Fork Insertion Type Density Meter


RBDM Fork Insertion liquid Density Meter is based on the proven tuning fork technology. It is an all-welded sensor that is designed for insertion into a pipeline, open tank, or closed tank.

Fluid density is determined directly from the resonant frequency of the tuning fork immersed in the fluid. A temperature sensor is also fitted within the transmitter to indicate the operating temperature.

The fork plug-in density meter is a versatile instrument that finds wide application in various industrial fields. Its accurate and reliable measurement capabilities make it an essential tool in ensuring quality control and process optimization.

In the petroleum industry, density measurement is crucial for assessing the quality and purity of various petroleum products. The fork plug-in density meter can be used to measure the density of crude oil, refined petroleum products, and natural gas. This information is essential for maintaining product consistency and determining the energy content of fuels.

In the pharmaceutical industry, the density meter is utilized for measuring the concentration and purity of liquid drugs and solutions. It ensures that medication formulations are precisely mixed and meet regulatory requirements.

In the food and beverage industry, the density meter is employed for measuring the sugar content, alcohol concentration, and overall quality of beverages. It is also used in the dairy industry to measure the fat content in milk products.

The tuning fork plug-in density meter can also be applied in the chemical industry for monitoring the density of various chemicals and solutions. This is vital for ensuring accurate dosing and mixing in chemical processes.

Additionally, the density meter is used in the mining and metallurgical industries to determine the density of ores and minerals. This information allows for efficient processing and separation of valuable materials.

Overall, the wide application of the tuning fork plug-in density meter in the industrial field is a testament to its importance in achieving precise measurements, maintaining quality control, and optimizing various industrial processes.






  • Principle
  • Features
  • Specification
  • Model Selection
  • Applicants
  • Download

RBDM Insertion Density Meter operates on the vibrating element principle, the element in this case being a tuning fork structure that is immersed in the liquid being measured. The tuning fork is excited into oscillation by a piezoelectric device internally, secured at the root of one tine. The frequency of vibration is detected by a second piezoelectric device, which is secured in the root of the other tine.

The meter sensor is maintained at its natural resonant frequency, as modified by the surrounding liquid, by an amplifier circuit located in the electronic housing. This frequency of vibration is a function of the overall mass of the tine element and the density of the liquid in contact with it. As the density of the liquid changes, the overall vibrating mass changes, and therefore the resonant frequency changes.

By measuring this frequency and applying the following equation, the density of the liquid can be calculated.


ρ = K0 + K1τ + K2τ2


• ρ = Fluid uncorrected density (kg/m3)

• τ = Time period of meter (μs)

• K0, K1, K2 = meter calibration coefficients


RBDM Fork Insertion Density Meter Features:

  • For pipe size is more than DN150
  • Maintenance is minimal and reduces overall operating costs
  • fully integrates digital density measurement for monitoring and control
  • Capable of direct insertion into large bore pipe work applications, substantially reducing the installation cost compared to flow through devices
  • Tolerant of applications where high fluid viscosity exists

RBDM Fork Insertion Density Meter Specifications

Density range

0.5 – 2.5 g /cc (500 – 2500 kg/m3)

Calibration range

0.8 – 1.2 g /cc (800 – 1200 kg/m3)


± 0.002 g /cc (± 2 kg/m3);± 0.001 g /cc (± 1 kg/m3)


± 0.0002 g /cc (± 0.2 kg/m3)

Temperature range (Process)

-20 ~ +150 Degree Celsius (℃)

Pressure rating

10MPa  ~  20MPa

Viscosity range

0 – 20000 cP

Temperature effect

Less than 0.1 kg/m3/℃ (After Calibration)

Impact from pressure


Built-in temperature sensor


Wetted parts

Stainless steel 316L/ HC Hastelloy

Tine finish

Standard, PFA coated, or Electro-polished

Power supply

24VDC,≥500 mA

Analog Output

4 -20 mA,0-1000Hz,RS485 Modbus RTU

Density accuracy - process(20)

± 0.1% or ± 0.05% FS of indicated figures

Repeatability - process(-40 ~85)

± 0.05% FS

Process connection

ANSI 150 ~ 1500 RF

DIN 50 PN16  DIN 50 PN40

IDF and RJT hygienic type

Protection Grade


Outer covering

Aluminum alloy

Model Selection

RBDM Insertion liquid Density Meter Model selection


RBDM Fork Insertion Density Meter Model selection
Code Production
RBDM RBDM-CR Liquid Insertion Density Meter
  Code Probe Rob Material
A 316 Stainless Steel Standard
B HC Hastelloy Standard
D Titanium alloy
E Zirconium
F Tantalum
G Monel alloy
H Super Austenitic stainless steel
I C4 steel
J Overall lining PFA or PTFE
X Special custom
  Code Flange Material
A The material of the whole flange is the same as that of the probe rod
B The material of the lower end of the flange is the same as that of the probe rod
C Special custom
  Code Power supply
A 220VAC
  Code Pressure Class
16 1.6MPa
40 4.0MPa
XX Requested preference:Please inform for particular requirement
  Code Process Connection
1 DN50 HG/T 20592-2009RF
2 Tri-clamp Connection
X Special custom
  Code Length
128 Standard length 128mm
XXX Special length
  Code Installation Method
A(xx) Horizontal Pipeline Insertion (X=pipe line)
B(xx) Variable Installation Pipe (X=pipe line size)
C Tank Insertion
D Please inform for particular requirement
  Code Transmitter output
C 4-20mA 0-1000Hz RS485 Modbus RTU
  Code Transmitter housing
F Aluminum Alloy
  Code Factory Setting
G Factory Setting Options
RBDM-CR A  A  D 16 1 128 A-200 A F G Typical Model Selection
 1. Ex-proof design;. 




RBDM Fork Insertion liquid Density Meter Application

RBDM Insertion Density Meter is ideally suited to applications where continuous, real-time measurement of density is required. As an instance, it can be used in process control where density is the primary control parameter for the end product, or functioning as an indicator of some other quality control parameter such as percent solids, or percent concentration.

RBDM Insertion Density Meter
can be applied widely in numerous industries, including brewing, end point detection in batch reactions, evaporator control, petroleum retail outlets, product mixing, slurries, tank and pipe applications, and solvent separation.


Catalog - Insertion type density meter

Manual - Density meter

Other files - Density measurement

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