WIKA differential pressure gauge

We adhere to the principle of integrity-based and quality first, striving for excellent service, reasonable and fair prices, providing various users with excellent and reasonable technical solutions and high-quality pre-sales and after-sales services, and wholeheartedly serving and cooperating with new and old customers!

The conversion mechanism of the movement inside the WIKA pressure gauge in Germany transmits pressure deformation to the pointer

Pressure gauge refers to an instrument that uses elastic elements as sensitive components to measure and indicate pressures higher than ambient pressure. It is widely used in almost all industrial processes and scientific research fields. It can be seen everywhere in fields such as thermal pipelines, oil and gas transmission, water and gas supply systems, vehicle maintenance and repair shops, etc. Especially in industrial process control and technical measurement processes, due to mechanicalWIKA pressure gaugeThe elastic sensitive element has high mechanical strength and easy production characteristics, making it suitable for mechanical applicationsWIKA pressure gaugeIt is becoming increasingly widely used.

The pressure gauge displays pressure by the elastic deformation of sensitive components (Bourdon tube, bellows, bellows) inside the gauge, which is then transmitted to the pointer by the conversion mechanism of the movement inside the gauge, causing the pointer to rotate.

Overflow hole: In the event of an emergency situation where a Bourdon tube bursts, internal pressure will be released to the outside through the overflow hole to prevent the glass panel from bursting. Note: In order to maintain the normal performance of the overflow hole, a space of at least 10mm should be left behind the table, and the overflow hole cannot be modified or plugged.

Pointer: In addition to standard pointers, other pointers are also optional.

Glass panel: In addition to standard glass, other special materials such as reinforced glass and non reflective glass are also optional.

Performance classification: Ordinary type (standard), Steam ordinary type (M), Heat resistant type (H), Vibration resistant type (V), Steam vibration resistant type (MV), Heat resistant and Vibration resistant type (HV).

Treatment method: Oil/water prohibition treatment is used to remove residual water or oil in the liquid contact area during manufacturing.

Exterior: The color of the shell should be specially specified in addition to the standard color.

Throttle valve (optional): To reduce pulsating pressure, the throttle valve is installed at the pressure inlet.

The instrument must be vertical: a 17mm wrench should be used to tighten it during installation, and the case should not be forcefully twisted; Collision should be avoided during transportation;

The instrument should be used in an environment with a temperature range of -25~55 ℃;

The vibration frequency in the working environment should be less than 25Hz, and the amplitude should not exceed 1mm;

During use, if the ambient temperature is too high and the instrument reading does not return to zero or exceeds the tolerance, the sealing rubber plug on the upper part of the watch case can be cut open to allow the instrument chamber to communicate with the atmosphere;

The range of instrument usage should be between 1/3 and 2/3 of the upper limit;

Isolation devices should be added when measuring corrosive media, media that may crystallize, and media with high viscosity;

Instruments should be regularly calibrated (at least once every three months), and if any faults are found, they should be repaired in a timely manner;

If the instrument is found to be ineffective or damaged due to poor manufacturing quality within six months from the date of leaving the factory under normal storage and use conditions, the company shall be responsible for repairing or replacing it;

Instruments for measuring corrosive media should be specified with the required conditions when ordering.

The selection of pressure gauges should be based on the production requirements of the usage process, and specific analysis should be conducted according to the specific situation. On the premise of meeting the process requirements, comprehensive consideration should be given to the principle of conservation. Generally, the following aspects should be considered:

Selection of Types

The selection of instrument types must meet the requirements of process production. For example, whether remote transmission, automatic recording, or alarm are required; Whether the properties of the measured medium (such as temperature, viscosity, corrosiveness, degree of dirt, flammability and explosiveness) have special requirements for the instrument, and whether the on-site environmental conditions (such as humidity, temperature, magnetic field strength, vibration, etc.) have requirements for the type of instrument. Therefore, selecting the appropriate instrument type according to process requirements is an important prerequisite for ensuring the normal operation and safe production of instruments.

For example, the spring tube of ordinary WIKA pressure gauges is mostly made of copper alloy (alloy steel is used for high pressure), while the spring tube of ammonia WIKA pressure gauges is made of carbon steel (or stainless steel), and copper alloy is not allowed to be used. Because ammonia reacts chemically with copper and can explode, ordinary WIKA pressure gauges cannot be used for ammonia pressure measurement.

The oxygen WIKA pressure gauge can be the same in structure and material as a regular WIKA pressure gauge, except that the oxygen WIKA pressure gauge must be oil free. Because oil entering the oxygen system can easily cause explosions. When calibrating the oxygen WIKA pressure gauge, oil should not be used as the working medium like ordinary WIKA pressure gauges, and the oxygen WIKA pressure gauge should be stored strictly to avoid contact with oil stains. If it is necessary to use the existing WIKA pressure gauge with oil stains to measure oxygen pressure, it must be repeatedly cleaned with carbon tetrachloride before use and carefully inspected until there is no oil stain.

Determination of measurement range

In order to ensure that the elastic element can work reliably within the safe range of elastic deformation, when selecting the range of WIKA pressure gauge, sufficient margin must be left according to the magnitude of the measured pressure and the speed of pressure change. Therefore, the upper limit value of WIKA pressure gauge should be higher than the maximum pressure value that may be possible in process production. According to the "Technical Regulations for Chemical Automation Design", when measuring stable pressure, the maximum working pressure should not exceed 2/3 of the measurement upper limit value; When measuring pulsating pressure, the maximum working pressure should not exceed 1/2 of the measurement upper limit value; When measuring high pressure, the maximum working pressure should not exceed 3/5 of the measurement upper limit. The minimum value of the measured pressure should generally not be less than one-third of the upper limit value of the instrument measurement. Thus ensuring a linear relationship between the output and input of the instrument

After calculating the upper and lower limits of the instrument based on the maximum and minimum values of the measured parameter, these values cannot be directly used as the measurement range of the instrument. When selecting the upper limit value of the instrument scale, we should choose from the standard series specified by the country. The WIKA pressure gauge measurement range standard series in China includes: -0.1-0.06, 0.15; 0-1,1.6,2.5,4,6,10X10 'MPa (where n is a natural integer) Can be positive or negative).

Selection of accuracy level

Based on the maximum absolute error allowed by the production process and the selected instrument range, calculate the maximum allowable reference error of the instrument, and determine the accuracy of the instrument in the national prescribed accuracy level. Generally speaking, the more precise the instrument selected, the more accurate and reliable the measurement results will be. But it cannot be assumed that the higher the accuracy of the selected instrument, the better, because more precise instruments are generally more expensive, and the operation and maintenance are more complicated.

Example selection:

When used to measure special media such as viscosity or acidity or alkalinity, diaphragm WIKA pressure gauges, stainless steel spring tubes, stainless steel movements, stainless steel shells or rubberwood shells should be selected.

According to the different media being measured, there should be specified color codes on the WIKA pressure gauge, and the name of the special medium should be indicated. The oxygen gauge must be marked with the red word "no oil", hydrogen with a dark green underline, ammonia with a yellow underline, and so on.

When installing against a wall, WIKA pressure gauges with edges should be selected; When directly installed on pipelines, WIKA pressure gauges without edges should be selected; When used for direct gas measurement, a WIKA pressure gauge with a safety hole on the back of the case should be selected. For the consideration of pressure measurement location and ease of observation and management, the size of the watch case diameter should be chosen.

There are many types of pressure gauges, including not only general (ordinary) pointer indication type, but also numerical type; There are not only conventional types, but also special types; Not only contact type, but also remote transmission type; There are not only vibration resistant types, but also seismic resistant types; Not only diaphragm type, but also corrosion-resistant type. The WIKA pressure gauge series is complete. It not only has a regular series, but also a digital series; There are not only ordinary media application series, but also special media application series; There are not only switch signal series, but also remote transmission signal series, etc., all of which originate from practical needs and have successively formed a complete series. The specifications and models of WIKA pressure gauges are complete, and the structural type is *. From the nominal diameter perspective, there are various sizes such as Φ 40mm, Φ 50mm, Φ 60mm, Φ 75mm, Φ 100mm, Φ 150mm, Φ 200mm, and Φ 250mm. From the perspective of installation structure types, there are direct installation type, embedded type, and convex type. Among them, embedded type is further divided into radial embedded type and axial embedded type, and convex type is also divided into radial convex type and axial convex type. Direct installation type is divided into radial direct installation type and axial direct installation type. The radial direct installation type is the basic installation type, and generally refers to the radial direct installation type when the installation structure type is not specified. Axial direct installation type considers the stability of its own support and is generally only selected for WIKA pressure gauges with a nominal diameter less than 150mm. The so-called embedded and convex WIKA pressure gauges are commonly referred to as WIKA pressure gauges with edges (mounting rings). Axial embedded type refers to the WIKA pressure gauge with a forward edge, radial embedded type refers to the radial forward edge, and radial convex type (also known as wall mounted type) refers to the radial backward edge. From the perspective of measurement range and range section, the positive pressure measurement range is divided into micro pressure range section, low pressure range section, medium pressure range section, high pressure range section, and ultra-high pressure range section. Each range section is further subdivided into several measurement ranges (instrument range); There are three types of negative pressure (vacuum gauge) in the negative pressure range (vacuum); The WIKA pressure gauge with positive and negative pressure linkage is a cross domain WIKA pressure gauge. Its standard name is pressure vacuum gauge, also known as vacuum WIKA pressure gauge. It can measure not only positive pressure but also negative pressure. The accuracy classification of WIKA pressure gauges is very clear. Common accuracy levels include 4, 2.5, 1.6, 1, 0.4, 0.25, 0.16, 0.1, etc. The accuracy level should generally be marked on its dial, and there are corresponding regulations for its identification, such as "①" indicating that its accuracy level is level 1. For some WIKA pressure gauges with very low accuracy levels, such as those below level 4, there are also some that do not require accurate pressure measurement and only need to indicate the pressure range, such as the WIKA pressure gauge on a fire extinguisher, the accuracy level can be omitted.