A02 New DOR_P8FDR_EPC.pdf

Description of Requirement

Requirement

Earth pressure cells shall meet the following requirements.

The required earth pressure cells are the hydraulic type. They consist of two stainless flat plates welded together around their periphery to leave a narrow space between them. This space is filled with a de-aired hydraulic oil that is connected hydraulically to a pressure transducer where the oil pressure is converted to an electrical signal which is transmitted through a signal cable to the readout location. Shown in Figure 1 is the schematic for the required earth pressure cell. The earth pressure cell must also meet the following requirements:

Figure 1. Schematic of required earth pressure cell.

• Performance:

a. Over Range: (1.5) x (Rated Pressure)

b. Resolution: Infinite

c. Fatigue Life: Designed for more than 100 Million Full Scale (FS) Cycles

d. Long Term Drift: 0.20% FS/Year (Noncumulative)

e. Accuracy: ± 0.25% FS

f. Thermal Error: ± 1.50% FS

g. Operating Temperature Range: [-20 to 80] °C

h. Zero Tolerance: ± 1.00% of Span

i. Span Tolerance: ± 1.00% of Span

j. Warranty: Minimum 12-Months After Delivery To ERDC Customer

• Mechanical Configuration:

a. Wetted Parts: 17-4 PH Stainless Steel

b. Enclosure: 316 ss, 17-4 PH ss

c. Plate Geometry:

i. Circular Plate Diameter (D) = 230-mm.

ii. 2-Welded Plate Stainless Steel Composite Thickness = Diameter-To-Thickness Aspect Ratio of 20:1

d. Fluid Media: Hydraulic Oil De-Aired using Nold DeAerator™

e. Transducer:

i. Semiconductor Transducer

ii. Bonded Resistance Strain Gauge

iii. Transducer Housing Attached Via 17-4 PH Stainless Steel Tubing

iv. Capable of Providing Low Level Output

f. O-Rings: Not Allowed For Confinement of Fluid Media

g. Vibration Resistance: 35 g peak Sinusoidal, 5 to 2000 Hz

h. Acceleration Resistance: 100 G Steady Acceleration In Any Direction 0.032% FS/g For 1-Bar (15-Psi)

Range Decreasing Logarithmically To 0.0007% FS/G For 400-Bar (6000-Psi) Range

i. Shock Resistance: Withstands Free Fall In Accordance ANSI Standard IEC 88-2-32 Procedure 1

j. Cable:

i. Water Resistant

ii. Four Individually Shielded Pairs

iii. Two Pair Connected to Semiconductor Bridge

iv. One Pair Connected Remote Sense

v. One Pair Connected Thermistor

k. Weight Approximately: 100 g + 75 g/m cable

• Electrical Response:

l. Output : 100-mV ± 1-mV

m. Supply Voltage (VS): 10-Vdc (15-Vdc max.) Regulated

n. Bridge Resistance: [2600 to 6000] ohms

Bidder Qualifications:

a. Either Manufacture or Approved/Registered By Manufacture as Primary or Reseller of Specified Earth

Pressure Cells.

b. Provides Direct In-House After Sale Technical Support by Phone and Email of Specified Earth Pressure Cells.

Earth Pressure Cell (EPC) Type and Quantities:

Table 1. Summary of required EPC quantity and measurement ranges.

Measurement Range Quantity

2.5 mPa full scale (362 psi) 31

1.0 mPa full scale (145 psi) 31

700 kPa full scale (101 psi) 15

400 kPa full scale (58 psi) 45

Additional Technical Documents Included In Contract Submittal Requirements:

a. Signed Letter on Manufactures Letterhead That Identifies the Submitter By Business Name As An

Approved/Registered as Primary or Reseller of Specified Earth Pressure Cells.

b. Signed Letter on Submitter’s Letterhead Indicating the Ability To Provide Direct In-House After Sale

Technical Support by Phone and Email of Specified Earth Pressure Cells.

c. Example of Typical Calibration Reports That Meets The Provided Specifications.

d. Example of Pressure Calculations That Meets The Provided Specifications.

e. Example of Thermistor Derivation, Equation, and Look-Up Tables That Meets The Provided

Specifications.

f. Wiring Charts/Tables That Meets The Provided Specifications.

g. Documentation of Temperature/Barometric Effects On Earth Pressure Cells For Specified Earth

Pressure Cells.

Shipping Costs:

Must Be Included In Quote.

EPC Delivery Date:

No Later Than 30 NOV 2023.

Point of Contact and Delivery Location:

GSL-Airfields and Pavements Branch

CEERD-GMR/GMA

3909 Halls Ferry Rd

Vicksburg, MS 39180-6199