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Summary of Contents for MKS HPS 145 Vacuum Sentry Series
- Page 1 Products Series 145 Vacuum Sentry Safety Valve Operation and Maintenance Manual 651 Lowell Street Methuen, MA 01844 Main Telephone: (800) 227-8766 p/n 100010033 www.mksinst.com Rev. A2 Vacuum Sentry Safety Valve...
- Page 2 AUTO-SOFT are registered trademarks of HPS , a division of MKS Instruments, Inc. SensaVac and Baratron are registered trademarks of MKS Instruments, Inc. Elgiloy is a registered trademark of Elgiloy Co. OFHCis a registered trademark of Amax, Inc. VCR is a registered trademark of Cajon Company.
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Page 3: Table Of Contents
Table of contents Table of contents ............... 3 Package Contents ..............1 Symbols Used in this Manual ............ 1 General Description of Vacuum Sentry ............. Operating Principles Vacuum Sentry ..............Vacuum Sentry Operation Sequence ..........4 Normal Operation - Open position................4 Power Interruption ...................... -
Page 5: Package Contents
Package Contents Before unpacking your Series 145 Vacuum Sentry , check all surfaces of the packing material for shipping damage. Please be sure that your Series 145 Vacuum Sentry package contains these items: 1 Series 145 Vacuum Sentry 1 Series 145 Vacuum Sentry Manual Inspect the Series 145 for visible evidence of damage. -
Page 6: General Description Of Vacuum Sentry
General Description of Vacuum Sentry Products Series 145 Vacuum Sentry is a safety valve, which protects a vacuum system in the event of power failure by isolating the vacuum system and venting the mechanical pump. This avoids oil back up and allows the motor to restart the pump more easily. Vacuum Sentry is offered with the ISO-KF flange sizes and solenoid voltages / frequencies most commonly found on mechanical pumps. -
Page 7: Table Of Contents
Operating Principles Vacuum Sentry Vacuum Sentry ’s solenoid valve is connected in parallel with the mechanical pump’s electrical supply either at its source or at the pump’s switch. See figure 1. When the electrical power is on, the solenoid valve is closed, allowing the pump to keep Vacuum Sentry ’s body and the vacuum system evacuated. -
Page 8: Normal Operation - Open Position
Vacuum Sentry Operation Sequence The mechanical pump is connected to the port on the right side and the vacuum system to the bottom port. Normal Operation - Open position. Power is on to mechanical pump and Vacuum Sentry . The mechanical pump, inlet side of the Vacuum Sentry , and the Vacuum Sentry... -
Page 9: Valve Closed - Mechanical Pump Vented
Valve closed - Mechanical pump vented The piston is fully down and Vacuum Sentry is fully closed. The higher pressure above the piston forces it against the valve seat, where the Viton O-ring makes a vacuum tight seal. Air from the higher pressure area above the piston continues through the small orifice in the top of the piston into the inside of the piston, and through a second small orifice in its side into the mechanical pump’s inlet port. -
Page 10: Specifications
Specifications Nominal body ID 2 inches (50mm) Leak rate - body < 1 x 10 T-l/s - seal < 1 x 10 T-l/s Closing time 30 ms Closing burst 1 x 10 Power 7 Watts @ 115 VAC Materials - body & flanges extruded aluminum A1 6061-T6 - piston machined aluminum A1 2024... -
Page 11: Installation
Installation Electrical The solenoid coil leads should be connected in parallels to the rotary vane pump electrical source, preferably at the pump switch. Be sure that the solenoid voltage and frequency are compatible with those of the pump motor. In the case of three phase electrical power, the solenoid may be connected to one leg and ground. -
Page 12: Service
Service Vacuum components must be kept free of both particulate contamination and all foreign materials which have a significant vapor pressure. Before repairing a vacuum valve, prepare a clean dust-free work are and use clean, degreased tools devoted to precision assembly. Periodically, the Vacuum Sentry should be tested for proper operation. -
Page 13: Repair Of Subassemblies
Repair of Subassemblies Piston / Diaphragm Subassembly Remove diaphragm (11) from piston by unscrewing sleeve (3) from the piston using a spanner wrench, or two 1/8” drill bits, in the 1/8 holes provided in the sleeve. Inspect orifices (19) and (20) and clean if necessary. Be careful not to enlarge the orifices, because performance may suffer. -
Page 14: Bonnet Subassembly
Prepare the new seal by smearing a very light but continuous coat of a vacuum compatible grease on the O-ring. We recommend DuPont KRYTOX GPL 206, which is a high quality fluorinated grease offering low vapor pressure, excellent temperature stability and is chemically inert. - Page 15 With the bottom flange as shown in figure 3, slide O-ring (15) over the boss. Place the return spring (13) inside the bottom flange, as shown in figure 3. Place the body subassembly from step 1 above onto the bottom flange. Align the bolt holes and insert six 10-32 x 5/8 (16) socket cap screws.
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Page 16: Troubleshooting
Troubleshooting This section is a guide for solving problems that may occur with the HPS Vacuum Sentry Valve. Listed below are symptoms with possible causes and suggestions for help. Valve Cannot Be Pumped Down to High Vacuum Valve leaks from external atmosphere into vacuum system. First check that the solenoid has proper electrical power applied to the coil. -
Page 17: Valve Leaks In Closed Position
Valve Leaks in Closed Position Check for proper installation. The valve has been designed to vent the roughing pump upon closure. If the valve has inadvertently been installed backwards it would isolate the pump and vent the system. Reinstall the valve correctly with the flow arrow on the body label pointing toward the mechanical vacuum pump. -
Page 18: Closing Causes Large Burst Of Air Into System
Foreline between the mechanical pump and Vacuum Sentry has a major leak preventing the evacuation of the chamber over the piston (4). Isolate and correct the leak. Excess friction between bushing (2) and guide pin (1). Clean and repair bushing as described above. Nosepiece O-ring is stuck to valve seat due to excess heat, contamination or the improper installation of a dry (ungreased) O-ring. -
Page 19: Factory Repair
Before shipping, observe the following steps: Contact MKS and obtain a Returned Material Report (RMR) number. Use this number on all packing slips, boxes, and asked to answer these questions:... -
Page 20: Accessories / Part Replacement
Accessories / Part Replacement Item Quantity Description Part Number 100003946 Bearing, .19”ID X .25”L 100003897 Sleeve 100003862 Piston NW 40 and NW 50 100003861 Piston NW 25 100005110 O-ring, 2-142, Viton 100003879 .01 oz. Grease, vacuum, KRYTOX 100003907 Body 100003868 Flange, bottom, NW 25 100003909 Flange, bottom, NW 40... -
Page 21: Product Warranty
III. This warranty gives PURCHASER specific legal rights, and PURCHASER may also have other rights which vary from state to state. IV. For HPS products sold outside of the U.S., contact your MKS representative for warranty information and service. Warranty Performance To obtain warranty satisfaction, contact the following: MKS Instruments, Inc., at phone number (800) 227-8766. -
Page 22: Notes
Notes Vacuum SentryTM safety Valve...
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