Botlek Studiegroep Badotherm. Solving measurements issues with Diaphragm seals 3 Case Studies

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Alexander Anderson
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1 Botlek Studiegroep Badotherm Solving measurements issues with Diaphragm seals 3 Case Studies Prepared: 10/04/2015

2 Badotherm Company Summary Badotherm introduction Family owned company Founded by P.B. Bastiaan in 1957, Dordrecht, the Netherlands Manufacturer of diaphragm seals with 6 diaphragm seal facilities around the world to support our global customers Approx. 225 employees worldwide Specialist for developing measurement solutions with diaphragm seals for challenging measurements, e.g. Low gauge pressure measurements High temperature diaphragm seals (HTDS) for up to 600 C Basecal sizing software High variety of filling fluids Gold coating Full welded construction Temperature compensator See also: 10/04/2015 2

3 Introduction Diaphragm Seals A diaphragm seal is used to separate the pressure instrument from the process medium. It protects the sensitive measuring element (e.g. diaphragm of the transmitter or a bourdon tube), with a more robust element. Diaphragm seals are being used when a process is: Too hot Too aggressive / corrosive Too viscous Requiring sanitary connections Creating H+ ions (gold coating) Clogging when cooling down For any of the above reasons, the instrument can not be connected directly to the process. Furthermore, with seals Cleaning is easier (avoiding contamination between batches) Prevention of wet legs 10/04/2015 3

4 Operating principle of diaphragm seals Based on Pascal s principle, i.e. a pressure exerted on a fluid is transmitted undiminished through that fluid in every direction Measuring instrument Transmission fluid Flexible diaphragm Process Pressure 10/04/2015 4

5 When are Diaphragm Seals applied? Diaphragm seals are applied for measuring Absolute and Relative pressure Process pressure Level P = (H*s.g.* 9.81): open tank Pressure Differential Level dp = (H1*s.g.1* 9.81) + (H2*s.g.2* 9.81): closed tank H1 + s.g.1 = Process; H2 + s.g.2 = Filling Fluid Flow dp= m³/h Filter clogging rate 10/04/2015 5

6 What causes a Diaphragm Seal not to work properly The diaphragm displacement is incompatible with the required displacement volume of the instrument s element The diaphragm is too small or too stiff to allow for thermal expansion of the fill fluid, leading to zero shifts and incorrect pressure reading Process or ambient temperatures exceed the acceptable service range to the fill fluid In differential pressure applications if a system has grossly unbalanced volumes on either side of the instrument this may lead to unacceptable zero shifting due to thermal expansion or contraction The differential pressure is too low so reading may not be possible due to the amount of force required to drive both the diaphragm and the measuring element Filling fluid inertia (static head pressure) is greater than the force required to move the measuring element Length and internal diameter of the capillary in combination with fill fluid viscosity creates resistance, driving system response to unacceptable levels For vacuum applications there is a risk for a lack of response and / or nonlinear reading in the lower part of the instrument span Process temperature can influence the ambient temperature close to the process, if the instrument is positioned too closely to the process. This may lead to unacceptable error readings 6

7 Avoiding these problems (1) - Temperature effects Changes in either ambient or process temperature can effect the operation of a diaphragm seal system. Any likely temperature changes should be noted during specification, so that safeguards can be built in. Special attention is to be drawn to the so called mounting effect, this is the variation of the pressure represented by the fill fluid column between the HP and the LP taps, due to the variation of the density of the fill fluid as a result of ambient temperature deviation. Please note that the pressure P1 calculated on the transmitter cell, should not be lower than the specifications of the used transmitter. 7

8 Avoiding these problems (2) - Vacuum applications Care should be taken when specifying a seal system for measuring under vacuum or high vacuum. While the seals perform normally for most standard vacuum applications, as the pressure moves closer to a full vacuum acceptable accuracy becomes more difficult to achieve. This is due to the fact that most filling fluids contain microscopic amounts of air or trapped gases, which tend to expand significantly as a pressure of absolute zero is approached. This expansion undermines one of the most important component factors of a seal system, that of absolutely constant filling fluid volume at any pressure. In order to overcome this potential problem the fully welded construction must be expanded to include the measuring element(cell) itself to avoid leakage, together with a special absolute gas free filling oil and vacuum filling procedure an estimated 5 year lifecycle can be achieved. 8

9 Avoiding these problems (3) - Limitations Process connection versus process pressure Both flanged and threaded process connections have standard restrictions in withstanding pressure (ASME B16.5, ANSI B1.20.1, EN1092-1) The construction of the Diaphragm Seal however can also be a restrictive factor and is specified on the data sheets as the Maximum Working Pressure (MWP) of that Diaphragm Seal. Minimum pressure range A pressure indicator (PI) is a determining part of the usability with a Diaphragm Seal, the PI has its own restrictions in pressure and temperature and volume. The minimum pressure range measurable with each Diaphragm Seal is stated on the data sheets. Pressure transmitters (GP), absolute pressure transmitters (AP) and differential pressure transmitters (dp) are the determining parts, the minimum spans specified on the Badotherm datasheets are spans which still give a reliable measurement performance. A lower span than mentioned is possible, but consult our engineering department in case of these applications. The ideal tool for solving these problems: BaseCal, see further 9

10 Case Study 1- Selection of filling fluid BSO-48 (1) Level measurement with following specifications: dp level application Level range: 300 cm. Density process fluid: 1,02 g/cm³ Process Pressure: 30 mbara Process Temperature: mbara Ambient temperature: -20/+37 C. 10/04/

11 Case Study 1- Selection of filling fluid BSO-48 (2) Where is the challenge? Low absolute pressure in combination with high temperature and severe ambient conditions. Colleague A: Process Temperature: mbara NOT OK (max. 270 C) Ambient temperature: -20/+37 C. OK Colleague B: Process Temperature: mbara OK(?) Ambient temperature: -20/+37 C. NOT OK (min. +10 C) Colleague C: Process Temperature: mbara OK Ambient temperature: -20/+37 C. NOT OK (min +10 C) Badotherm BSO-48 Process Temperature: mbara OK Ambient temperature: -20/+37 C. OK 10/04/

12 Case Study 1- Selection of filling fluid BSO-48 (3) High temperature fill fluid Unique Badotherm developed blend -20/+420 C temperature Excellent performance for high vacuum / temperature applications Badotherm has over 40 specially engineered BSO s available. The process medium is the determining element in choosing a filling fluid: Maximum/minimum temperature Minimum pressure High chlorine or oxygen contents Effects of anti-foaming agents Sanitary requirements such as FDA Response time Viscosity Density 10/04/

13 10/04/ Case Study 1- Selection of filling fluid BSO-48 (4)

14 Case Study 2- Selection of Temperature Compensator (1) The Temperature Compensator is used to lower the response time in combination with long capillaries and high or low temperatures. It uses a specially designed secondary diaphragm and two different fill fluids to meet high temperature specifications, and maintain acceptable response times. 10/04/2015

15 10/04/ Case Study 2- Selection of Temperature Compensator (2)

The tool calculates the total installed performance of the diaphragm seal application, including the transmitter.

16 Case Study 3 Using BaseCal BaseCal is the web-based performance calculation tool for diaphragm seal applications, powered by Badotherm. The tool is intended for instrumentation engineers or anyone wishing to understand the effect of all variables and conditions of a diaphragm seal application. The tool calculates the total installed performance of the diaphragm seal application, including the transmitter. BaseCal allows you to easily change different variables and conditions, so you can simulate and analyze the effect of these different variables. Get your free account at: 10/04/2015

Badotherm solutions: High temperature diaphragm seals - HTDS The HTDS functions as a traditional Diaphragm Seal construction, with a built-in mechanical cooling construction.

Mounted direct to the process to get immediate feedback and response from the process with actual process conditions. It has far less chance of clogging in this construction.

17 Badotherm solutions: High temperature diaphragm seals - HTDS The HTDS functions as a traditional Diaphragm Seal construction, with a built-in mechanical cooling construction. Measures pressure at process temperature up to 600 C Badotherm patented Advantages opposed to traditional cooling towers. Mounted direct to the process to get immediate feedback and response from the process with actual process conditions. It has far less chance of clogging in this construction. The construction can be heat-traced until the upper flange for control of the process temperature. It is a robust construction, less prone to mechanical stress when properly installed and mounted. There is no heavy equipment or special tooling required to install and commission the HTDS and there are no extra costs for piping department to change the piping construction. 10/04/2015

Badotherm Company Summary Ownership structure Privately owned company by Bastiaan family Founded by P.B. Bastiaan in 1957 Board President & CEO Mr.

Bastiaan Locations Headquarters in Dordrecht, The Netherlands Manufacturing sites in Holland, Romania Sales & Diaphragm Seal Service

Services: Applications engineering Process simulation, verification Custom seal design Manifolds & valves Instrument manifolds

special applications Thermometers & Thermowells Gas-filled and Bi-metal thermometers Thermowells End Users Shell DuPont Akzo Nobel

18 Badotherm Company Summary Ownership structure Privately owned company by Bastiaan family Founded by P.B. Bastiaan in 1957 Board President & CEO Mr. P.B.L. Bastiaan Vice-President & Managing Director Mr. P. Bastiaan Locations Headquarters in Dordrecht, The Netherlands Manufacturing sites in Holland, Romania Sales & Diaphragm Seal Service centers in the UK, India, Dubai, Thailand & USA Products Portfolio Diaphragm seals Styles: Flanged Threaded Sanitary Specialty Seal Services: Applications engineering Process simulation, verification Custom seal design Manifolds & valves Instrument manifolds Instrument valves Pressure Gauges Standard stainless steel process pressure gauges Differential pressure gauges Pressure gauges for special applications Thermometers & Thermowells Gas-filled and Bi-metal thermometers Thermowells End Users Shell DuPont Akzo Nobel DSM Petronas Sabic Huntsman Total Engineering companies Foster Wheeler Fluor Daniel CB&I Lummus Jacobs Petrofac Process Automation Honeywell Emerson ABB Yokogawa Invensys Some Customer references 10/04/

BaseCal 3, calculating the performance of Diaphragm Seals

BaseCal 3, calculating the performance of Diaphragm Seals BASECAL: THE DIAPHRAGM SEAL PERFORMANCE CALCULATION TOOL BaseCal is the web-based performance calculation tool for diaphragm seal applications,