SWAS components

Mechatest is well known for it’s excellent quality steam and water sampling and analysis solutions built as per ASME PTC 19.11 and VGB S-006.

The Steam and Water Analysis Systems (SWAS) are designed with worlds best-in-class instrumentation parts to keep the reability of your water steam analysis safe at all times and to protect your power plant from corrosion and scaling. 

As a result, you save maintenance costs, minimize downtime and prolong the operational life for your plant. 

Samples must be taken from locations that are representative of the steam or water source, treatment plant, storage facilities, distribution network, points at which water is delivered to the consumer, and points of use. In selecting sampling points, each locality should be considered individually; however, the following general criteria are usually applicable:

Sampling points should be selected such that the samples taken are representative of the different sources from which water is obtained by the public or enters the system. 
These points should include those that yield samples representative of the conditions at the most unfavourable sources or places in the supply system, particularly points of possible contamination such as unprotected sources, loops, reservoirs, low-pressure zones, ends of the system, etc.
Sampling points should be uniformly distributed throughout a piped distribution system, taking population distribution into account; the number of sampling points should be proportional to the number of links or branches.
The points chosen should generally yield samples that are representative of the system as a whole and of its main components.
Sampling points should be located in such a way that water can be sampled from reserve tanks and reservoirs, etc.
In systems with more than one water source, the locations of the sampling points should take account of the number of inhabitants served by each source.
There should be at least one sampling point directly after the clean-water outlet from each treatment plant.

• Single Helical Tube Sample Cooler
• Compact, high efficiency sample coolers for cooling high temperature/high pressure liquid or gas samples
• Temperature ratings to 593°C at 345 barg (1100°F at 5000 psig)
• Models available for ultra-supercritical power plants with temperature ratings to 621°C at 356 barg (1150°F at 5175 psig)
• Exotic materials such as titanium, Inconel® and Hastelloy® on the tube side, and Monel®, cupronickel, and stainless steel on the shell side are available
• Highest efficiency sample cooler commercially available
• Various configurations available to meet EPRI/ASTM/ASME sampling guidelines
• Many models are available with ASME section VIII code stamp, CE or CRN registrations
• No dead spots or crevices 
• Sample flow rates up to 5.7 liters per minute (1.5 gallons per minute GPM); for higher flow rates see

• High Pressure Sample Flow Control Valve
• The VREL® is an adjustable sample pressure reducerfor sample pressures above 34.5 barg (500 psig) according to the Annual Book of ASTM Standards, ASTM Designation D3370. A precisely machined tapered rod assembly moves inside precision holes within the barrel of the VREL®. Pressure drop is a function of the length of the rods inserted into the barrel.

• Shuts down high temperature sample in less than 5 seconds.
• Need to reset by push button after sample is cooling down
• Protect operators, analyzers and sampling components from high temperature liquids with a Sentry Thermal Shutoff Valve. The sensor/actuator is directly exposed to the sample, providing quick reaction time. Economical and highly reliable replacement for solenoid shutoff valve and temperature controller.
• Suitable for system pressures up to 4400 psi (303 bar)
• Totally mechanical design requires no electricity, air, or hydraulics
• Optional dry contact for remote indication
• Standard trip temperature is 120ºF (49ºC) with other temperatures available
• 316 Stainless Steel construction

• Thermal Shutoff Valve (automatic)
• ThermOmegaTech
• Protects expensive and delicate sample analyzers
• Automatically resets when sample cools
• No outside power required
• Superior value vs. more expensive electric valves

Design Features

• Self-operating thermal actuator controls flow based on fluid temperature
• Operating temperatures unaffected by variable inlet pressures
• Wide choice of setpoints available
• Ram-type plug provides tight shutoff
• Corrosion resistant: all stainless steel construction

Typical Applications

• Excessively hot samples can cause damage to expensive and sensitive hardware and electronics. For process analyzers and similar instrumentation, it is important to assure that the process samples fluids are always below the maximum allowable temperature for such instruments. Sample coolers are commonly used to reduce sample temperatures to the acceptable limits. In the event of a loss of cooling fluid to the sample cooler, or if the desired sample temperature is exceeded for any reason, the HST valve will close to prevent equipment damage. HST valves are covered with our standard 36 month prorated warranty.

• Minimize "dead volume" assuring representative samples
• Three models* (RC-100, RC-200 and RC-400) meet your specific requirements, withstanding the demands of power plants
• Column(s) provide optimum fluid velocity with increased resin efficiency
• Color-changing resin gives quick visual indication of resin depletion level
• Twist-off cap for easy resin refill with available pre-sized Sentry resin refill packets 
• No PVC; wetted materials will not leach chlorides or plasticizers

• Magnetic Trap is effective in removing magnetite and other iron particles from samples. It is easy and intuitive to clean and service.
• The magnet inserts into the "dry well" and does not contact the sample fluid. Magnetite sticks on the wetted side of the drywell. To clean the trap simply divert the sample outlet to drain and remove the magcore from the drywell to flush the magnetite and debris from the trap.
• The cleaning process requires no disassembly of the trap or exposure of the sample to atmosphere. This is especially beneficial when it is used to remove iron oxides and other magnetic material from a sample that feeds Dissolved Oxygen analysers or other sensitive instruments.

Technical Details:

• Rating: 13.8 bar @ 24°C
• Max. Temperature: 65°C
• Dead Volume: 30 ml

• Isokinetic Sampling Nozzles (Probes)

• Sampling gases and liquids for on-line and grab sample chemical analysis can be a major source of errors.  Up to several orders of magnitude concentration changes of dissolved and suspended impurities have been observed when sample withdrawal, cooling, or transport are not properly performed.  Multi-port Steam Sampling Nozzles (Probes) are rarely used because of their complexity, cost, non-isokinetic characteristics, and problems with use in large pipes and they are no longer a part of the ASTM D1066 standard. 

   

  A more appropriate and functional design was developed and the design and performance of these nozzles was verified in the Electric Power Research Institute (EPRI) research project RP2712-8.  This design was then included in ASTM D1066, "Standard Practice for Sampling Steam".  Additional information about the need for isokinetic sampling and the proper design and operation of a sampling system can be found in a technical article entiled "Sampling Savvy"

• ASME PTC 19.11 The specification requires a "isokinetic sample nozzle" for representative sampling of the specific two-phase saturated steam flow via sample ports drilled in the side of the nozzle facing the steam flow.
• Recommended ONLY for saturated steam in steam boiler and power plants, for superheated steam (only if particulates are measured), isokinetic sampling is normally not required for water samples.
  Click here and see our standard sample probes for non-isokinetic sampling.
  
• These nozzles meet also the requirements of ASTM Standards D1066 and D3370.
• The nozzles extract a representative isokinetic sample from a flow region removed from the pipe surface and at the average flow velocity of the sample fluid.      
• This arrangement results in the withdrawal of the sample with representative concentrations of dissolved, suspended, and volatile constituents. Other applications include oil in water, water in oil, propant in oil, and sand in oil.  
• An appropriate nozzle (probe) is designed for the desired sample flow and typical conditions of the sample fluid.  When the flow velocity through the pipe changes, sample flow should be adjusted to maintain isokinetic sampling.
• Each Nozzle (probe) is designed with considerations of vortex shedding, resonance, vibration, erosion, and strength of the attachment to the pipe.