Oil and Gas
Pressure measurement in oil processing
Flange type chemical seal with high soft membrane with pressure and differential pressure transmitter, using the original cap flanges (AppBe_Oe_034)for refineries
In this oil processing plant, pressure and differential pressure transmitters are used at ambient temperatures of -18.4 °F up to +158 °F. The medium (crude oil) can reach a temperature of up to +680 °F.
The problem:In former plants, it has been necessary to install an additional trace heating for the capillary line and the chemical seal to obtain an accurate measurement. Furthermore, the original cap flanges had to be replaced by volume-reduced cap flanges that were produced in one-off production.
Our solution:Compared to the sinus membrane, our high soft membrane with its performance can compensate the additional great oil volume in the cap flange (9 cm3 per side) temperature wise, with the result that no additional error occurs, caused by the ambient temperatures -18.4 °F/+158 °F. This error would have to be viewed more critically at an ambient temperature of +158 °F than +752 °F (medium temperature) at the chemical seal, due to the high oil volume in the cap flange. In combination with our special oil (-40 °F/+752 °F), an operation is made possible without the trace heating, which is usually required. The trace heating can also be left out at a process connection of PN 50, which would also lead to further cost reductions.
Our advantages at a glance:
- No need of trace heating
- No need of volume-reduced cap flanges that are produced in one-off production
- No additional errors
Our instrument in detail:No trace heating necessary: MDM 7510 DN 80
- Up to 10-times improved temperature behaviour (up to tA max +752 °F) Temperature-related additional error (mbar/10 K) in the range of -40 °F up to +752 °F
- We can guarantee these values when pressure gauge and diaphragm seal are completed and filled in our factory.
Pressure measurement in gas industry
Pressure gauges for monitoring of residual pressure in gas bottles (AppBe_Oe_035)for manufacturers of monitoring systems for gas bottles,
for manufacturers of fire-extinguishing systems with gases (e.g. Inergen)
Increased caution is required when gas bottles are in use. Misapplication can lead to accidents. Therefore, pressure gauges have to meet high demands.
The problem:There are two types of gas bottles:
- Gas bottles with liquefied content (e.g. propane, carbon dioxide)
- Gas bottles with highly compressed gaseous content (e.g. nitrogen, oxygen, argon)
Liquefied gases change their state of aggregation upon temperature changes. The steam pressure of the liquefied gas determines the pressure within the bottle. The level is determined by weighing. The residual pressure cannot be indicated by the pressure gauge.
The principle for compressed pressurised gases with pressure regulator* is as follows: half pressure – half full. Depending on the type of bottle, the pressure is 200 or 300 bar.
As the gases can partially be aggressive, the material has to fulfil certain requirements, dependent on the type of gas.
* The pressure regulator has two pressure indications. The first indicates the pressure of the gas bottle when it is opened (inlet pressure). With the second valve and the corresponding second indication, the pressure of the gas is controlled that escapes from the pressure regulator (outlet pressure).
We offer the following solutions:When using oxygen, it has to be ensured that all parts are free of grease and oil and have been adjusted residue-free with dry air, since grease and oxygen are inflammable under pressure.
For non-aggressive gas we use inner parts made of non-ferrous metal, alternatively stainless steel or Monel (upon request with helium leak test).
A gas bottle should not be emptied completely to avoid vacuum when cooling.
In order to control the remaining pressure in the bottle, we apply limit switch contact assemblies. This provides the following advantages:
- Securing the supply
- Avoidance of cleaning costs upon full drain
- Control of the min. and max. pressure at the outlet of the regulator
Our advantages at a glance:
- Materials are selected in accordance to the gas
- Limit switch contact assemblies for the control of residual pressure
- Special connection for versions with ultrapure gas
- Safety case
Our instruments in detail:With limit switch contact assembly:
- Thread connection G ¼ B (¼"BSP), ¼" NPT, M10 x 1
- Special connection for versions with ultrapure gas (VCR male thread or union nut)
- Safety case S3
Bourdon tube pressure gauge: RSCh 63
- With reed contact
- Pressure, with which the gas escapes from the bottle
- Pressure range: -1 / + 3 bar (30" Hg vac. - 60 psi)
- Outlet pressure
Bourdon tube pressure gauge: RChE 50 – 3
- With inductive contact
- Content pressure of the gas bottle
- Pressure range: 0 – 250 bar (0 – 3,000 psi)
- Inlet pressure