tuning fork density transmitterOverview
The SPX504 tuning fork density meter sensor is composed of two piezoelectric crystals, one piezoelectric crystal generates vibration, and the other piezoelectric crystal detects vibration. The tuning fork sensor has a built-in temperature sensor to compensate for the vibration of the piezoelectric crystal. The characteristics are simple structure, convenient use and maintenance, stable and reliable performance. It is a new intelligent instrument developed by itself with independent intellectual property rights. Can be widely used in metallurgy, chemical industry, food, beverage, printing and dyeing, textile, papermaking, petroleum and other production processes, including acid, alkali, salt solution, including the density, concentration of automatic online detection of various solutions. It uses the "resonance" principle of the tuning fork to generate vibration under the drive of the piezoelectric element. Only when the probe is surrounded by the material is the vibration amplitude reduced sharply, resulting in a switching action.
tuning fork density transmitter Working principle
Working based on the vibration principle of components, the component part is the tuning fork part immersed in the measured liquid. The tuning fork part induces vibration through an internal piezoelectric device fixed to the bottom end of the fork body. The oscillation frequency is detected by a secondary piezoelectric device fixed at the other end of the fork, and then the signal is amplified by the circuit on the top. The density of the liquid is closely related to the vibration frequency of the measured liquid when it flows. When the density of the measured liquid changes, the frequency of the vibration when the liquid flows also changes.
Through the following equation, the density of the measured liquid can be accurately calculated:
ρ=K0+K1T+K2T2
In the formula: ρ–liquid density
T–vibration period of sensor output
K0,K1,K2–sensor’s constant, it is calibrated at the factory
tuning fork density transmitter Main Features
The two-wire transmitter with integrated structure is easy to maintain without moving parts.
Four and a half digital LCD display.
Used for fluid or static liquid, suitable for pipeline and tank installation.
The two parameters of temperature and density can be displayed alternately, which is convenient for the conversion of industry standard password.
Continuous online measurement of liquid density without process interruption, can be directly used for production process control.
All parts in contact with liquid are made of several medium stainless steel materials, safe，hygienic
The safe type can be used in hazardous environments; the sanitary type can be installed on the food production site.
installation considerations of tuning fork density transmitter
Flow rates
Maintain constant flow rates and velocities that are within the limits specified for the meter. The fluid flow provides a steady heat flow into the meter installation, and the flow rate influences the self-cleaning of the meter tines, the dissipation of bubbles, and the solid contaminants around the meter. If you install the meter in a bypass configuration (such as in a flow-through chamber), use a pressure drop across an orifice plate in the main process pipe, a pitot scoop arrangement, or a sample pump to maintain flow. When using a sample pump, place the pump upstream from the meter.
Entrained gas
Entrained gas, or gas pockets, can disrupt the measurement of a fluid. A brief disruption in the signal caused by transient gas pockets can be corrected in the meter configuration, but you must avoid more frequent disruptions or serious gas entrainment to ensure accurate and reliable fluid measurement.
To minimize the possibility of entrained gas:
Keep pipelines full of fluid at all times.
Vent any gas prior to the meter installation location.
Avoid sudden pressure drops or temperature changes that may cause dissolved gases to break out of the fluid.
Maintain a back pressure on the system that is sufficient to prevent gas breakout.
Maintain flow velocity at the sensor within the specified limits.
Slurry measurement
To ensure quality measurement when solids are present:
Avoid sudden changes of the fluid velocity that may cause sedimentation.
Install the meter far enough downstream from any pipework configuration that may cause centrifuging of solids (such as at a pipe bend).
Maintain flow velocity at the meter installation that is within the specified limits.
