Emerson Vilter VSG128 Setup guide

HPLD Single Screw
Bare Shaft Compressor
Installation, Operation and Service Manual

i
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
What is covered & how long it is covered: Subject to the other terms of this Warranty Statement, Seller warrants to its
direct purchasers (and to no others) that the Products it manufactures will be free from defects in material and work-
manship under normal use, regular service and maintenance. This warranty only applies when such defect appears
in the Products within 12 months (“m”) from the date such Products are placed in service and when such Products
are returned to and received by Seller within 18m from the date of manufacture by Seller (“12m/18m”), except that
defects in the following Products different than 12m/18m are covered by the number of months indicated below if
returned to Seller within the following number of months (“m Ship”) from shipment by Seller—
What is not covered: This warranty does not extend to any losses or damages due to misuse; corrosion; accident;
abuse; neglect; normal wear and tear; negligence (other than Seller’s); unauthorized alteration; use beyond rated ca-
pacity; acts of God; war or terrorism; unsuitable power sources or environmental conditions; operation with refrigera-
tion or lubricants which are not suitable for use with the Product; improper installation, repair, handling, maintenance
or application; substitution of parts not approved by Seller; or any other cause not the fault of Seller. This warranty is
only applicable to Products properly maintained and used according to Seller’s instructions, the use of genuine Vilter™
replacement parts and recommended oil in all repairs, and when Buyer has demonstrated adherence to a scheduled
maintenance program as detailed in the applicable operating manual. The Buyer must use Vilter approved oil only and
provide oil analysis results to Vilter. To the extent the Buyer has supplied specications, information, representation of
operating conditions or other data to Seller in the selection or design of the Products and the preparation of Seller’s
quotation, and in the event that actual operating conditions or other conditions differ from those represented by
Buyer, any warranties or other provisions contained herein which are affected by such conditions will be null and void.
Seller does not warrant that the Products comply with any particular law or regulation not explicitly provided in the
Product specications, and Buyer is responsible for ensuring that the Products contain all features necessary to safely
perform in Buyer’s and its customers’ plants and operations. If the Products are for a gas compression application,
this warranty does not apply if the Products are operated in conjunction with a gas with an H2S level above 100 PPM.
Product
Compressor Type
Reciprocating
Compressors
VSS / VSM Refrigeration
Compressors
VSG / VSSG Gas
Compressors
New Unit 24m Ship 24m Ship 12m/18m
Compressor
(New Unit Only) 24m Ship 60m Ship 12m/18m
New Bareshaft
Compressor 24m Ship 24m Ship 12m/18m
Remanufactured
Compressor 12m/18m 12m/18m 12m/18m
Any Engineered to Order (ETO) packaged system (including Heat Pumps and
Process Chillers) not described above carry the 12m/18m warranty.
VSS / VSM single screw compressors installed and shipped on New Units carry
an internal Product component warranty of 5 years from shipment date and a
warranty of 15 years from shipment date for compressor bearings only. Does
not include actuator motors and shaft seals.
Vilter™ Genuine OEM Parts, retrot Vission 20/20 panels, retrot PLC panels and
any other supplied equipment not described above carry a 12m warranty from
shipment date.
New Vapor Recovery Units (“VRU Units”) and its Compressors carry the stan-
dard 12m/18m warranty—all other VRU parts carry a 6 m warranty from ship-
ment date.
Standard VILTER™ Warranty Statement

ii HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Third Party Motors & Starters: Motors and starters or Motor & Starter Parts purchased by Seller from a third party
for resale to Buyer or for incorporation into Seller’s Product will carry only the warranty extended by the original
manufacturer (“OEM”). Motor manufacturer warranties cover only the repair or replacement of the motor, and do not
cover removal and installation charges, incidental charges associated with the removal and installation process, loss
of product, or shipping to and from the manufacturer or approved shop. The individual motor manufacturer warranty
terms can be found on the manufacturer’s associated websites.
Other limitations: Seller will not be liable under the above warranty if Buyer is in default of its payment obligations
to Seller under any purchase order or credit agreement. Except with Seller’s written permission given after receipt of
Buyer’s request within 60 days of an event, Seller will not be responsible for costs of dismantling, lost refrigerant, reas-
sembling, repair labor and expenses, travel cost or transporting the Product. Products repaired or replaced under this
warranty will be warranted for the unexpired portion of the warranty applying to the original Products. Buyer agrees
that all instructions and warnings supplied by Seller will be passed on to those persons who use the Products. Products
are to be used in their recommended applications and all warning labels adhered to the Products by Seller must be left
intact. Any technical advice furnished by Seller before or after delivery in regard to the use, application or suitability of
the Products may not be construed as an express warranty unless conrmed by Seller in writing, and Seller assumes
no obligation or liability for the advice given or results obtained—all advice given and accepted at Buyer’s sole risk.
Exclusive Remedy: Within (10) ten days after Buyer’s discovery of any warranty defects within the warranty period,
Buyer will notify Seller of such defect in writing. Seller will, at its option and as Buyer’s exclusive remedy, repair, correct,
or replace F.O.B. point of manufacture, or issue credit or refund the purchase price for, that portion of the Products
found by Seller to be defective. Failure by Buyer to give such written notice within the applicable time period will be
deemed an absolute and unconditional waiver of Buyer’s claim for such defects. Buyer assumes all other responsibility
for any loss, damage, or injury to persons or property arising out of, connected with, or resulting from the use of the
Products, either alone or in combination with other products/components. If so required, Products or parts for which
a warranty claim is made are to be returned transportation prepaid to Seller’s factory. THE FOREGOING CONSTITUTES
THE SOLE AND EXCLUSIVE REMEDY FOR BREACH OF ANY WARRANTY HEREUNDER.
SOLE WARRANTY: THE WARRANTIES ABOVE CONSTITUTE SELLER’S SOLE AND EXCLUSIVE WARRANTIES WITH
RESPECT TO THE PRODUCTS AND ARE IN LIEU OF AND EXCLUDE ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
ARISING BY OPERATION OF LAW OR OTHERWISE, INCLUDING MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE WHETHER OR NOT THE PURPOSE OR USE HAS BEEN DISCLOSED TO SELLER IN SPECIFICATIONS,
DRAWINGS OR OTHERWISE, AND WHETHER OR NOT SELLER’S PRODUCTS ARE SPECIFICALLY DESIGNED AND/OR
MANUFACTURED BY SELLER FOR BUYER’S USE OR PURPOSE.
LIMITATION OF LIABILITY: SELLER SHALL NOT BE LIABLE FOR DAMAGES CAUSED BY DELAY IN PERFORMANCE AND
THE REMEDIES OF BUYER HEREIN ARE EXCLUSIVE. IN NO EVENT, REGARDLESS OF THE FORM OF THE CLAIM OR
CAUSE OF ACTION (WHETHER BASED IN CONTRACT, INFRINGEMENT, NEGLIGENCE, STRICT LIABILITY, OTHER TORT
OR OTHERWISE) SHALL SELLER’S LIABILITY TO BUYER AND/OR ITS CUSTOMERS EXCEED THE PRICE PAID BY BUYER
FOR THE SPECIFIC PRODUCTS OR PORTION OF THE PRODUCTS PROVIDED BY SELLER GIVING RISE TO THE CLAIM OR
CAUSE OF ACTION, AND BUYER SHALL INDEMNIFY AND HOLD HARMLESS SELLER FOR ANY DAMAGES INCURRED
BY SELLER IN EXCESS THEREOF. BUYER AGREES THAT IN NO EVENT SHALL SELLER’S LIABILITY TO BUYER AND/OR ITS
CUSTOMERS EXTEND TO INCLUDE INCIDENTAL, CONSEQUENTIAL OR PUNITIVE DAMAGES. The term “consequential
damages” includes loss of anticipated prots, business interruption, loss of use, revenue, reputation and data, costs in-
curred, including for capital, fuel, power and loss or damage to capital or equipment. Buyer agrees that all instructions
and warnings supplied by Seller will be passed on to those persons who use the Products. Seller’s Products are to be
used in their recommended applications and all warning labels adhered to the Products by Seller are to be left intact.
Standard VILTER™ Warranty Statement

iii
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
!
WARNING
Read and understand
operator´s manuals before
using this machine.
Failure to follow operating
instructions could result in
serious injury.
Important Message
READ CAREFULLY BEFORE INSTALLING AND STARTING YOUR COMPRESSOR.
The following instructions have been prepared to assist in installation, operation and removal of VilterTM HPLD Single
Screw Bare Shaft Compressors. Following these instructions will result in a long life of the compressor with satisfac-
tory operation.
The entire manual should be reviewed before attempting to install, operate, service or repair the compressor.
Only qualified personnel shall operate, install and maintain the equipment.
Qualified personnel shall be accredited by a local regulatory agency, which requires that they are continually scruti-
nized by an organization whose sole mission is to establish, maintain and assure that the highest industry standards
are set and met in a continuous and ongoing basis. The credentials shall address topics ranging from plant safety,
operating concepts and principles and operations through the basics of refrigeration compliance and PSM (Process
Safety Management) requirements.
Follow local workplace occupational safety and health regulations.
A compressor is a positive displacement machine. It is designed to compress gas. The compressor must not
be subjected to liquid carry over. Care must be exercised in properly designing and maintaining the system to
prevent conditions that could lead to liquid carry over. VilterTM Manufacturing is not responsible for the system
or the controls needed to prevent liquid carry over and as such VilterTM Manufacturing cannot warrant equip-
ment damaged by improperly protected or operating systems.
VilterTM HPLD Single Screw Compressor components are thoroughly inspected at the factory. However, dam-
age can occur in shipment. For this reason, the equipment should be thoroughly inspected upon arrival. Any
damage noted should be reported immediately to the Transportation Company. This way, an authorized agent
can examine the unit, determine the extent of damage and take necessary steps to rectify the claim with no
serious or costly delays. At the same time, the local VilterTM representative or the home office should be noti-
fied of any claim made.
All inquires should include the VilterTM sales order number, compressor serial and model number. These can be found
on the compressor name plate on the compressor.
All requests for information, services or parts should be directed to:
Vilter Manufacturing LLC
Customer Service Department
5555 South Packard Ave
Cudahy, WI 53110-8904 USA
Telephone: [phone]; Fax:[phone]
E-mail: [e-mail]; Web: Emerson.com/Vilter
Equipment Identification Numbers:
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________

iv
EC Declaration of Incorporation
We hereby declare that the following machinery is intended to be incorporated into other machinery, and must
not be put into service until the relevant machinery into which it is to be incorporated has been declared in con-
formity with the essential requirements of the Machinery Directive 2006/42/EC.
Machine Description: Industrial Compressor
Make: Vilter
Type: VSM / VSS / VSH / VSSH / VSG & VSSG Single Screw Compressor
Model Size: 97, 113, 127, 128, 145, 160, 180, 204, 222, 243, 152, 182, 202, 301, 361, 401, 501, 601,
701, 291, 341, 451, 601, 751, 901, 791, 891, 1051, 1201, 1301, 1551, 1851, 2101, 2401,
2601, 2801, 3001
Manufactured by: Vilter Manufacturing, LLC.
The following transposed harmonised European Standards have been used:
EN ISO 12100-1:
2010
- Safety of Machinery - General principles for design-Risk assessment and risk reduction.
EN ISO 13857:
2008
- Safety of Machinery - Safety distances to prevent danger zones being reached by the
upper and lower limbs.
EN349: 1993 + A1:
2008
- Safety of Machinery - Minimum gaps to avoid crushing hazards.
EN ISO 13850:
2015
- Safety of Machinery - Emergency stop equipment - Principles for design.
IEC/EN60204-1 (2016) - Safety of Machinery - Electrical equipment of machines - Specication for general
requirements
A technical construction le for this machinery is retained at the following address:
Vilter Manufacturing, LLC.
5555 South Packard Avenue
P.O. Box 8904, Cudahy
Wisconsin 53110-8904
Signed for and on behalf of Vilter Manufacturing, LLC.:
Last update: May 2019
Vilter Manufacturing, LLC.
5555 South Packard Avenue t P.O. Box 8904 t Cudahy, Wisconsin 53110-8904
001-414- 744-0111 t FAX: [phone]

TOC − 1
Table of Contents
Section Title Page Number
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Standard Vilter Warranty Statement ......................................................................................................i
Important Message................................................................................................................................iii
EC Declaration of Incorporation .............................................................................................................iv
Section 1 • General Information
How To Use This Manual.........................................................................................................................1-1
Additional Important Notes ...................................................................................................................1-1
System Unit Identification .....................................................................................................................1-2
Bare Shaft HPLD Compressor Model Designations..................................................................................1-3
Section 2 • Theory of Operation
Introduction ..........................................................................................................................................2-1
Compressor ...........................................................................................................................................2-1
Capacity and Volume Control.................................................................................................................2-2
Description of a Gas System For a Standard Compressor Set...................................................................2-3
Description of an Oil System For a Standard Compressor Set ..................................................................2-3
Critical Application Guidelines ...............................................................................................................2-4
Procedure For System Pressurization......................................................................................................2-5
Alarm and Shutdown Readings ..............................................................................................................2-6
HPLD Package Requirements .................................................................................................................2-7
Section 3 • Installation
Delivery Inspection ................................................................................................................................3-1
Rigging and Lifting of the Compressor ...................................................................................................3-1
Compressor Inspections Prior to Installation ..........................................................................................3-2
Long Term Storage Recommendations...................................................................................................3-2
Long Term Storage Log...............................................................................................................3-3
Notice on Using Non-Vilter Oils..............................................................................................................3-4
Instrumentation Requirements..............................................................................................................3-4
Pressure .....................................................................................................................................3-4
Temperature ..............................................................................................................................3-5
Miscellaneous.............................................................................................................................3-5
Piping ....................................................................................................................................................3-6
Testing System For Leaks........................................................................................................................3-7
Hydrocarbon Systems ................................................................................................................3-7
CO2Systems...............................................................................................................................3-7
Oil for Single Screw Compressors...........................................................................................................3-7
Section 4 • Operation
Notice on Using Non-Vilter Oils..............................................................................................................4-1
Operation ..............................................................................................................................................4-1
Control System ......................................................................................................................................4-1
Starting, Stopping and Restarting the Compressor.....................................................................4-1
Safety Setpoints .........................................................................................................................4-1
HPLD Control with Vission20/20™ Micro-Controller...............................................................................4-2

TOC − 2
Table of Contents
Section Title Page Number
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Section 5 • Maintenance/Service
Maintenance and Service Schedule ........................................................................................................5-1
Recommendations When Servicing........................................................................................................5-2
Preparation of Unit for Servicing ............................................................................................................5-2
Oil Sampling ..........................................................................................................................................5-3
Recommendations .....................................................................................................................5-3
Installation of The Oil Sampler Valve...........................................................................................5-3
Pre-Sampling .............................................................................................................................5-3
Sampling Procedure...................................................................................................................5-4
Oil Sample Analysis Report.........................................................................................................5-6
Compressor Inspection ..........................................................................................................................5-7
Bearing Inspection .....................................................................................................................5-7
Determining Maximum Applied Force For Main Rotor Bearings And Gaterotor Bearings..5-7
Method of Inspection .....................................................................................................5-7
A) Preparation ..................................................................................................5-7
B) Main Rotor Bearing Inspection......................................................................5-7
C) Gaterotor Bearing Inspection .......................................................................5-9
Gaterotor Inspection ..................................................................................................................5-10
A) Gaterotor - Main Housing Shelf Clearance...................................................................5-10
B) Gaterotor Float Measurement.....................................................................................5-11
C) Gaterotor Backlash Inspection ....................................................................................5-12
Important notes.........................................................................................................................5-14
Additional Inspections................................................................................................................5-14
Post Inspection...........................................................................................................................5-14
Gaterotor Removal and Installation........................................................................................................5-15
Removal ....................................................................................................................................5-15
Installation.................................................................................................................................5-19
Gaterotor Blade Removal............................................................................................................5-21
Gaterotor Blade Installation........................................................................................................5-21
Gaterotor Ball Bearing Removal ..................................................................................................5-22
Gaterotor Ball Bearing Installation ..............................................................................................5-22
Gaterotor Roller Bearing Removal...............................................................................................5-22
Gaterotor Roller Bearing Installation...........................................................................................5-22
Compressor Shaft Seal Replacement ......................................................................................................5-24
Shaft Seal Assembly ...................................................................................................................5-24
Handling Seal Face with Care......................................................................................................5-24
Shaft Seal Removal.....................................................................................................................5-25
Prior to Shaft Seal Installation (For all HPLD shaft seal models)....................................................5-26
Shaft Seal Installation ................................................................................................................5-27
Main Rotor Assembly .............................................................................................................................5-28
Torque Specifications.............................................................................................................................5-28
Using A Torque Wrench Correctly...........................................................................................................5-29
Nord-Lock®Washers ..............................................................................................................................5-29
Section 6 • Troubleshooting
Troubleshooting Guide, General Problems and solutions........................................................................6-1
Section 7 • Warranty and Parts
Warranty Claim Processing ....................................................................................................................7-1
Motor Warranty Procedure ....................................................................................................................7-2
On-Site Service Support.........................................................................................................................7-3

TOC − 3
Table of Contents
Section Title Page Number
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Remanufactured HPLD Bare Shaft Single Screw Compressor .................................................................7-3
Explanation of Rebuild Levels......................................................................................................7-3
Section 8 • Spare Parts List
HPLD Recommended Spare Parts List.....................................................................................................8-1
HPLD Compressor Kits ...........................................................................................................................8-2
Gaterotor Kits.............................................................................................................................8-2
Shaft Seal Kit ..............................................................................................................................8-2
Compressor Gasket and O-Ring Kit.............................................................................................8-2
Tool Kit.......................................................................................................................................8-2
Suction Covers ......................................................................................................................................8-3
Discharge Manifold ...............................................................................................................................8-4
Housing ................................................................................................................................................8-5
Appendices
Appendix A Torque Specifications......................................................................................................A-1
Appendix B Vilter Oil .........................................................................................................................B-1

Table/Figure Page Number
TOC − 4 HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Table of Contents
List of Tables and Figures
Tables
Table 2-1. HPLD Compressor Specifications............................................................................................2-1
Table 2-2. HPLD Compressor Volume Ratio Options ...............................................................................2-3
Table 3-1. Bare Shaft Compressor Weights.............................................................................................3-1
Table 5-1. Maintenance/Service Schedule ..............................................................................................5-1
Table 5-2. Maximum Main Rotor Bearing Clearance................................................................................5-7
Table 5-3. Maximum Gaterotor Bearing Clearance..................................................................................5-9
Table 5-4. Gaterotor Float ......................................................................................................................5-11
Table 5-5. Backlash Range ......................................................................................................................5-13
Table 5-6. HPLD Shaft Seals ....................................................................................................................5-25
Table 5-7. Torque Specifications (All units, Ft.-Lbs) .................................................................................5-28
Table 6-1. Troubleshooting Guide - General Problems and Solutions.......................................................6-1
Figures
Figure 2-1. Basic Single Screw Compressor System ................................................................................2-4
Figure 2-2. Tubing Line To Pressurize The Unit (Bypassing The Compressor) ...........................................2-5
Figure 3-1. Rigging and Lifting Points (Top View) ...................................................................................3-1
Figure 3-2. Additional Instruments.........................................................................................................3-5
Figure 4-1. Compressor and Model Setup with Vission 20/20 .................................................................4-2
Figure 5-1. Oil Analysis Kit (VPN 3097A).................................................................................................5-3
Figure 5-2. Oil Sampler Valve (VPN #3708A) For Gas Compression Applications .....................................5-4
Figure 5-3. Oil Sampling Valve (VPN #3709A) For Ammonia and Refrigerant Compressors .....................5-4
Figure 5-4. Operating the Oil Sampling Valve .........................................................................................5-5
Figure 5-5. Stages of the Oil Sample Taking Process ...............................................................................5-5
Figure 5-6. Bearing Radial Clearance Inspection .....................................................................................5-7
Figure 5-7. Bearing Axial Clearance Inspection .......................................................................................5-8
Figure 5-8. Gaterotor Bearing Clearance ................................................................................................5-9
Figure 5-9. Gaterotor and Shelf Clearance ..............................................................................................5-10
Figure 5-10. Gaterotor and Shelf Clearance Measurement Steps.............................................................5-10
Figure 5-11. Visual Inspection Between Gaterotor and Bushing..............................................................5-11
Figure 5-12. Gaterotor Float Dial Location..............................................................................................5-11
Figure 5-13. Gaterotor Float...................................................................................................................5-12
Figure 5-14. Alignment of Gaterotor ......................................................................................................5-12
Figure 5-15. Location of Dial Indicator Magnetic Base.............................................................................5-12
Figure 5-16. Placement of Dial Indicator.................................................................................................5-13
Figure 5-17. Measuring Backlash............................................................................................................5-13
Figure 5-18. Chipped Edge of Gaterotor .................................................................................................5-14
Figure 5-19. Rotor Position for Gaterotor/Support Assembly Removal....................................................5-15
Figure 5-20. Gaterotor/Support Assembly Removal ...............................................................................5-15
Figure 5-21. Gaterotor Assembly............................................................................................................5-16
Figure 5-22. Tool (A24061A) To Handle Suction Tee Assembly ...............................................................5-17
Figure 5-23. Tool To Remove Bearing Housing Assembly ........................................................................5-18
Figure 5-24. Tool To Install and Remove Bearing Housing Assembly........................................................5-18

TOC − 5
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Table of Contents
Table/Figure Page Number
Figure 5-25. Tool To Install Bearing Housing Assembly ...........................................................................5-19
Figure 5-26. Check the Clearance Between the Gaterotor and Shelf........................................................5-20
Figure 5-27. Gaterotor and Support Assembly........................................................................................5-21
Figure 5-28. Gaterotor Top Face Identification........................................................................................5-21
Figure 5-29. Gaterotor Ball Bearing ........................................................................................................5-22
Figure 5-30. Gaterotor Roller Bearing Assembly .....................................................................................5-23
Figure 5-31. Shaft Seal Assembly............................................................................................................5-24
Figure 5-32. Handling Seal Face with Care ..............................................................................................5-24
Figure 5-33. Shaft Seal Breakdown.........................................................................................................5-25, 5-27
Figure 5-34. Shaft with Pin .....................................................................................................................5-26
Figure 5-35. Shaft Seal Housing..............................................................................................................5-26
Figure 5-36. The Alignment of Compressor Shaft and Mating Ring .........................................................5-26

TOC − 6 / Blank HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP

1 – 1
Section 1 • General Information
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
How To Use This Manual
This manual contains instructions for HPLD bare shaft
compressors. It has been divided into eight sections and
Appendices:
Section 1: General Information
Section 2: Theory of Operation
Section 3: Installation
Section 4: Operation
Section 5: Maintenance & Service
Section 6: Troubleshooting
Section 7: Warranty and Parts
Section 8: Spare Parts List
Appendices
Appendix A - Torque Specications
Appendix B - Vilter Oil
It is highly recommended that the manual be reviewed
prior to servicing system parts.
Figures and tables are included to illustrate key concepts.
Safety precautions are shown throughout the manual.
They are dened as the following:
NOTICE - Notice statements are shown when there are
important information that shall be followed. Not fol-
lowing such notices may result in void of warranty, seri-
ous nes, serious injury and/or death.
WARNING - Warning statements are shown when there
are hazardous situations, if not avoided, will result in se-
rious injury and/or death.
CAUTION - Caution statements are shown when there
are potentially hazardous situations, if not avoided, will
result in damage to equipment.
NOTE - Notes are shown when there are additional infor-
mation pertaining to the instructions explained.
Additional Important Notes
• Installation, operation and maintenance instructions
can be found in the associated software manual.
• Due to continuing changes and unit updates, always
refer to the website Emerson.com/Vilter to make
sure you have the latest manual.
• Any suggestions of manual improvements can
be made to VilterTM Manufacturing at the contact
information on page iii.

1 – 2
Section 1 • General Information
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
System Unit Identication
To keep denitions of units simple and consistent, Vilter has dened the following three:
• Bare Shaft Compressor
• Compressor Unit
• Package Unit
Bare Shaft Compressor
A bare shaft compressor is just the compressor with no coupling and motor nor foundation.
Compressor Unit
A compressor unit consists of the bare shaft compressor with the coupling, motor, oil separator, frame, micro-control-
ler system and oil system. A compressor unit typically a single screw compressor unit, is not mounted on a structural
steel base.
Package Unit
A package unit is a complete system mounted on a structural steel base with interconnecting piping.

1 – 3
Section 1 • General Information
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
VSG–160–STH–STD–FV–AFH–SS
Compressor Type
STH = Steel Compressor
Material w/ Discharge
Connection Horizontal
Special Designations
SS = Stainless Steel Internal
Hardware
C = Ceramic Bearings
EO = External Oil Feed
VIB = Main Housing with
Vibration Mounting
N = 900# Flange
Drive Shaft Type
STD = Standard
Straight Drive Shaft
Slide Design Type
FV = Fixed Volume
Size
CFM = Nominal CFM displacement
of the compressor at 3600 rpm
128, 145, 160, 180, 204, 222, 243
Seal Type
AF = Aas O-rings
HV = High Pressure
Design w/ Viton O-rings
AHF = Ammonia
Service High Pressure
Aas O-ring
Compressor Model
VSG= Vilter Single
Screw Compressor
(Gas Compression)
VSH = Vilter Single
Screw Heat Pump
VSS= Vilter Single
Screw Compressor
(Refrigeration)
Bare Shaft HPLD Compressor Model Designations
The compressor bare shaft model designation can be found on the nameplate.

1 – 4 / Blank HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP

2 – 1
Section 2 • Theory of Operation
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Table 2-1. HPLD Compressor Specications
COMPRESSOR MODEL
VSG128
VSH128
VSS128
VSG145
VSH145
VSS145
VSG160
VSH160
VSS160
VSG180
VSH180
VSS180
VSG204
VSH204
VSS204
VSG222
VSH222
VSS222
VSG243
VSH243
VSS243
DISPLACEMENT AT 3560 RPM (CFM) 128 145 160 180 204 222 243
MAXIMUM ESTIMATED
HORSEPOWER AT 3550 RPM 865
Introduction
Vilter’s HPLD Single Screw Compressors are designed to
t high pressure applications, with special emphasis on
those using CO2 (both transcritical and subcritical), but
including as well gas compression applications and in-
dustrial heat pumps. See Table 2-1 for specications.
The use of constant torque VFD to control the compres-
sor’s capacity saves energy by matching variable load
requirements, which, added to its low displacement,
provides inherent efciency under part-load conditions.
On top of that, VFD capacity control has the advantage
of providing natural soft starts, preventing any type of
surges and transients from being present at start-up.
CO2 Applications
Working at high pressure (for both suction and dis-
charge) gives HPLD compressors the option to use CO2
as refrigerant, and to take advantage of all its features.
High Pressure Applications
HPLD compressors are suited for applications that re-
quire high pressure.
Heat Pump Applications
With a housing designed to withstand high pressures,
and reliable bearings when handling the higher loads of
heat pump applications, plus exibility when choosing
the type of refrigerant to be used, HPLD compressors are
a good match for these applications.
Compressor
The Vilter HPLD Single Screw Compressor is a positive
displacement, capacity and volume controlled, oil ood-
ed, rotary compressor which uses a single main screw
intermeshed by two opposing gaterotors. Gas compres-
sion occurs when the individual teeth of each gaterotor
sweep through the grooves, or utes, of the main screw
as the screw rotates.
Compression occurs from the time the screw ute is rst
closed off by the gaterotor nger, until the time when
the screw ute has rotated to the point of lining up with
the discharge port in the compressor housing. A laby-
rinth type seal is used to prevent gas at discharge pres-
sure from leaking past the end of the screw. Any dis-
charge gas leakage past the labyrinth seal is vented back
to suction via four longitudinal holes drilled through the
body of the screw.
By venting the discharge end of the main screw back to
suction, forces on each end of the screw are equal. This
results in zero net axial forces on the main bearings. With
twin opposing gaterotors, all radial forces are cancelled
out also. Main shaft bearings have no net forces except
the weight of the screw and the shaft assembly.
HPLD compressors are comprised of three rotating
assemblies: the main screw assembly and the two
gaterotor assemblies. Each of these rotating assemblies
use a common bearing configuration consisting of a
single, cylindrical rolling element bearing at one end, and
three angular contact ball bearings at the other end. The
three angular contact ball bearings are used to axially x
one end of the rotating shafts, and to absorb the thrust
loads on the shafts. The inner races of the ball bearings are
securely clamped to the rotating shafts, while the outer
races are securely held in the bearing housing, thus xing
the axial position of the shaft in relation to the bearing
housings. The cylindrical roller bearings at the opposite
end of the shafts allow for axial growth of the shafts while
supporting the radial loads from the shafts.

2 – 2
Section 2 • Theory of Operation
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
The suction gas enters the compressor housing through
the inlet ange, at the driven end of the unit. The driven
end of the compressor housing is ooded with gas at
suction pressure. The gas enters the open end of the main
screw utes at the driven end, and becomes trapped in the
screw ute as the screw rotates and the gaterotor tooth
enters the end of the ute. At this point, the compression
process begins. Directly after the screw ute is closed off
by the gaterotor tooth, oil is injected into the groove.
The oil enters the compressor through a connection at the
top of the compressor. The purpose of the injected oil is
to absorb the heat of compression, to seal the gaterotor
tooth in the groove, and to lubricate the moving parts.
Additional internal oiling ports are provided at the main
and gaterotor bearings to cool and lubricate the bearings.
The mechanical shaft seal housing also contains oiling
ports to lubricate, cool and provide a sealing lm of oil
for the mechanical shafts seal. This oil is directed at the
main rotor roller bearing, which cools and lubricates the
front roller bearing.
As the main screw rotates, the gaterotor is also driven,
causing the gaterotor tooth to sweep the groove in the
main screw. This sweeping action reduces the volume
of the groove ahead of the gaterotor tooth and causes
the trapped gas and oil to be compressed in the reduced
volume. As the main screw continues to rotate, the
gaterotor tooth continues to reduce the groove volume
to a minimum, thus compressing the trapped gas to
a maximum pressure. A labyrinth seal arrangement
prevents the compressed gas from leaking past the end of
the screw. As the gaterotor tooth reaches the end of the
groove, the groove rotates to a position that lines up with
the discharge port in the compressor housing and the gas/
oil mixture is discharged from the screw at high pressure.
This completes the compression cycle for a single ute
of the main screw.
Once the gas is swept from the main screw ute through
the discharge port, it passes into the discharge manifold
of the compressor. From the discharge manifold, the gas/
oil exits the compressor housing.
Capacity and Volume Control
The Vilter HPLD compressor’s capacity is driven by a
variable frequency drive (VFD), which responds to a con-
troller’s commands based on the feedback provided by
readings from instruments and gauges placed on the
system. When the controller drives the VFD to its maxi-
mum speed (100% position), the compression process
begins immediately after the gaterotor tooth enters the
screwute and closes off the end of the groove. In this
situation, the maximum volume of gas is trapped in the
screw ute at the start of the compression process.
As the speed of the VFD reduces, this causes a reduced
volume of gas to be trapped in the screw ute when the
compression process begins. In this way, the capacity of
the compressor is reduced from 100% down to as low as
10% of the full rated capacity.
The use of VFD provides the means to control based on
specific process setpoints. By continuously adjusting
the ow of gas through the compressor, either suction
or discharge pressure in a particular process can be
controlled.
When coupled with a micro-processor controller, the
adjustable speed of the VFD allows for precise and
continuous automatic control of any parameter in the
process to a chosen setpoint.
The compressor’s volume is controlled by different ratio-
sized plugs, thus determining a specic xed volume
ratio for the compressor. Once the volume ratio has
been chosen and the plug placed, this value would be
established.
See Table 2-2 for the different volume ratio options for
HPLD compressors.

2 – 3
Section 2 • Theory of Operation
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Table 2-2. HPLD Compressor Volume Ratio Options
COMPRESSOR MODEL
VSG128
VSH128
VSS128
VSG145
VSH145
VSS145
VSG160
VSH160
VSS160
VSG180
VSH180
VSS180
VSG204
VSH204
VSS204
VSG222
VSH222
VSS222
VSG243
VSH243
VSS243
Volume Rao
8.3 7.3 6.5 6.1 5.1 5.3 4.8
5.3 4.9 4.5 4.2 3.6 3.6 3.5
3.9 3.6 3.4 3.2 2.8 2.9 2.7
2.5 2.5 2.3 2.2 2 2 1.9
1.9 1.9 1.9 1.8 1.6 1.6 1.6
Description of a Gas System For a
Standard Compressor Set
The gas passes through a stop valve and a check valve
and then through a mesh strainer mounted directly to
the inlet ange. The check valve is necessary to prevent
reverse rotation and potential damage or oil loss at shut
down. The suction gas enters the compressor housing
through the inlet ange, at the driven end of the unit.
After compression, the gas is discharged from the
discharge manifold directly into a oil separator tank. On
the discharge of the oil separator tank another check
valve is positioned to prevent the entry of gas or liquid
refrigerant in to the separator when the compressor is
shut down. The separator should be allowed to equalize
slowly to suction pressure through a small bypass line
around the suction check or combination stop/check
valve. This will allow the compressor to start without a
pressure differential across it, reducing the starting power
requirements.
From the discharge manifold, the gas/oil exits the
compressor housing and passes into the oil separator
through a pipe elbow. The separator vessel serves to
separate the oil from the gas as the gas stream moves
from one end of the separator to the other. The majority
of the oil is separated from the gas in the primary chamber
of the vessel due to changes in direction and velocity
reduction. Any remaining oil mist is separated from the
gas stream as the stream passes through the coalescing
elements and into the secondary chamber of the vessel.
The gas at discharge pressure then exits at the far end of
the separator.
Oil collected in the bottom of the separator is drained
off to be recirculated in the oil injection system. The
injection oil temperature is controlled by several means
the rst of which is a three-way mixing valve, which mixes
hot oil directly from the separator with oil which has
passed through the oil cooler to obtain oil at the desired
temperature.
This oil then passes through a filter to remove any
contaminants, which may have been picked up from the
process gas, and is injected back into the compressor.
Description of an Oil System For a
Standard Compressor Set
At the start, oil is drawn from the oil separator tank by
the oil pump, and passes through a oil cooler and mi-
cronic lters to the oil supply inlet on the compressor
frame. From there it lubricates all points internal to the
compressor. After start-up, when the compressor devel-
ops sufcient differential pressure, the oil pump can be
shut down and the oiling can take place without the use
of the oil pump. On units with low pressure differentials
such as booster and low pressure differential high stage
compressors, the oil pump must remain on whenever
the unit is running to maintain sufcient oil ow.

2 – 4
Section 2 • Theory of Operation
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Figure 2-1. Basic Single Screw Compressor System
Critical Application Guidelines
To ensure the successful operation of the HPLD
compressor, the guidelines described below should be
followed.
1. Proper lubrication is critical to the operation of
the HPLD compressor. The compressor relies on
the injected oil to absorb and remove the heat of
compression, to seal the compression chambers
formed in the utes of the screw, and to lubricate all
moving parts. For this reason, it is imperative that the
oil chosen be of correct viscosity, and that sufcient
oil ow be provided at all times, using an auxiliary
oil pump when necessary. The oil chosen must be
compatible with the process gas as well, to prevent
absorption of the gas into the oil, which would dilute
the oil and reduce the viscosity. Also, oil ltration to
25 micron nominal particle size is required to ensure
that only clean oil is injected into the compressor.
For assistance in choosing the correct oil for the
application and in sizing an auxiliary oil pump, consult
a VilterTM representative.
2. Injection oil temperature must be closely controlled
for optimum performance. Oil temperature must
be maintained a minimum of 15 - 20°F above
the gas mixture dew point at anytime to prevent
condensation or liquid knockout from occurring
within the compressor.
Note for CO2 and Heat Pump Applications
Because the oil system on the HPLD compressors utilizes
discharge gas pressure as the means to move the injection
oil through the system, it must be remembered that all
components of the oil system are exposed to full discharge
pressure and must be pressure rated accordingly.
3. Gas composition plays a role in the performance of the
HPLD compressor as well. While the HPLD is capable
of handling a wide variety of gases, it is required that
the concentration of H2S in the process gas not exceed
100 PPM. If H2S is present in the process gas in any
concentration, special oil additives are required to
protect the compressor from corrosion.