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Pressure gauges

The stainless steel pressure gauge is a product of high quality. The stainless steel pressure systems are all provided with seamless drawn tube which reduces the chance of tube rupture. All Pressure gauges have the connection welded into the case and is produced according to the international standard EN837 and the PED. The pressure gauges can be supplied with material certificates according EN10204 3.1, with NACE MR01-75 (ISO-15156) compliance and/ or calibration certificates. Our pressure gauges are also suitable to be supplied in explosive atmospheres and can be supplied with ATEX 114 compliance certification. The most safe stainless steel pressure gauge is the solid front type with baffle wall and blow out protection (BDT20).

Bourdon tube pressure gauge

Diaphragm pressure gauge

Capsule pressure gauge

Pressure gauge accessories

  • Can I create my own dial design?

    Yes. Badotherm offers the possibility to put your own company logo on the dial. A complete dial design can be made as well with all colors and shapes to create the best dial face for the operating situation.

  • What type of pressure gauge principle do I need to choose?

    Pressure gauge principle is depending on the pressure range to be measured. Up to 600 mbar a capsule or diaphragm system is the only possibility. From 600 mbar up to 25 bar diaphragm and bourdon tube principles are possible. Above 25 bar bourdon tube principle gauges is the only possibility.

  • What are the most relevant information to select a pressure gauge?

    In order to make the right selection of a pressure gauge below information are essential:

    -Dial Size
    -Scale Range
    -Measuring System
    -Material Selection
    -Mounting Option
    -Process Connection
    -Case filling
    -Window Material
    -Safety Level
    -Accessories (if any)
    -Certificate & Document requirements

  • What is the material of construction of my pressure gauge?

    It is critical that the materials of the gauge’s pressure system are suitable with the media that its measuring. Typical materials for the measuring system and the connection are:
    -AISI 316 Bourdon tube / diaphragm / capsule / socket
    -Alloy 400 Bourdon tube and socket / diaphragm

  • What’s the difference between a standard and a safety pattern gauge?

    The safety pattern gauge is constructed for the oil & gas industries and are therefore designed to fulfil the highest safety standards. When constructed an additional solid baffle wall is welded between the measuring system and the dial. The window is safety glass and a full blow out back plate is mounted in the back. The standard industrial pressure gauge does not have these features and is executed with a blow out plug and can be supplied with different window materials.

  • When do I need to fill the pressure gauge?

    The filled option for pressure gauges should be selected when the pressure gauge is installed in a vibration situation or a pulsating process pressure is present. These conditions can cause fluttering of the pointer and movement. The reading is not stable, difficult to read and the internal parts are subjected to wear. Another reason for case filling can be done to prevent fogging of the inside of the window. This can occur when the case inside and the ambient temperature are changing rapidly. Filling the gauge with several filling fluids (i.e. glycerin, silicone or halocarbons), reduces the side effect of vibration, thereby extending the life of the gauge and making reading easier.

  • How to choose the scale of a pressure gauge?

    Stainless steel pressure gauges are made to work up to the maximum scale value. However the readability is best between the 25% and 75% of the full scale value. When selecting a pressure gauge it is wise to select the full scale range 2x the normal operating pressure. For example, if an end-user’s process is working at 5 bar, a Pressure Gauge with a range of 0 to 10 bar should be selected. In case design pressures are to be met, then the gauges could be support with an extra ‘overrange protector’ accessory such as the BDT49.

  • My pointer is not at zero. What shall I do? What might happened?

    There might be several reasons causing this problem. Each reason may require different solutions:

    1. Changes in ambient temperatures: this may create an internal pressure within the casing due to changes of ambient temperatures. Check if the fill plug is pierced, or vent the case by means of opening the filling cap would solve the problem.
    2.  Gauge might be in operation for a long period of time and hence out of calibration: you can send the gauge to Badotherm to be checked. The gauge can be checked on functioning and it can be adjusted and calibrated when needed.
    3. The gauge might has fallen or exposed to physical shocks: as a result, the mechanism might be affected and therefore gauge might be damaged and not suitable for use anymore. The gauge needs adjustment and checking before putting it in use.
    4. Gauge might be exposed to overrange or pressure spike: The gauges have a certain limit depending on the scale range and model. Normally gauges are protected up to 130% overrange. However, when this value is exceeded then the gauge cannot held and the tube or welds can be damaged. Therefore the pointer might not be at zero when not pressurized.

Bourdon tube pressure gauges

Pressure gauges are among the most common and most used pressure measurement devices worldwide. The principle of the “Bourdon tube” was developed by Eugène Bourdon in 1849 but its technology is still being used. A bourdon tube pressure gauges consists of a bourdon tube bent into an arc or circle. the cross section of the tube is elliptical. One end of tube is connected to the connection where the pressure need to be measured, the other end is connected to a mechanism steering the pointer.

The working principle of a bourdon tube is that the when the process medium to be measured (gas or fluid) this flows in the tube and the elliptical cross section tends to become circular. This makes the tube to straighten itself with an increase in radius. this causes the free end of the tube to move or displace. This displacement steers the pointer via the mechanism and the pointer moves over the scale. Bourdon tubes are made in 2 different shapes, C-shape and a coil (or pigtail) shape type which has several winded coils of the same diameter (helical coils). The Pigtail is used for measuring high pressures starting above 60 bar and over.

Pressure gauges still are being used a lot in the heavy industries. They are fairly low cost and a simple and proven construction. They are available in a large variety of ranges. However, the instruments remain sensitive to shocks and vibrations. Pressure gauges remain essential in the industry though, because they don’t require any electricity and are easily remote readable and understandable. So in case of power shutdowns and local checks, the processes can still be checked and kept under control. Since pressure gauges are used more selectively, more attention is given to the right selection. In combination with diaphragm seals the durability and lifetime of the pressure gauges can be significantly prolonged ensuring longer uptime, less maintenance cost (less replacements in the field) lower procurement cost (fewer quantities because the no longer break) and increased safety for the operators.

Diaphragm pressure gauges

Badotherm has 2 type of diaphragm pressure gauges

For low pressure measurement, Badotherm type BDT12, it is a mechanical diaphragm construction. The diaphragm element is circular shaped, convoluted membranes that are welded between two flanges around the rim. The process pressure exerts a force on the diaphragm, a metal pushrod (link) fixed to the top of the diaphragm transmits the deflection of the diaphragm to the movement. The movement translates the lateral motion of the push rod into a rotational motion of the pointer.

Differential pressure gauges, Badotherm type BDT13, measures the difference between two pressures. This is down by means of a double diaphragm based on Badotherm diaphragm seal technology, measuring and exerting the pressure of both sides by means of it hydraulic system. These instruments are suitable for the monitoring of filter contamination, for level measurement in closed vessels, for overpressure measurement in clean rooms, for flow measurement of gaseous and liquid media and for the control of pumping plants. Badotherm BDT13 can be supplied in many exotic materials and can be equipped with diaphragm seals as well.

Capsule pressure gauges

Capsule element pressure gauges consist of two circular shaped corrugated membranes welded or soldered together at the outer sides. The pressure acts on the inside of the capsule and the expansion of the capsule creates a deflection of the capsule which is translated by a geared movement to a rotational movement causing the pointer to move over the face of the dial. This method is perfectly suitable to measure very low pressures from 16 up to 600 mbar. Depending on the type of capsule used it is possible to measure negative, compound or positive pressure. Capsule pressure gauges are made according to the EN 837 standard in the sizes 63mm, 100mm, and 160mm. Pressure gauges with capsule elements are suitable for gaseous media with low pressures.

Pressure gauge accessories

Badotherm has a wide range of pressure gauge accessories that can be supplied in combination with the pressure gauges. They can be supplied as loose items, but mostly them come complete assembled, pre-set and tested from the Badotherm factories. A short summary of the accessories are

Mounting brackets (BDT40)
Syphons (BDT42, BDT43, BDT44)
flanged process connections
Overpressure protectors (BDT49)
Adjustable snubbers and pulsation dampeners (BDT45, BDT46)
Swivel gauges adaptors (BDT47)
Extension nipples
Shut of valves and manifolds (BDTV910 or BDTM92x)

and of course, our diaphragm seals and related filling fluids