Lehry Brothers Exim Pvt. Ltd.

Mechanical Pressure Measurement
Dial indicating pressure gauges for gauge, absolute and differential pressure with bourdon tube, diaphragm, capsule or bellows pressure elements, scale ranges from 0 … 2.5 mbar to 0 … 4000 bar. Accuracies to 0.15 equipped with mechanical, electric and electronic accessories, combinable with various chemical seals.

Diaphragm, In-Line And Capsule-Type Seals
Used for the adaptation of pressure gauges, pressure transducers, pressure transmitters, etc., to extremely difficult measuring operations. It is suitable for extreme temperatures, aggressive, corrosive, heterogonous and toxic over a range of -900C to +4000C and pressures from 10 mbar to 1600 bar.

Electronic Pressure Measurement
Pressure transducers, pressure switches and pressure transmitters for gauge, absolute and differential pressure with peizo resistive, magnetic field dependent and inductive sensors as well as thin film sensors. The measuring ranges from 0 … 0.6 mbar to 0 ... 7000 bar. Standardized current or voltage output signals. Available with digital and analog display and recording equipment as well as pressure calibration systems.

Mechanical Temperature Measurement
Dial indicating thermometers working on bimetal or gas expansion principle with scale ranges from -200⁰C to + 700⁰C. We produce bimetal thermometers, gas-in-metal expansion thermometers, to some extent with electric alarm contacts and transmitters as well as pressure calibration systems.

Electronic Temperature Measurement
Instruments for electronic temperature measurement such as thermocouples, resistance thermometers, analog and digital temperature transmitters, indicating instruments, controllers and calibrators for temperature ranges from -200⁰C to + 1600⁰C.

Mechanical Pressure Gauges
Indicating pressure gauges with elastic measuring element are used very extensively to measure pressures in technical applications because they are robust and easy to handle. There gauges incorporate measuring elements which deform elastically under the influence of pressure. Mechanical pressure gauges are produced with bourdon tube, diaphragm and spring elements and are accordingly different. The measuring elements are made of copper alloys, alloyed steels or produced in special materials for specific measuring applications. Pressures are only measurable in conjunction with a reference pressure. The atmospheric pressure alone serves as reference pressure and the pressure gauge shows how much the measured pressure is higher or lower in relation to the given atmospheric pressure (i.e. an overpressure measuring instrument). The pressure is shown in standard measuring ranges over 270 angle degrees on the dial. Liquid-filled pressure gauges offer optimal protection against destruction by high dynamic pressure loads or vibrations as a result of their cushioning. Switching operations can be carried out when combined alarm contacts and output signals (for example 4 ... 20 mA) can be used for industrial process automation in combination with transmitters.

Pressure Gauges With Bourdon Tube
Bourdon tubes are circular-shaped tubes with an oval cross-section. The pressure of the media acts on the inside of this tube which results in the oval cross section becomes almost round. Because of the curvature of the tube ring tension occurs which bends the bourdon tube. The end of the tube, which is not fixed moves, this movement being a measurement for the pressure. The bourdon tubes bent at an angle of approx. 2500 are used for pressures up to approx. 60 bar. Used for higher pressures are bourdon tubes with a number of superimposed coils of the same diameter (i.e. helical coils) or helical shaped coils (i.e. helical springs) at one level. Bourdon tubes are protected against overload to a limited extent. For particularly difficult measuring operations the pressure gauge can be provided upstream with a chemical seal as separation or protection system. The pressure ranges between 0 ... 0.6 and 0 ... 4000 bar with a reading accuracy (or accuracy class) from 0.1 to 4.0%

Pressure Gauges With Diaphragm Elements
Diaphragm elements are circular-shaped, convoluted membranes. They are either clamped around the" rim between two flanges or welded and subject to the pressure of the media acting on one side. The deflection caused in this way is used as a measurement for the pressure and is indicated by a pointer. These diaphragm elements have a relatively high activating force and because of the annular clamping of the element they are insensitive to vibration. The diaphragm element can be subject to higher overload through load take-up points (by bringing the diaphragm element up against the upper flange). Moreover, the measuring instruments are protected against extremely corrosive media by coating with special material or covering with foil. Wide connection ports, open connection flanges and purging plugs can be integrated for measuring highly viscous, impure or crystallizing media. Pressure ranges are between 0 ... 16 mbar and 0 ... 40 bar in accuracy class 0.6 to 2.5.

Pressure Gauges With Capsule Elements
Pressure gauges with capsule elements are more especially suitable for gaseous media and relatively low pressures. The capsule element comprises two circular-shaped, convoluted membranes sealed tight around their circumference. The pressure acts within this capsule and the generated stroke movement is shown by a pointer as measurement of pressure. Overload protection is possible within certain limits. The activating force is increased if a number of capsule elements are connected mechanically in series (a so-called capsule element "package"). Pressure ranges are between 0 ... 2.5 mbar and 0 ... 0.6 bar in the accuracy class 0.1 to 2.5.

Absolute Pressure Gauges
These instruments are used where pressures is measured independently of the natural fluctuations in atmospheric pressure. The pressure of the medium is to be measured compared against a reference pressure, which, at the same time, is absolute zero. For this purpose an absolute vacuum is given as reference pressure in a reference chamber on the side of the measuring element not subject to pressure. Measuring element movement transmission and pressure indication follow in the same way as with the already described overpressure gauges. The pressure ranges are between 0 ... 16 mbar and 0 ... 25 bar in the accuracy class 0.6 to 2.5.

Differential Pressure Gauges
The difference between two pressures is determined directly and shown on the differential pressure gauge. A differential pressure reading is only given when one of the pressures is either higher or lower. Low differential pressures can be measured directly in the case of high static pressures. Very high overload capability is achieved with diaphragm elements. The permissible static pressure and the overload capability on the positive and negative side must be observed. Transmission of the measuring element movement and pressure indication is the same as with the already described Over pressured gauges in the majority of cases. The pressure ranges between 0 ... 16 mbar and 0 ... 25 bar in the accuracy class 0.6 to 2.5.

Areas of application

• Filter technology (monitoring filter pollution)


• Filling level measurement (in enclosed containers)


• Flow measurement (pressure drop)