SI-3151TLT Diaphragm Pressure Transmitter-Flange Type

SI-3151TLT Diaphragm Pressure Transmitter-Flange Type

The Diaphragm Pressure Transmitter uses the isolation diaphragm box as the measuring part and is installed with a flange. Pressure transmitter diaphragm seals are used to protect pressure measuring instruments from corrosive, viscous, crystallizing, aggressive, highly viscous, environmentally hazardous and toxic media.

SI-3151TLT Diaphragm Pressure Transmitter-Flange Type is mainly used to measure high temperature, easy to solidify or crystallize, contain suspended solids, too viscous, corrosive or other media that need to maintain hygienic conditions and cannot be polluted.

Features of SI-3151TLT Diaphragm Pressure Transmitter-Flange Type

  • The isolation diaphragm is available in a variety of materials and has a high level of corrosion resistance
  • Easy to clean, hygienic, no dead ends
  • The electronic shell is made of aluminum alloy, and the shell protection level is IP65
  • On-site display, output 4~20mADC at the same time, can superimpose HART protocol
  • Zero and full scale adjustable
  • It can be used for a wide range of tested media, including oil, water and paste compatible with 316 stainless steel and 304 stainless steel.
  • High accuracy, high stability, imported original sensor, good linearity, high temperature stability.
  • The pressure sensor directly senses the pressure of the measured liquid level, and is not affected by the foaming and deposition of the medium.

SI-3151TLT Diaphragm Pressure Transmitter Specifications

Range: -100KPa~0~60MPa;
Accuracy:0.25%FS, 0.5%FS
Output signal: 4 ~ 20mA (two-wire system);
Power supply voltage: 9~36VDC (two-wire system), 9~40VDC (three-wire system);
Medium temperature: -30℃~+85℃;
Ambient temperature: -20℃~+85℃;
Allowable overload: 150%FS;
Temperature drift: ≤±0.05%FS/10℃;
Stability: ±0.1%FS/year~±0.2%FS/year;
Pressure port: M20×1.5, G1/4, 1/4NPT and other external threads or customized according to user requirements;
Electrical interface: Four-core shielded cable (protection grade IP65), aviation plug, DIN connector;

Diaphragm Pressure Transmitters

SI-3151TLT Diaphragm Pressure Transmitter-Flange Type Applications

Diaphragm Pressure Transmitter can be used in various industries. Including chemical coatings, paint detection systems; environmental protection, coal mines; sealed oil pressure systems, experiments or testing equipment; mud, coal slurry, crude oil and other viscous media.

The flanged Diaphragm Pressure Transmitter is suitable for the following measurements:

Diaphragm Pressure Transmitter Specifications
  1. Viscous medium at high temperature;
  2. Medium that is easy to crystallize;
  3. Sedimentary media with solid particles or suspended matter;
  4. Strong corrosive or highly toxic medium;
  5. It can eliminate the occurrence of the leakage of the pressure guiding tube and pollute the surrounding environment. It can avoid the tedious work of frequently replenishing the spacer because of the instability of the measurement signal when the spacer is used;
  6. Continuous and accurate measurement of interface and density;
  7. The remote transmission device can avoid the mixing of different instantaneous media, so that the measurement results truly reflect the actual situation of the process change;
  8. Occasions with high requirements for sanitation and cleanliness;
  9. For example, in the production of food, beverage and pharmaceutical industries, it is not only required that the parts of the transmitter in contact with the medium meet the hygienic standards. And it should be easy to rinse. To prevent cross-contamination of different batches of media.

Order Guide

SI-3151TLT  Diaphragm Pressure Transmitter
B Standard type
J Compact type
T Ceramic capacitive Type
Range A 0-5KPa-20KPa E 0-0.7MPa-3.5MPa
B 0-20KPa-70KPa F 0-2.0MPa-7MPa
C 0-70KPa-350KPa G 0-7MPa-35MPa
D 0-200KPa-700KPa H 0-20MPa-100MPa
Display 1 no display
2 Digital display
3 LCD  Display
Installation M M20*1.5 external thread
MF Diaphragm type (mark: flange specification + diaphragm materia)
O Other specifications (please mark)
output signal E 420mA two-wire system (DC 24V)
K 020mA
M user agreement
Explosion-proof 0 Non-explosion-proof
i Intrinsically safe type iaⅡCT6
d Flameproof dBT4
Additional options Damping adjustment
absolute pressure measurement
negative pressure measurement
Select ceramic sensor
Heat sinks and process connections
user agreement


Diaphragm seals (also known as chemical seals or remote seals) are used for pressure measurements when the process medium should not come into contact with the pressurized parts of the measuring instrument.

The Pressure diaphragm has two main tasks: to separate the measuring instrument from the process medium; to convey the pressure to the measuring instrument.

The process side of the diaphragm is separated by a flexible diaphragm. The internal space between the diaphragm and the pressure measuring instrument is completely filled with the system fill fluid.

The pressure is transmitted from the measured medium to the filling liquid through the elastic diaphragm, then from the filling liquid to the measuring element, and finally to the pressure measuring instrument, such as a pressure gauge or a pressure gauge transmitter.

Typically, diaphragm seals are mounted on existing fittings or flanges. Fittings consist of T-pieces that are integrated into pipes or welded to pipes, process reactors or tanks. The advantage of this diaphragm seal is: The “contact surface” between the pressure medium and the diaphragm becomes relatively large. This ensures accurate pressure measurement, especially for extremely low pressure conditions (<60 kPa).

The diaphragm seal can be easily removed, e.g. for cleaning or calibration purposes, which is another advantage.

In addition to measuring pressure, pressure transmitters can also be used for many purposes. For example, using differential pressure transmitters to measure flow and using liquid gravity to measure liquid levels. Diaphragm level transmitter is a commonly used pressure level transmitter.

Working principle of diaphragm level transmitter

The working principle of the static pressure level transmitter is: the static pressure of a certain point in the liquid is proportional to the distance from the point to the liquid surface, that is: P=ρgh. Among them: P-pressure (pressure) of the measured point, ρ-medium density, g-gravitational acceleration, h-height from the measured point to the liquid surface. For the determined measured medium ρ, g is a constant, so the change of the position from the measured point to the liquid surface is only related to the measured P pressure (pressure).

When measuring liquid levels in open containers, a pressure transmitter is all that is needed.
When measuring the liquid level of a closed pressure vessel, two pressure or one differential pressure transmitter can be considered. That is, one set for the lower limit of measurement and one set for the upper limit of measurement. Their output signals can be subtracted to measure the liquid level. At this time, a differential pressure transmitter is generally used. It can also be used to measure the density of the medium when the liquid level and pressure in the container remain unchanged.

For airtight containers, since the interior is isolated from the atmosphere. When a process fluid fills or empties a tank, the pressure inside the tank may change from positive to vacuum. This change in tank pressure directly affects the measured liquid level unless compensated for. Connecting the low side tubing from the differential pressure transmitter to the top of the tank will do this. Therefore, when measuring the liquid level of a closed tank, a differential pressure transmitter must be used.

There are many types of pressure transmitters. Here we introduce 4 common types:

  1. Gauge pressure transmitter:
    The gauge pressure transmitter is a pressure transmitter with the local atmospheric pressure as the reference zero point.
  2. Pressure transmitter:
    The pressure transmitter is a pressure transmitter with vacuum as the reference zero point. During use, the reference zero point of the sensor can be automatically adjusted without correction as the location and region change. The appearance is the same as the gauge pressure transmitter.
  3. Differential pressure transmitter:
    The differential pressure transmitter is a pressure transmitter that measures the pressure difference between two pressure chambers. The differential pressure transmitter has two pressure chambers of “+” and “-. Undertake two pressures as comparison values respectively, and usually use the end with higher pressure as the “+” pressure chamber.
  4. Input/insert type liquid level transmitter:
    Liquid level transmitters are divided into two types: input type and plug-in type. The two forms are the same, and both convert the pressure to the liquid depth. When the water depth is 1m, the pressure on the transmitter is 10KPa,

More Featured Industrial Pressure Transmitters

Sino-Inst is the manufacturer of Diaphragm Pressure Transmitters.

There are many types of pressure sensors, such as resistance strain gauge pressure sensors, semiconductor strain gauge pressure sensors, Silicon piezoresistive pressure sensors, inductive pressure sensors, capacitive pressure sensors, resonant pressure sensors and capacitive sensors.

SI-3151TLT Diaphragm Pressure Transmitter-Flange Type is a capacitive pressure detection element. The sensor converts the pressure signal into 4-20mA or other standard signals through a high-performance electronic amplifier and outputs them to secondary meters such as digital displays, regulators, and recorders or DCS systems.

SI-3151TLT Diaphragm Pressure Transmitter-Flange Type is temperature compensated, exquisite all stainless steel hermetic welding and perfect assembly process. The product has the characteristics of high precision, anti-interference, strong overload and impact capability, moisture resistance and long-term stability. A variety of pressure interfaces and electrical interfaces are available for customers to choose, to meet the pressure measurement of various viscous media (mud, coal slurry, paint, crude oil).

The combination of the transmitter and the intelligent amplifying board can constitute an intelligent pressure transmitter. It can communicate with each other through a hand-operated device conforming to the HART protocol for setting and monitoring.

If you need to purchase a SI-3151TLT Diaphragm Pressure Transmitter-Flange Type, or have any technical questions about Diaphragm Pressure Transmitter, please feel free to contact our engineers.

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