H75A4/H75VA4
EagleBurgmann | API mechanical seal H75A4 | 2020
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Contents
1. API 682 4th
2. Design requirements of API 682 4th
3. The new type A seal H75A4/VA4
1. Features
2. Operating limits
3. Design
4. Materials
4. Nomenclature
5. The new API code
6. Supply chain
EagleBurgmann | API mechanical seal H75A4 | 2020
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1. API 682 4th - Category overview
API 682
Category 1
Category 2
Category 3
APItex
H75A4,MBS682
,…
H75A4,MBS682,
…
With rigorous data requirements
Mainly
chemical
industry
Petroleum, petrochemical,
refinery and natural gas
industry
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1. API 682 4th – Category 2 & 3
Category 2 & 3 seals are described in the API 682 4th edition as
follows :
 Category 2 & 3 seals are typically intended for use in pump seal
chambers meeting the dimensional requirements of API 610 / ISO
13709 (Table 7, Figure 26).
 Shall be designed for temperatures from -40 °C to 400 °C (-40°F
to 750°F and an gauge pressures up to 40 bar (600 PSI).
 Seals/seal series have to be tested through Seal Qualification
Tests (SQTs).
 Shall be designed for non-hydrocarbon, hydrocarbon and flashing
hydrocarbon applications.
EagleBurgmann | API mechanical seal H75A4 | 2020
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1. API 682 4th – Product Portfolio
EagleBurgmann | API mechanical seal H75A4 | 2020
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2. Design requirements of API 682 4th
Paragraph 6.1.2.6 (Table 1) of the API 682 4th edition which describes minimal clerances of
the mechanical seal design has been revised.
The requirements will be explained on the following pages.
Each deviation has to be agreed and confirmed by the customer and will be shown on the GA
drawing.
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2. Design requirements of API 682 4th
Radial thickness of shaft sleeve
• Minimal radial thickness of sleeves Ts: 2.5 mm (0.10”)
• Minimal radial thickness Th1 of sleeve in the area of component drive set screws:
2.5 mm (0.10”) for shaft < 57 mm
3.8 mm (0.15”) for shaft 57 to 80 mm
5.0 mm (0.20”) for shaft > 80 mm
Th1
Ts
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2. Design requirements of API 682 4th
Minimal radial clearance C1 between rotating and stationary components: 3 mm (0.12“)
Minimal radial clearance C2 in the area of the pumping ring:
0.5 mm (0.020“) for shaft ≤ 60 mm
1.0 mm (0.040”) for shaft > 60 mm
C2
C1
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2. Design requirements of API 682 4th
Minimal radial clearance C3 between ID of the mating ring and OD of the rotating part:
0.5 mm (0.020“) for shaft ≤ 60 mm
1.0 mm (0.040”) for shaft > 60 mm
C3
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2. Design requirements of API 682 4th
Dual seals shall be balanced for inner and outer pressure. (7.2.1.1 & 7.3.1.2)
Standard for springs: multiple, rotating (4.1.3, 6.1.1.2)
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3. The new type A seal H75A4/VA4
1. Features
2. Operating limits
3. Materials
4. Design
EagleBurgmann | API mechanical seal H75A4 | 2020
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3.1 The new type A seal H75A4/VA4 - Features
Improved design based on more than 10.000 delivered seals for API applications in the last 20
years
Same product name will be used since the name is well established world wide
Core parts concept
 Standardized core units for all sizes, on stock as QDP-parts  faster supply chain
 Adaptive hardware can be designed by both headquarters
Optimized core unit design
 Increased robustness due to solid seal ring design
 Identical interface dimensions of IB and OB, H74VA4 core unit = OB of H75A4  better
stock management
 Shorter lengths of core units  higher flexibility to fit the seals into customer seal chambers
 Adaptive hardware is made in 316L  worldwide standard
Seal design meets all requirements of API 682 3rd edition
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3.2 The new type A seal H75A4/VA4 - Operating limits
Parameter
H75VA4
Range
Shaft diameter
d = 20 ... 110 mm (0.79" ... 4.33")*
Process Pressure
p1 = 42 bar (609 PSI)
Max. Δp static
Max. Δp dynamic
63 barg
Δp = p3 – p1
p3 : barrier pressure
20 barg for tandem arrangementp1 : process pressure
42 barg for back-to-back arrangement
H75A4
Temperature
t = -40 °C ... +176 °C (-40 °F … 349 °F)**
Sliding velocity
vg = 23 m/s (75 ft/s)
Axial movement
±1.0 mm (for shaft d  40 mm
±1.5 mm (for shaft d  40 mm
Note: The extremal values of each parameter can not be applied at the same
time due to their interaction. Please refer to application engineering for
requests.
* Other sizes on request
** Engineered up to 260 °C (500 °F) with FFKM (K) secondary seals
Recommended piping plans
Process side
01, 02, 11, 12, 13, 14, 21, 22, 23,
31, 32, 41
Between seals
52, 53A, 53B, 53C, 54, 55
Atmospheric
side
51, 61, 62, 65A, 65B, 66A, 66B
H75A4: Inboard seal in Double arrangements for outside (Plan 52) and inside
(Plan 53) pressurization with full design pressure. Balanced in both pressure
directions.
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3.3 The new type A seal H75A4/VA4 - Materials
Seal part
API 682 compliant
Seal ring
A, Q2 (Q1 for caustics)
Mating ring
Q1, Q2
Secondary Seals
EPDM (E), NBR (P), FKM (V),
FFKM (K)
Springs
M5 (Hastelloy C-276)
Components
G (316L / 1.4404)
Other materials on request.
Prices and delivery times will differ for nonstandard seals.
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3.4 The new type A seal H75A4/VA4 - Design - Core parts
concept
Seal Cavity
Core Seal Parts
Standard Parts
Shaft Sleeve
(Adaptive Part)
Housing
(Adaptive Part)
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3.4 The new type A seal H75A4 - Design - Core parts
Solid carbon ring
for optimized control of
deformation in extreme conditions
with variable pressure and
temperature
Rotating
multiple
springs
Balanced from outer and inner
side
API Plan 52 & 53 supplied with identical seal
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face
design
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3.4 The new type A (outboard) seal H75VA4 - Design - Core parts
Solid carbon ring with radial back up
ring
for optimized control of deformation
and small radial height
Rotating
multiple
springs
Optimized Seal Face
Width
Bi-directional
for low friction
circulation device
losses
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3.4 The new type A seal H75A4-B - Design - Core parts
Seal ring and mating
ring from H75A4
balanced from outer
and inner side
Seal ring and
mating ring from
H75VA4
small radial height
One common driver
for a minimized
design
EagleBurgmann | API mechanical seal H75A4 | 2020
Bi-directional
circulation device
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3.4 The new type A seal H75VA4/A4 - Design features
Integral flush
(Multipoint)
Modular
Driver
Floating Throttle
Bush
Single Seal (H75VA4)
Optimized segmentation of
cover
(intersections not interfering with
connections)
Pump ring for
Plan 23
available
(optional)
Mechanical
retaining of
Mating Ring
EagleBurgmann | API mechanical seal H75A4 | 2020
Throttle Bush
(optional)
Double Seal (H75A4)
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3.4 The new type A seal H75A4/VA4 - Design materials
SS 316L
SS
316L
Alloy Steel
(coated)
1.4462
A4-70
Springs:
Hastelloy® C-276
(M5)
SS
316L
SS 316L
EPDM (E), NBR
(P), FKM (V), FFKM
(K)
Silicon carbide
SSiC (Q1),
RBSiC (Q2)
SS 316L
Blister resistant carbon
(A),
Silicon carbide SSiC (Q1),
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RBSiC (Q2)
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4. Nomenclature
Single seal:
Dual seal:
H75VA4-S
H75A4-T
H75A4-B
(standard with plan 11 and 61)
(standard with LBI and LBO for plan 52 / 53ABC / 54 /55)
(standard with LBI and LBO for plan 53ABC / 54)
S = Single
T = Face-to-back (“tandem”) arrangement
B = Back-to-back arrangement
New drawing number
For the new H75A4/VA4 series a new drawing code is used. The number following the seal type
shows the diameter of the pump shaft. Example:
H75A4-070-B0D4-DE001A1  shaft diameter = 70 mm
The seals can be equipped with the following API plans:
• Process side:
• Between seals:
• Atmospheric side:
01, 02, 03, 11, 12, 13, 14, 21, 22, 23, 31, 32, 41
52, 53A, 53B, 53C, 54, 55
61, 62, 65A, 65B, 66A, 66B
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5. The new API code
Example: New code
23A-PFN-070-11/53B
Old code
C2A3A1153B
(material AQ2V** )
Our seal for this application: H75A4-T or H75A4-B
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6. Supply chain – where to order
The above chart shows the current availability of mechanical seals.
Further design and manufacturing hubs will be qualified according to the global EagleBurgmann strategy
Delivery times according ETO lead time table.
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Thank you for
your attention!
Questions?
Learn more about EagleBurgmann
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