WellMark 2001NB Installation, Operation & Maintenance Instructions

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Page 1

Series

2001NB

Installation, Operation & Maintenance Instructions

for Series 2001NB Pneumatic Level Control

Note: This document is to be used in conjunction with WellMark Catalog Document, Section No.

3.1, “Series 2001NB Pneumatic Level Control”, pages 1 through 3.

WARNING!

Over-pressure of this control or installation of the control in applications which may see pressure levels beyond those for which the control is designed may result in leakage and/or catastrophic failure. This failure could result in leaking gas, or produced liquid, damage to surrounding equipment and/or environment, personal injuryor death.

Suitable pressure-relieving devices, as recommended by appropriate codes or standards, should be installed in your system to assure that maximum rated pressures arenot exceeded.

Specifications

Connections

Process 2” MNPT Std. (Others avaialble) Pilot 1/4” FNPT Case Exhaust 1/8” FNPT

Application

The Series 2001NB Pneumatic Level Control is designed for use in liquid level and interface liquid control applications. The unit is available in either Snap-Acting or Throttling configurationand is field reversible for either Left-hand or Right-hand orientation. Furthermore, the unit can be set up for Direct or Reversing Acting operation. This standard displacer is 1-7/8” x 12” PVC in horizontal configuration. Displacers of other materials and dimensions, as well as VerticalDisplacersareoptionallyavailable.

VesselInstallation

WARNING!

Prior to installation of the 2001NB Level Control system must be isolated from pressure. Failure to do so may result in personal injury, environmental spill concerns and/or damageto equipment.

Insure that threadedconnections on both the 2001NBand the vessel are clean, free of debrisandundamagedpriorto installing. Install the Displacer (32) onto the Displacer Arm (30) by threading it together (Note: the Displacer Bushing (31) should already be installed in the Displacer). If the unit is configured for Vertical Displacer Assemby, theAdapter (44) will already beattachedto the DisplacerArm. In this case, install the Displacer by threading it onto theAdapter. Snug all threaded connections firmly.

Output

Throttle (Proportional) 3-15 psig or 6-30 psig Snap-Acting 0 to Full Supply

General

Repeatability 1.0% of Full Scale Dead Band 5.0% of Input Scale Linearity 2.0% of Full Scale Ambient Temp. Effect 1.0% @ -40°F

3.0% @ +180°F Specific Gravity 0.4 Minimum Temp. Limits -40°F to +200°F

(Displacer is limiting factor) Pressure Rating 6000 psi Pilot Operating Pressure Normal: 20-35 psi

Overpressure Protection: Gauges are the limiting factor.

Maximum Pressure without Gauges 125 psig

The Company, L.L.C. Oklahoma City, Oklahoma Tel: (405) 672-6660 Fax: (405) 672-6661

Install the Control in the vessel. Connect instrument supply line to SUPPLYport on back. Connect control valve signalline toOUTPUT port on back. Use asuitable threadsealant to assure leak-tight make up and to avoid thread galling. Do not overtighten.

CAUTION! Maximum allowable pressures for this level control are determined by the rating of the connection. Threaded connections are rated to 6000 psi @ 100°F. Flanged connections are subject to the maximum ratings as specified by ASME B16.5 for specific pressure classes and temperatures. These pressures should not be exceeded and proper overpressure protection should be employed on vessels where pressures above maximum may occur. Likewise, displacer material and configuration should be considered when determining suitability for a particular application.

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Series

2001NB

Operation

The 2001NB Level Control utilizes a balanced method, whereby a spring acting on a lever balances the weight of the displacer in the vessel. As liquid rises in the vessel, force is made available via the Torque Bar (16) and Fulcrum (26), to the pilot proportional to the weight of the displaced liquid. As the liquid level rises the amount of force increases to the pilot.

Direct-Acting

configuration, whereby rising level Pilot output. When the unit is configured for Direct-Acting operation the Fulcrum willbe located either left or right of the pivot dependingupon whether the unit is Left Hand Mount or Right Hand Mount as illustrated below.

LEFT HAND MOUNT RIGHT HAND MOUNT

FULCRUM

psi psipsi psi

PIVOT PIVOT

increases

FULCRUM

Proportional Band, when referring to a throttling control, is the ratio of displacer actually used as compared to the overall length of the displacer. Forinstance, a50% proportional band would utilize6” of a 12”displacer to achieve a 3-to-15 psi output.

FULCRUM

PILOT

FLAPPER

BAR

The Dump Span and Proportional Band are adjusted by moving the Fulcrum along the Flapper Bar as necessary to achieve the desired result.

Level Adjustment

- The Displacer’s weight is held in balance by the Spring (21). Since the Displacer is buoyant, as the level rises the apparent weight or of the Displacer decreases. As a result of

TORQUE BAR

PILOT

mass

FLAPPER BAR

FULCRUM

psipsi

Displacer’s apparent weight decreases as fluid level rises

DIRECT-ACTING

Rising level INCREASES Pilot output

Reverse-Acting

configuration (rising level Pilot output)

decreases

can be accomplished by moving the Fulcrum to the opposite side as shown below.

LEFT HAND MOUNT RIGHT HAND MOUNT

FULCRUM

PIVOT

psi psi psipsi

REVERSE-ACTING

Rising level DECREASES Pilot output

Span or Dump Span

refers to the differential between ON and OFF. This is determined by the position of the Fulcrum along the Torque Bar.

FULCRUM

PIVOT

SPRING

ADJUSTMENT ARM

Rotates down, relieving pressure on Torque Bar

Differential force increases as Displacer is unweighted

the rising Displacer the Adjusting Bar rotates, relieving pressure on the Torque Bar. This results in an increase in differential Spring force, transmitting that force to the Pilot poppet via the Fulcrum and Flapper Bar. Increasing tension on the Spring lowers the sensed level. Conversely, decreasing the spring force raises the sensed level.

Interface Operation

Some systems require control at theinterface distinction between the hydrocarbon and water. This is referred to as . It

interface operation

is possible to adjust the Spring to a point at which the hydrocarbon liquid completely envelopes the displacer without transmitting enough force to engage the pilot and produce any output.

Water has a higher specific gravity than hydrocarbon and naturally separates lower, with hydrocarbon liquid rising above it. When properly adjusted, watercan riseto alevel on the displacer,changing its apparent weight and causing enough force to engage the pilot, which will then result in output. The 2001NB unit’s broad range of control allows liquid interface sensing.

The Company, L.L.C. Oklahoma City, Oklahoma Tel: (405) 672-6660 Fax: (405) 672-6661

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Pilot Operation

Snap-Acting Pilot • No-Bleed On/Off Flow Action

The Snap-Acting Pilot is comprised of two inner valves. Valve (1) admits system supply gas to output. Valve (2) controls system exhaust from output. Valve (1), as shown in the closed position (Fig.

1), is held closed by force exerted from supply gas. When upward Flapper Bar forces transferred to Valve (2) is sufficient enough to overcome supply force, the ball snaps upward, allowing supply pressure to communicate to output port, which operates the diaphragm motor valve (not shown). The spherical end of Valve (2) closes the exhaust port the instant the ball snaps upward and remains seated against supply pressure until force on the valve diminishes. As force is removed from Valve (2),causing it tounseat, a simultaneous action occurs, causing Valve (1) to seat instantly, closing the supply port to ouput and opening output to exhaust, thereby allowing the diaphragm motor valve to reverse it’s action.

Throttle Pilot • No-Bleed Modulating Flow Action

The Throttle Pilot utilizes a diaphragm, which creates a forced balance Pilot (Fig. 2). Output pressure acts upon the diaphragm causing it to push back at the same force being applied to the lower seat. More force on the seat produces a proportionate increase in Pilot pressure. When the Flapper Bar of the control exerts upward force on the lower valve seat, it forces the lower seat closed against valve body and opens the supply valve. Supply pressure enters the system, increasing until the control and diaphragm motor valve (not shown) pressure equalsthe FlapperBar force and produces a forced system balance. The control willstay in this position until adecrease in thetank level reduces the force allowing exhaust, or an increasein the level produces an action as described. System supply gas does not flow while the Pilot is in balance.

Series

2001NB

IMPORTANT! Although the 2001NB Level Control is appropriately referred to

“No-Bleed”

as , all pneumatic systems require that the diaphragm operated motor valve exhausts or pressureoff the diaphragm once the valve has completed its actuation cycle. This vented gas, along with the gas within the lines leading from the control to the valve will vent back through the control. This clear distinction, between gas and gas must be made and understood. As with any or control, the intent is to stop the unnecessary bleed of gas between valve actuation cycles. The 2001NB Level Control will accomplish this task. It will not however, nor will any other or device stop the required venting of gas from the diaphragm and lines once the valve has cycled.

The Company, L.L.C. Oklahoma City, Oklahoma Tel: (405) 672-6660 Fax: (405) 672-6661

CAUTION!

“bleed” “vent”

no- low-bleed

vents

no- low-bleed

The 2001NB Level Control has a sealed box which allows the user to pipe vent gas away from the facility as needed. This is highly recommended if the control is to be mounted inside an enclosure that might result in a dangerous build up of gas. Failure to do so may result in damage to equipment, personal injury or death.

SUPPLY

OUTPUT

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Series

2001NB

Startup

Assure free-travel of the Displacer and DisplacerArm by rocking the Torque Bar by hand and observing corresponding movement of Displacer. The Displacer Arm should be centered in the vessel nozzle to assure that the vessel nozzle does not inhibit free operation. Displacer Arm should be parallel to the ground at installation.

LEVELADJUSTMENT

The controller is factory-set for average level and sensitivity.

To DECREASE LEVEL

turning theAdjustment Wheel to the

ADJUSTMENT WHEEL

To INCREASE LEVEL -

theAdjusting Wheel to the

ADJUSTMENT WHEEL

- Increase the compression of the Spring by

RIGHT.

SPRING

psipsi

DECREASE LEVEL

by increasing Spring compression

RIGHT

Decrease Spring compression by turning

LEFT.

SPRING

psipsi

INCREASE LEVEL

by decreasing Spring compression

SETTING INTERFACE LEVEL

The controller is factory-set for average level and sensitivity. Generally speaking, interface operation is most successful when there is a substantial differential in specific gravity between the two liquids. Interface cannot be reliably achieved with a displacer-type control with specific gravity differentials less than 0.1. Also, the sensitivity of the interface control is increased by the size of the displacer. Therefore, it is usually advantageous to use the largest displacer available, which will fit into the vessel.

NOTE: The presence of foam in the interface zone may affect the accuracy of the control.

FULCRUM

PIVOT

1” 2

1. Set Fulcrum approx. 1/2” from

pivot pin.

ADJUSTMENT WHEEL

SPRING

psipsi

Reduce Spring tension slowly by

FLAPPER

BAR

PILOT

turning the Adjusting Wheel to the

Allow the upperfluid to rise until

LEFT.

it completely submerges the Displacer.

Next, fine-tune the adjustment by turning the Adjusting Wheel to

RIGHT

the until an output signal is attained.

Finally,turn theAdjusting Wheel back to the until the output signal returns to

ZERO.

LEFT

2. Allow the lower liquid to rise until the desired interface level is

LEFT

ADJUSTING PROPORTIONAL BAND (SPAN)

Loosen Thumbscrew on Fulcrum and position the Fulcrum along the Flapper Bar.

ToDECREASE BAND (Increase Sensitivity)

Slide Fulcrum along Flapper Bar toward

SNAP

RING

FLAPPER

FULCRUM

PILOT

BAR

Snap Ring.

attained. Fine tune by slowly turning theAdjusting Wheel to the

RIGHT

until an output signal is obtained. Finally, slowly turn the

Adjusting Wheel to the until the output signal returns to

LEFT

ZERO.

3. To obtain a shorter dump span, slide the Fulcrum away from the pivot and repeat the above procedure.

Maintenance

WARNING!

Prior to maintenance of the 2001NB Level Control system must be isolated from pressure. Failure to do so may result in personal injury, environmental spill concerns and/or damageto equipment.

The 2001NB Level Control is designed to provide years of reliable service. However, build up of debris, paraffin, etc inside the

ToINCREASE BAND (decrease Sensitivity)

Slide Fulcrum along Flapper Bar away from Snap Ring.

SNAP

RING

FLAPPER

BAR

FULCRUM

PILOT

controller Body can interfere with proper functioning. A regular

Once desired band/span is achieved re-tighten Thumbscrew.

maintenance program should include checking for this condition.

The Company, L.L.C. Oklahoma City, Oklahoma Tel: (405) 672-6660 Fax: (405) 672-6661

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Series

2001NB

Maintenance- continued

General Disassembly

Note: This procedure does not include removal or servicing of the Pilot. Refer to section elsewhere on this page for information specific to removal of Pilot. Also, for reference see Sectional Diagram and Parts List on Page 6.

Relax compression on Spring (21) and remove along with the Upper Guide (22). Remove the Stud (19) andAdjustment Wheel(20).

Remove NylocNut (28) from Stud (23) and slide the Flapper Bar (24) off Stud. DO NOT REMOVE THE STUD, as it is press-fit into the Control Box. Fulcrum (26) and Thumbscrew (27) should remain in place on the Flapper Bar.

Remove a second Nyloc Nut (28) from the Pivot Shaft (6) and slide Torque Bar off the PivotShaft (6).

Hold the Adjusting Bar (14) while loosening two Capscrews (15). Once Adjusting Bar is loose, remove it along with the Adjusting Screw (17) from the Pivot Shaft. The Adjusting Screw need not be removed from theAdjusting Bar. Shaft.

Remove two Capscrews (12) holding the Control Box (1) to theBody (5) and disassemble Control Box from Body.

Slide the Spacer(11) from the Pivot

Temporarily install the Torque Bar onto the Pivot Shaft. Position the Level Adjusting Bar andAdjusting Screw such that the Torque Bar is parallel with the Displacer Arm (30) when the tip of the Adjusting Screw is touching the bottom of the TorqueBar.

Remove the Torque Bar, being careful not to disturb the position of the Adjusting Bar, and fully tighten the two Capscrews securing the Adjusting Bar to the Pivot Shaft. DO NOT OVERTIGHTEN.

Slide the Torque Bar back in place with the hole for the Upper Guide oriented on bottom and in proper position to accept the Upper Guide once the Spring is re-installed. Secure the Torque Bar with the Nyloc Nut, leaving approx. 1/16” clearance between the bottom of the nut and the Torque Bar.

to move freely on the Pivot Arm. Tightening the Nyloc Nut too much will inhibit this free travel.

Slide the Flapper Bar back onto the Stud and secure with the other Nyloc Nut. IMPORTANT! Do not over-tighten this nut, as the Flapper Bar must be able to move freely on the Stud.

Re-install the Stud and Adjusting Wheel. Install the Spring and Upper Guide, engaging the extrusion on the Upper Guide into its mating hole on the bottom of the TorqueBar.

Pilot Removal/Replacement

IMPORTANT! The Torque Bar must be able

General Reassembly

Mount the Control Box to the Bodyusing the two Capscrews. Screws should be tightened to 6 ft-lbs.

Install the Spacer on the Pivot Shaft.

If the Adjusting Screw was removed from the Adjusting Bar during disassembly it should be refitted, threading it into the Adjusting Bar until an equal amount of threads is showing above and below the Adjusting Bar.

Slide the Adjusting Bar onto thePivot Shaft, against the Spacer, such that theportion through which theAdjustment Screw isinstalled is on the opposite side from the Body (see below).

psipsi

ADJUSTMENT

on opposite side from BODY

Snug, but the two Capscrews that hold the Adjusting Bar to the Pivot Shaft.

do not tighten

BAR

BODY

CAPSCREWS

WARNING!

Prior to removing Pilot system mustbe isolatedfrom pressure. Failure to do so may result in personal injury, environmental spill concerns and/or damage to equipment.

The Pilot (4) is held in place by the Pilot Clamp (36) and four Capscrews (35). Remove theCapscrews, PilotClamp and Pilot from the Control Box. Inspect condition of Gasket (34) and replace if necessry.

Re-install the Pilot, assuring that the Gasket is seated properly with port holes aligned with ports in Pilot and Control Box.

Body Disassembly

Remove the Body from the Control Box as described in the

Disassembly

CAUTION! If the Shaft Retainers (9) are removed, O-Rings (7 and 10) and Back-up Rings (8) MUST BE REPLACED.

Remove the two Shaft Retainers (9) utilizing a 1-1/8” wrench. Remove the Pivot Shaft (6). Remove the Pivot Shaft O-Rings (7), Back-up Rings (8) and Shaft Retainer O-Rings (10) and discard.

section.

General

The Company, L.L.C. Oklahoma City, Oklahoma Tel: (405) 672-6660 Fax: (405) 672-6661

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Page 6

Series

Item Description Qty. Part Number

25 TRU-ARC RING 1 06000-1385 26 FULCRUM, Aluminum 1 05011-4412 27 THUMBSCREW, SS/Plastic 1 06500-5429 28 NYLOC NUT, SS 2 05000-2567 29 ACORN NUT, SS 1 05000-2575 30 DISPLACER ARM - STD., SS 1 06000-1534 30 DISPLACER ARM - VF, SS 1 05011-9296 31 DISPLACER BUSHING, SS 1 06000-5105 32 DISPLACER - STD., PVC 1 05012-3561 33 HINGE PIN, Plated CS 2 06000-7537 34 GASKET, Neoprene 1 06000-4819 35 CAPSCREW, SS 4 05000-5313 36 PILOT CLAMP, SS 1 05012-6325 37 PANEL SCREW, SS 1 06000-1153 38 RETAINER, SS 1 06000-2672 39 SERIAL TAG, Aluminum (not shown) 1 06000-1922 40 THREAD SEAL, Steel/Buna N 1 06000-0395 41 O-RING, Viton® 1 05000-5586 42 BEARING, SS 2 06000-7552 43 TOLERANCE RING, SS 2 06000-7560 44 ADAPTER, VERT. DWN ASSY., SS 1 06500-4350 45 COVER GLASS, Lexan® (not shown) 2 10916 46 COVER GLASS PLATE, SS (not shown) 2 10915 47 COVER GLASS GSKT, Neoprene (not shown) 2 10917 48 SCREW, Plated Steel (not shown) 8 001501P

Item Description Qty. Part Number

1 CONTROL BOX, Die Cast Aluminum 1 05012-4841 2 COVER, Die Cast Aluminum 1 05012-4834 3 BOX SEAL, Neoprene 1 06000-5097 4 SNAP PILOT ASSY., Aluminum & SS 1 06500-5304 4 THROTTLE PILOT ASSY., Aluminum & SS 1 06500-5387 5 BODY, CS 1 05011-4560 6 PIVOT SHAFT, SS 1 05011-4511 7 O-RING, Viton® 2 05000-0769 8 BACK-UP RING, Teflon® 2 06000-1179

9 SHAFT RETAINER, SS 2 05012-9389 10 O-RING, Viton® 2 05000-1155 11 SPACER, SS 1 05011-4495 12 CAPSCREW, SS 2 05000-5578 13 CAPSCREW, SS 1 05000-5453 14 ADJUSTING BAR, Aluminum 1 05011-4438 15 CAPSCREW, SS 2 05000-2526 16 TORQUE BAR, Aluminum 1 05011-4545 17 ADJUSTING SCREW, SS 1 05011-4537 18 JAM NUT, SS 1 05000-2559 19 STUD, SS 1 05011-4552 20 ADJUSTMENT WHEEL, Aluminum 1 05011-4529 21 SPRING, SS 1 06000-4157 22 UPPER GUIDE, Aluminum 1 05011-4479 23 STUD, FLAPPER BAR, SS 2 05012-9371 24 FLAPPER BAR, SS 1 05011-4404

2001NB

The Bearings (42) and Tolerance Rings (43) need not be removed from the Shaft Retainers unless they are damaged and must be replaced.

Body Reassembly

Lightly lubricate new O-Rings and Back-

BACK-UP RING (8)

O-RING (7)

Up Rings with oil. Install Pivot Shaft Back-Up Ring into Shaft Retainers first, with O-Ring next. IMPORTANT! The

Back-Up Ring MUST be outboard of the O-Ring,as illustrated.

255

030

SUPPLY

13 15 29 19

030

OUTPUT

255

SHAFT RETAINER (9)

23 30 31 32

Horizontal Displacer

Thread the Shaft Retainer into theBody.

outboard

Insert the Pivot Shaft into the Body from the inboard side, seating it firmly into the Bearing in the Shaft Retainer on the side

outboard

Re-install the remaining Shaft Retainer over the Pivot Shaft and

threaded into the side of the Body. Tighten both Shaft

inboard

Retainers firmly.

Re-attach the assembledBody tothe ControlBox as described in the

General Reassembly

Assembly

section.

Vertical Displacer

Assembly

Parts List

The Company, L.L.C. Oklahoma City, Oklahoma Tel: (405) 672-6660 Fax: (405) 672-6661

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