→Vibration Resistant — no springs or cams

→316 Stainless Steel Trim throughout

→Pump Control with wide differential

→Multi-Point Alarm capability

→ASME B31.1 & B31.3 Design

→Endurance tested to 850,000+ cycles

→Fully field adjustable — re-set displacers on cable

→Weatherproof (NEMA 4) and explosionproof (NEMA 4 & 7) enclosures

→FM, Class I, Division 1, Groups B, C & D approval (SA7F)

Principle of Operation — Displacer Mechanism

The displacer element is suspended on a stainless steel cable attached to a spring. The displacer is always heavier than its equivalent volume of the liquid in which it operates, and therefore will always extend the tension spring. Hanging freely in air, the spring extends to a predetermined length, limited by a mechanical stop to prevent overstressing. Attached to the spring is the magnet assembly which is free to move up or down as the spring extends or contracts.

As rising liquid submerges the displacer, a buoyant force is created equal to the weight of the displaced liquid volume. This buoyancy force reduces the apparent displacer weight, contracting the spring and moving the magnet upward inside the pressure tube to actuate the switch mechanism.

Two switch models are available: one for two alarm applications with narrow differentials, and one for pump control with appropriate wide differentials. The tri-magnet snap-action mechanism eliminates springs and all other mechanical elements prone to failure — endurance tested to over 850,000 cycles without failure.

Switch Mechanism Selection

Type	Application
X4, X8	General purpose — 10 amp mechanisms for general purpose duties up to 480°F
D4, D8	High temperature — 5 amp mechanisms for high temperature applications up to 750°F
H4, H8	Hermetically sealed — 5 amp mechanisms suitable for temperatures up to 480°F, contaminated atmosphere environments and intrinsically safe circuits. All moving parts and contacts enclosed in an inert gas-filled stainless steel enclosure.
P4, P8	Low current — 0.25 amp gold-plated contact switch mechanism for use in intrinsically safe or low-power circuits up to 750°F
E4, E8	Encapsulated — 5 amp switch mechanism sealed/encapsulated inside an aluminum housing, suitable for temperatures to 850°F

Switch Contact Configurations

Contact Type	Switch Models	Contact Arrangement	Switching Action
4 Contact	D4, X4, P4, H4, E4	2 × SPST	AA Make on Rise; BB Make on Fall
8 Contact	D8, X8, P8, H8, E8	4 × SPST	AA Make on Rise; BB Make on Fall

4-contact mechanisms can be linked for SPDT/SPCO operation. 8-contact mechanisms can be linked for DPDT/DPCO operation.

Dimensional & Operating Level Data

Dimensional drawings illustrate single-switch and dual-switch arrangements. Each switch point has a 0.56" (14 mm) deadband. The upper-to-lower switch separation in a dual-switch arrangement is 3.000" (76 mm).

Enclosure Type	Duty	Height G	Conduit Thread	Switch Adjustment	Rating
SA7, SI7	Explosionproof	13-1/4"	1" NPT	3-3/8"	NEMA 4 & 7
SA4	Weatherproof	12"	1" NPT	3-3/8"	NEMA 4

Materials of Construction

Designed in accordance with the requirements of ASME B31.1 & B31.3.

Component	Carbon Steel	Stainless Steel
Flanges / Fittings	ASTM A105	ASTM A182 F316
Displacer & Trim	316 SS	316 SS
Cable	316 SS	316 SS
Spring	316 SS	316 SS

→Option: Low Temperature Carbon Steel Chambers

→Option: Controls to Meet NACE Requirements

→Option: A Comprehensive NDT Package

Model Selection — Carbon Steel (JDC_D)

Final pressure rating is the lower of the displacer rating and the process connection rating. Minimum S.G. values are for approximation only with "Lowest Switch Trip Point" less than 12.00".

Model	SPDT Min. S.G.	DPDT Min. S.G.	Displacer Rating @ 100°F	Displacer Rating @ 750°F
JDC1D	0.72	0.80	350 PSIG	275 PSIG
JDC2D	0.60	0.60	300 PSIG	235 PSIG
JDC3D	0.65	0.69	740 PSIG	505 PSIG
JDC4D	0.65	0.69	1440 PSIG	935 PSIG
JDC5D	0.72	0.76	1000 PSIG	780 PSIG
JDC6D	0.36	0.38	300 PSIG	235 PSIG
JDC7D	0.47	0.49	750 PSIG	585 PSIG
JDC8D	0.58	0.60	1000 PSIG	780 PSIG
JDC9D	0.34	0.35	450 PSIG	350 PSIG

Model Selection — Stainless Steel (JDS_D)

Model	SPDT Min. S.G.	DPDT Min. S.G.	Displacer Rating @ 100°F	Displacer Rating @ 750°F
JDS1D	0.72	0.80	350 PSIG	275 PSIG
JDS2D	0.60	0.60	300 PSIG	235 PSIG
JDS3D	0.65	0.69	720 PSIG	425 PSIG
JDS4D	0.65	0.69	1440 PSIG	935 PSIG
JDS5D	0.72	0.76	1000 PSIG	780 PSIG
JDS6D	0.36	0.38	300 PSIG	235 PSIG
JDS7D	0.47	0.49	750 PSIG	585 PSIG
JDS8D	0.58	0.60	1000 PSIG	780 PSIG
JDS9D	0.34	0.35	450 PSIG	350 PSIG

Process Connections

Code	Connection Size	CS Rating @ 100°F	SST Rating @ 100°F	Notes
D2M	1" NPT	1000 PSIG	1000 PSIG	Requires internal access to attach displacer
D71	3" 150# R.F. ASME	285 PSIG	275 PSIG	Model JDC1D/JDS1D only, unless internal access is available
D73	3" 300# R.F. ASME	740 PSIG	720 PSIG	Model JDC1D/JDS1D only, unless internal access is available
D76	3" 600# R.F. ASME	1480 PSIG	1440 PSIG	Model JDC1D/JDS1D only, unless internal access is available
D91	4" 150# R.F. ASME	285 PSIG	275 PSIG	JDC1D/JDS1D on all nozzle schedules; 2D–4D to Sch. 80S
D93	4" 300# R.F. ASME	740 PSIG	720 PSIG	JDC1D/JDS1D on all nozzle schedules; 2D–4D to Sch. 80S
D96	4" 600# R.F. ASME	1480 PSIG	1440 PSIG	JDC1D/JDS1D on all nozzle schedules; 2D–4D to Sch. 80S
DB1	6" 150# R.F. ASME	285 PSIG	275 PSIG	JDC1D/JDS1D on all nozzle schedules; 6D–9D to Sch. 80S
DB3	6" 300# R.F. ASME	740 PSIG	720 PSIG	JDC1D/JDS1D on all nozzle schedules; 6D–9D to Sch. 80S
DB6	6" 600# R.F. ASME	1480 PSIG	1440 PSIG	JDC1D/JDS1D on all nozzle schedules; 6D–9D to Sch. 80S
D7M	3" MNPT	1000 PSIG	1000 PSIG	Model JDC1D/JDS1D only

Switch Mechanism Electrical Ratings

Switch Type	Wetside Temp. °F	AC VA	AC Max. Volts	AC Amps	DC Watts	DC Max. Volts	DC Res. Amps	DC Ind. Amps
X4	480	2000	440	10	50	250	10	0.5
D4	750	2000	440	5	50	250	5	0.5
H4	480	2000	440	5	50	250	5	0.5
E4	850	2000	440	5	50	250	5	0.5
P4	750	6	250	0.25	3.6	250	0.25	0.1
X8	480	2000	440	10	50	250	10	0.5
D8	750	2000	440	5	50	250	5	0.5
H8	480	2000	440	5	50	250	5	0.5
E8	850	2000	440	5	50	250	5	0.5
P8	750	6	250	0.25	3.6	250	0.25	0.1

4-contact types: two independent SPST contact sets — link for SPDT. 8-contact types: four independent SPST contact sets — link for DPDT.

Enclosure Types

Code	Duty	Cover Material	Base Material	Pressure Boundary	Max Switches
SA4N	Weatherproof	Aluminum Alloy	Aluminum Alloy	316 Stainless Steel	1–2
SA7F	Explosionproof — FM, Class I, Div. 1, Groups B, C & D	Drawn Steel	Aluminum Alloy	316 Stainless Steel	1–2

Ordering Information

Typical Model Number

JDC1D SA4N 1 X4 D71 L09.50

Position	Example Code	Description
Model	JDC1D	Carbon Steel Top Mount Displacer Switch
Enclosure	SA4N	Weatherproof Enclosure
Number of Switches	1	Single Switch
Switch Mechanism	X4	General Purpose, 4 Contact
Process Connection	D71	3" Class 150 Raised Face ASME
Lowest Switch Trip Point	L09.50	Rising Level, 9.50"

1.Completed Application Design Sheet required (JS200.08).

2.Minimum S.G. values are for approximation only, with "Lowest Switch Trip Point" less than 12.00". Actual minimum S.G. depends on the final design.

3.Final pressure rating of the unit is the lower rating between displacer and process connection.

4.Specify rising level switch point for a single switch, or upper switch of a multi-switch model. Falling level is 0.56" below rising level.

Typical Applications

→Separators

→Water Sumps

→Compressors

→Scrubbers

→Knock Out Pots

→Fractioning Columns

→Condensers

→Process Vessels

→De-actuators

→Condensate Tanks

→Storage Tanks

→Drainpots

→Service Tanks

→Accumulators

→Header Tanks

→Flush Vessels

→Effluent Sumps & Tanks

→Fuel Tanks

→Heat Exchangers

→Feedwater Heaters

→Lube Oil Tanks

→Surge Drums

ℹ

SureTest™ Rooftop Available

Top mount switches can be equipped with the SureTest™ Rooftop — a local manual test feature that allows the operator to simulate a high level and verify switch operation without breaking the pressure boundary. Learn more →

Warranty

All mechanical level devices are warranted free of defects in materials and workmanship for five years from the date of original factory shipment. If returned within the stated warranty period and upon factory inspection the cause of the claim is determined to be covered, the device will be repaired or replaced without cost to the purchaser, other than transportation.

Request Pricing — Jerguson Top Mount Displacer Switch

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