Spirax Sarco MST21/MST21H Stainless Steel Balanced Pressure Thermostatic Steam Trap
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Description
The Spirax Sarco MST21 Stainless Steel Pressure Balance Thermostatic Steam Trap is a serviceable, pressure-balanced steam trap designed for relatively small condensate discharges, such as in heat tracing applications. Made of stainless steel for corrosion resistance, the trap is available in the standard capacity model MST21 for tracer lines, and in a special high capacity model MST21H for special applications, with the standard bladder labeled with the letters 'STD', which discharges condensate at approximately 10°C below the saturated steam temperature, and the optional 'STD', which discharges condensate at approximately 10°C below the saturated steam temperature, as well as the 'STD', which discharges condensate at about 10°C below the saturated steam temperature. The standard bladder is labeled with the letters 'STD' and discharges condensate at approximately 10°C below saturated steam temperature; the optional bladder labeled with the letters 'SUB' discharges condensate at approximately 22°C below saturated steam temperature, and the bladder labeled with the letters 'NTS' discharges condensate at approximately 4°C below saturated steam temperature.
Available Models
| Available types | SKU |
|---|---|
| MST21 1/4" BSP STD Polished | 11250660 |
| MST21 1/4" BSP NTS Polished | 11251660 |
| MST21 1/2" BSP STD Polished | 11250860 |
| MST21 1/2" BSP NTS Polished | 11251760 |
| MST21H 1/2" BSP STD Polished | 11251460 |
| MST21H 1/2" BSP NTS Polished | 11251860 |
| MST21H 3/4" BSP STD Polished | 11251960 |
| MST21H 3/4" BSP NTS Polished | 11252160 |
| MST21H 1" BSP STD Polished | 11252260 |
| MST21H 1" BSP NTS Polished | 11252460 |
(an official) standard
The product is fully compliant with the European Pressure Equipment Directive 97/23/EC, test reports are available, please specify when ordering if a certificate is required.
Sizes and pipe connections
- MST21: ¼", 3/8" and ½" Screwed NPT or BSP, EN228-1.
- MST21H: ½" and ¾", 1" Screwed NPT or BSP, EN228-1.
Scope of work
- PMA - Maximum Allowable Pressure: 25 bar g@300°C
- TMA - Maximum Allowable Temperature: 400°C @ 23 bar g
- Minimum permissible temperature: 0°C
- PMO - Maximum working pressure: 21 bar g@270°C
- TMO - Maximum operating temperature: 270°C @ 21 bar g
- Minimum operating temperature: 0°C
- Note: For lower operating temperatures, please consult Spirax Sarco.
- Design maximum cold water test pressure: 38 bar g
material (that sth is made of)
| Item | Part | material (that sth is made of) |
|---|---|---|
| 1 | valve body | Austenitic stainless steel ASTM A743 CF16Fa |
| 2 | bonnets | Stainless Steel 420A UGIMA AISI 420 |
| 3 | fluid sac | stainless steels |
| 4 | sprung | Stainless steel BS 2056 302 S26 |
| 5 | partitions | Stainless steel BS 1449 304 S15 |
| 6 | Filter (0.8mm pore size) | Stainless Steel ASTM A240 316L |
| 7 | gaskets | Stainless steel BS 1449 304S15 |
| Note: The materials shown in parentheses are the corresponding standards. |
Weight (approximate)
| caliber | Weight (kg) |
|---|---|
| ¼" | 0.34 |
| ½" | 0.48 |
| 3/8" | 0.48 |
| ¾" | 0.48 |
| 1" | 0.48 |
engine displacement (volume of air fuel mixture drawn in during one cycle)
Includes cold water discharge and hot water discharge, details not explicitly given.
Security information, installation and maintenance
See the Installation and Maintenance Guide (IM-P125-07) supplied with the product for details.
Installation Instructions
This trap is installed vertically, making sure the liquid bladder is level and the inlet is at the top. If horizontal installation is required, it is best to install a drop line before installing the trap. Install suitable shut-off valves before and after the trap to ensure safety during maintenance or replacement. Remove packaging before installation. Slowly open the shut-off valve until the system is working steadily and check for leaks. Note that the body/bonnet gasket contains a stainless steel support ring, so remove it carefully.
deal with
This product is recyclable and does not cause ecological problems when disposed of properly.
Ordering Instructions
Examples: 1 - Spirax Sarco ½" MST21 pressure balanced steam trap with NPT threaded connections. 'STD' type liquid bladder, discharging condensate at approximately 10°C below open saturated steam temperature.
Order spare parts
Please order spare parts as described in the table above and indicate the trap size and type and bladder type. Example: 1 - Internal part for ¼" MST21 steam trap, type 'STD' bladder, discharges condensate approximately 10°C below saturated steam.
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