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Bermad Model 900 - Basic Hydrometer

The BERMAD Model WW-900 is a unique product integrating both a Woltman-type water meter and a diaphragm actuated hydraulic control valve, both functions working simultaneously. A water meter, providing a full spectrum of metering functions, from simple visual readout, with pulse or analog 4 – 20 mA output for computerized data acquisition ideal for SCADA systems. A standalone hydraulic valve with a full range of control features; On/Off, pressure reducing, sustaining, flow and level control.


Features and Benefits

  • The flow metering unit is perpendicular to the pipeline and includes integral inlet and outlet flow straighteners. This internal design eliminates the need for straightening distances before and after the valve, saving valuable space especially in pit installations, this unique design enables vertical or horizontal installation whilst ensuring accuracy even when the valve is partially open during pressure or flow control tasks.
  • Designed with a highly sensitive magnetic drive that provides superior accuracy meeting most water meter standards
  • The available Reed Switch and Opto-Electric 4-20 mA transmitter and pulse options provide flexibility in electrical pulse generation.
  • The cover is easily unbolted for quick in-line inspection and service. All the internal assemblies can be easily removed from the valve body with no need for disassembling the valve from the line.
  • A carefully balanced and peripherally supported diaphragm eliminates stress distortion, resulting in long-life and controlled actuation even under harsh conditions. One diaphragm and spring meets most of the the valve’s operating pressure range requirements.
  • The impeller drive is magnetically coupled to a vacuum-sealed meter register in the control head. Both the magnetic drive control head and its register(s) are hermetically sealed and are not affected by dirty water or environmental humidity.
  • The series is designed to be suitable for metering and control applications in pressure management systems for effective leakage reduction.
  • Advanced hydraulic design combines simple and reliable construction with superior performance and a remarkable cavitation resistance.


3-Way Cock Valve Local Manual Control

Line pressure is applied to the control chamber of the hydrometer through the opened 3-way solenoid or cock valve. This creates superior hydraulic force in the control chamber that causes the valve to close and seal drip tight.

Solenoid Controlled

Closing the Solenoid or cock valve, discharges the line pressure from the control chamber. This in turn causes the line pressure under the plug to open the valve, and measure the flow.

2-Way Modulating Mode; Pressure Reducing Pilot

Exploded View

[1] Control Head

Includes: Vacuum-sealed meter register, magnetically coupled to the impeller drive, with robust brass cover. Hermetically sealed control head and register(s). High sensitivity, providing superior accuracy that meets most water meter standards. Available of Reed Switch and Opto-Electric pulse readers (4 - 20mA optional with converter).

[2] Valve Cover

Locates, centralizes and fastens diaphragm, spring, and impeller assembly ensuring smooth and accurate performance. Simple and light construction enables quick in-line inspection and service.

[3] Auxiliary Closing Spring

Various springs are available to meet different requirements.

[4] Closure Assembly

Combining a rugged radial disk harnessed to a flexible fiber reinforced diaphragm. The fully guided closure assembly and the carefully balanced and peripherally supported diaphragm prevent distortion and protect the elastomer, resulting in long-life and controlled actuation even under harsh conditions.

[5] Lower Flow Staightener Assembly

[5.1] Guide – Carries the transmission shaft, guides the closure assembly, and centralizes and tightens all internal parts.

[5.2] Upper Flow Straightener – Tightens the seal seat in place, straightens outlet flow, and creates mushroom-shaped flow.

[5.3] Impeller – Woltman-type impeller with tungsten carbide shaft tips and bearings for high, long-term accuracy and negligible wear.

[6] Impeller Housing

[6.1] Seal Seat – Metal ring vulcanized with elastomeric seal, raised and distanced from valve body to prevent cavitation damage.

[6.2] Integral V-Port for smooth regulation and closing charateristics.

[6.3] Lower Flow Straightener – Straightens inlet flow, eliminating the need for straight upstream pipe required in standard water meters.

[7] Integrated Calibration Device

Enables recalibration instead of renovation when the recommended standard accuracy period has elapsed (The Calibration Device is closed with a seal).

[8] Wide Body

Hydro-dynamically designed for efficient flow with minimal pressure loss and excellent resistance to cavitation. End Connections conform to pressure ratings and standards: ISO, ANSI, JIS, BS, and others.

Construction Materials

[1] Control Head:
Copper, Brass Reinforced Nylon, and Glass

[2] Cover: Epoxy Coated Ductile Iron to EN 1563

[3] External Bolts / Nuts: Stainless Steel 316

[4] Internal Bolts, Nuts and Washers: Stainless Steel 304 and 316

[5] Spring: Stainless Steel 302

[6] Closure Assembly:
[6.1] Diaphragm: Synthetic Rubber
[6.2] Closure: Glass Reinforced Nylon
[6.3] V-Port: Stainless Steel 304

[7] Impeller Assembly:
[7.1] Guide: 2” Pa12, 3&4” PVDF, 6-10” 303 Stainless Steel
[7.2] Pivots, Bearings, and Thrust Bearings: Tungsten Carbide
[7.3] Upper flow Straightener: Glass Fiber Reinforced Nylon
[7.4] Impeller: Polypropylene

[8] Impeller Housing Assembly:
[8.1] Seal Seat: Synthetic Rubber
[8.2] Impeller Housing and Lower Flow Straightener: Glass Fiber Reinforced Nylon

[9] Valve Body: Epoxy Coated Ductile Iron to EN 1563

O-Rings: Synthetic Rubber

Coating: Epoxy Fusion Bonded, Blue, 250 micron

Technical Specifications

Available Sizes:

DN40 - DN250 (1½” - 10”)

Pattern: Globe

End Connections:

DN40 - DN50 (1½” - 2”) - Threaded

DN80 - DN250 (1½” - 10”) - Flanged

DN80 - DN150 (1½” - 6") - Grooved

Connections Standard:

Flanged: ISO 7005-2 (PN10 & 16, other standards available)

Threaded: Rp ISO 7/1 (BSP.P) or NPT

Pressure Rating: PN16

Operating Pressure Ranges:

PN10: 0.7-10 bar

PN16: 0.7-16 bar

For lower pressure requirements, please contact us


Water up to 50°C

Pulse Electric Data:

Reed-Switch: Switching voltage: 48 VAC/DC max

Switching current: 0.2A max

Switching power: 4W max

Opto-Electric: Supply voltage: 5-12 VDC

Output type: complementary

Output current: 200 mA

Analog Output: Supply Voltage 24VDC

Output: 4-20mA

Input: Opto-Electric

Accuracy Table

Flow Chart - 900 (V Port)

PDF Datasheets

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2D CAD Drawing

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Product code

Bermad Model 900 - Basic Hydrometer

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