Emerson Y690A Data Sheet

Bulletin 74.1:Y690A

Y690A Series Gas Blanketing Regulators

W7293

January 2010

Figure 1. Y690A Series Direct-Operated Gas Blanketing Regulators

Features

• Easy Conversion Between Constructions—

Converts easily from Type Y690A to Type Y690AM
with two O-rings and one machine screw.

• Sour Gas Service Capability—For sour gas
applications, the Y690A Series regulators are
available in materials that comply with National
Association of Corrosion Engineers (NACE)
Standards MR0175 and MR0103.

• Inlet Pressure Equals Outlet Pressure—Full
inlet pressure capability on the downstream side
of the regulator.

• Corrosion Resistance—Multiple regulator
constructions are available in a variety of materials
for compatibility with corrosive process gases.

• Multiple Applications—Y690A Series can be used
for a wide variety of gases including air, nitrogen,
natural gas, sour gas, butane, and propane.

Introduction

The Y690A Series Gas Blanketing Regulator System
reduces a high-pressure gas, such as nitrogen,
to maintain a protective environment above any
liquid stored in a tank or vessel. The regulator
system replaces the volume of vapors with a
volume of blanketing gas to prevent the internal
vessel pressure from decreasing, when liquid is
being pumped out or when the vessel is suddenly
cooled, causing vapors to contract. In both cases
a slight positive vessel pressure prevents outside
air, moisture and other contaminants from entering
the vessel. Type Y690A (Figure 1) is a direct-operated
regulator used for accurate pressure control on very
low-pressure blanketing systems. Downstream
pressure is sensed through a pitot tube installed in
the lower casing of the regulator, thus no external
control line is required. Type Y690AM uses a
control line to more accurately control the pressure
if the regulator is mounted away from the tank.

www.sherregulators.com

D102591X012

Bulletin 74.1:Y690A

Specications

Available Congurations

Type Y690A: Direct-operated pressure reducing

regulator for outlet pressures up to 7-inches w.c.
(17 mbar) equipped with a pitot tube for greater
regulated capacities.

Type Y690AH: Direct-operated pressure
reducing regulator for outlet pressures up to
7 psig (0,48 bar) equipped with a pitot tube for
greater regulated capacities.

Type Y690AM: Direct-operated pressure
reducing regulator for outlet pressures up to
7-inches w.c. (17 mbar) equipped with a
blocked throat and O-ring stem seal. The
lower diaphragm casing is tapped 1/2 NPT for
control line connection.

Type Y690AHM: Direct-operated pressure
reducing regulator for outlet pressures up to
7 psig (0,48 bar) equipped with a blocked
throat and O-ring stem seal. The lower
diaphragm casing is tapped 1/2 NPT for
control line connection.

Body Sizes

NPS 3/4 or 1 (DN 20 or 25)

End Connection Styles

See Table 1

Maximum Allowable Inlet Pressure

(1)

150 psig (10,3 bar)

Maximum Operating Inlet Pressure

(1)

See Table 4

Maximum Outlet Pressure (Casing)

(1)

150 psig (10,3 bar)

Maximum Emergency Outlet Pressure to Avoid
Internal Parts Damage

(1)

150 psig (10,3 bar)

Outlet Pressure Ranges

(1)

See Table 5

Orice Sizes and Flow and Sizing Coefcients

See Table 2

Pressure Registration
Types Y690A and Y690AH: Internal
Types Y690AM and Y690AHM: External

Flow Capacities

See Tables 9 and 10

Construction Materials

See Table 3

Material Temperature Capabilities

(1)

Nitrile (NBR):

-20° to 180°F (-29° to 82°C)

Fluorocarbon (FKM):

40° to 300°F (4° to 149°C)

Ethylenepropylene (EPDM):

-20° to 275°F (-29° to 135°C)

Peruoroelastomer (FFKM):

-20° to 300°F (-29° to 149°C)

Pressure Setting Adjustment

Adjusting Screw

Spring Case Connection

1/4 NPT

Diaphragm Case Connection

1/2 NPT

Approximate Weight

19 pounds (9 kg)

1. The pressure/temperature limits in this Bulletin and any applicable standard or code limitation should not be exceeded.

2

Table 1. End Connection Styles

Bulletin 74.1:Y690A

BODY SIZE,

NPS (DN)

3/4 or 1

(20 or 25)

Ductile Iron Stainless Steel

NPT

END CONNECTION STYLE

Table 2. Orice Sizes and Flow and Sizing Coefcients

ORIFICE SIZE,

INCHES (mm)

1/8

(3,2)

1/4

(6,4)

3/8

(9,5)

1/2

(13)

9/16

(14)

WIDE-OPEN FOR RELIEF

VALVE SIZING

C

12.3
50

110
200
250

g

C

0.35

1.43

3.14

5.71

7.14

V

C

1

35 0.78 0.50 0.89

IEC SIZING COEFFICIENTS

X

T

Table 3. Construction Materials

BODY DIAPHRAGM CASE SPRING CASE TRIM DIAPHRAGM DISK

Nitrile (NBR),

Ductile iron or

CF8M Stainless steel

Ductile iron or

CF8M Stainless steel

Ductile iron or

CF8M Stainless steel

303 Stainless steel,

316 Stainless steel

Fluorocarbon (FKM), or
Polytetrauoroethylene

(PTFE) bonded

Nitrile (NBR)

NPT, SWE,

CL150 RF,

CL300 RF, or

PN 16/25/40

F

D

F

L

Nitrile (NBR),

Fluorocarbon (FKM),

Peruoroelastomer (FFKM),

PTFE, or

Ethylenepropylene (EPDM)

Table 4. Maximum Operating Inlet Pressures in Psig (bar)

OUTLET PRESSURE RANGES

ORIFICE

SIZE,

INCHES (mm)

2.5-Inches w.c.

Type Y690A Types Y690AH and Y690AM

1 to

(2 to 6 mbar)

2.5 to

7-Inches w.c.

(6 to 17 mbar)

5 to

10-Inches w.c.

(12 to 25 mbar)

7 to

16-Inches w.c.

(17 to 40 mbar)

15-Inches w.c.

to 1.2 Psig

(37 to 83 mbar)

1.2 to 2.5 Psig
(83 mbar

to 0,17 bar)

2.5 to 4.5 Psig

(0,17 to 0,31 bar)

4.5 to 7 Psig

(0,31 to 0,48 bar)

1/8 (3,2) 150 (10,3) 150 (10,3) 150 (10,3) 150 (10,3) 150 (10,3) 150 (10,3) 150 (10,3) 150 (10,3)

1/4
3/8

1/2

9/16

(6,4)
(9,5)

(13)
(14)

40
20

10

5

(2,8)
(1,4)

(0,69)
(0,34)

60
20

10

5

(4,1)
(1,4)

(0,69)
(0,34)

75
35

8
5

(5,2)
(2,4)

(0,55)
(0,34)

75
35

8
5

(5,2)
(2,4)

(0,55)
(0,34)

75
35

8
5

(5,2)
(2,4)

(0,55)
(0,34)

150

60

10

6

(10,3)
(4,1)

(0,69)
(0,41)

150

60

12

8

(10,3)
(4,1)

(0,83)
(0,55)

150

Table 5. Outlet (Control) Pressure Ranges and Spring Part Numbers

TYPES

Y690A and

Y690AM

Y690AH and

15-inches w.c. to 1.2 psig

Y690AHM

1. To achieve the published outlet pressure range the spring case must be installed pointing down.

2. Do not use uorocarbon (FKM) diaphragm with this spring at diaphragm temperatures lower than 60°F (16°C).

OUTLET (CONTROL)

PRESSURE RANGE

1 to 2.5-inches w.c.

2.5 to 7-inches w.c.

5 to 10-inches w.c.
7 to 16-inches w.c.

1.2 to 2.5 psig

2.5 to 4.5 psig

4.5 to 7 psig

(2 to 6 mbar)
(6 to 17 mbar)

(12 to 25 mbar)
(17 to 40 mbar)
(37 to 83 mbar)

(83 mbar to 0,17 bar)
(0,17 to 0,31 bar)
(0,31 to 0,48 bar)

SPRING PART

NUMBER

1B558527052

1B653827052

1B653827052
1B653927022
1B537027052

1B537127022
1B537227022
1B537327052

(1)(2)

(1)

SPRING

COLOR

Orange

Red

Red

Unpainted

Yellow

Light green

Light blue

Black

SPRING WIRE DIAMETER,

INCHES (mm)

0.072

(1,83)

0.085

(2,16)

0.085

(2,16)

0.105

(2,67)

0.114

(2,90)

0.156

(3,96)

0.187

(4,75)

0.218

(5,54)

SPRING FREE LENGTH,

INCHES (mm)

3.78 (96,0)

3.63 (92,2)

3.63 (92,2)

3.75 (95,2)

4.31 (109)

4.06 (103)

3.94 (100)

3.98 (101)

60

12

8

(10,3)
(4,1)

(0,83)
(0,55)

3

Bulletin 74.1:Y690A

VALVE DISK

PITOT TUBE FOR
TYPES Y690A
AND Y690AH

INLET PRESSURE

OUTLET PRESSURE

ATMOSPHERIC PRESSURE

B2625

Figure 2. Y690A Series Operational Schematic

VALVE STEM

SLIDING PUSHER POST

DOWNSTREAM CONTROL LINE FOR
TYPES Y690AM AND Y690AHM

LEVER

OVERPRESSURE SPRING

Principle of Operation

With Internal Registration
(Refer to Figure 3)

Types Y690A and Y690AH are direct-operated
regulators with internal registration (see Figures 2
and 3). It provides a constant set pressure for
accurate gas blanketing. When vessel pressure
decreases below the control spring setpoint, the force
of the spring moves the disk away from the orice
allowing gas to ow into the vessel. As the vessel
pressure increases, the increase is sensed by the
diaphragm through the pitot tube. This movement
of the diaphragm causes the disk to move toward the
orice, decreasing the ow of blanketing gas. When
the vessel pressure reaches the system setpoint,
the disk will seat against the orice shutting off the
ow of gas.

With External Registration
(Refer to Figure 4)

Types Y690AM and Y690AHM Gas Blanketing
Regulators reduce a higher-pressure gas to maintain
a positive low pressure of blanket gas over a stored
liquid. Also when the vessel (or tank) is suddenly
cooled, causing vapors to contract, the regulator

replaces the volume of contracting vapors with a
volume of blanketing gas to prevent the internal vessel
pressure from decreasing. In both cases, a positive
vessel pressure prevents outside air from entering the
vessel and reduces the possibility of atmospheric
pressure collapsing the vessel.

Gas blanketing regulators respond to a slight decrease
in internal vessel pressure (caused by pump out or
atmospheric cooling) by throttling open to increase the
ow rate of gas into the vessel. When the vessel’s
liquid level has been lowered to the desired point
and the vapor pressure has been reestablished, the
regulator throttles close.

When the liquid level drops and vessel pressure
decreases below the setting of the control spring,
the spring force on the diaphragm opens the disk
assembly to supply the required ow of gas to the
vessel. When vessel pressure has been satised,
outlet pressure tends to increase slightly, acting on
the diaphragm. When the outlet pressure exceeds
the control spring setting, the diaphragm moves to
close the disk assembly.

4

INLET PRESSURE

GAS BLANKETING PRESSURE

ATMOSPHERIC PRESSURE

BLOCK

VALVE

VENT

VALVE

SUPPLY

PRESSURE

GAS BLANKETING PRESSURE

VESSEL/TANK

VENT

VALVE

BLOCK

VALVE

Bulletin 74.1:Y690A

Figure 3. Type Y690A or Y690AH with Internal Registration Operational Schematic

VENT

VALVE

BLOCK

VALVE

VENT

VALVE

INLET PRESSURE

GAS BLANKETING PRESSURE

ATMOSPHERIC PRESSURE

BLOCK

VALVE

GAS BLANKETING PRESSURE

VENT POINTED DOWN

VESSEL/TANK

VENT

VALVE

BLOCK

VALVE

Figure 4. Type Y690AM or Y690AHM Gas Blanketing Regulator with External Registration Operational Schematic

5