DH Instruments PG7607 - 2006 User manual

© 2006 DH Instruments, Inc.
PG7607 PISTON GAUGE
Operation and Maintenance Manual
(Use with PG7000 Operation
and Maintenance Manual)

PG7607™ Operation and Maintenance Manual
© 2006 DH Instruments, Inc.
High pressure liquids and gases are potentially hazardous. Energy stored in these liquids and gases can
be released unexpectedly and with extreme force. High pressure systems should be assembled and
operated only by personnel who have been instructed in proper safety practices.
©1999 - 2006 DH Instruments, Inc. All rights reserved.
Information in this document is subject to change without notice. No part of this document may be reproduced or
transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written
permission of DH Instruments, Inc. 4765 East Beautiful Lane Phoenix AZ 85044-5318 USA.
DH Instruments makes sincere efforts to ensure accuracy and quality of its’ published materials; however, no
warranty, expressed or implied, is provided. DH Instruments disclaims any responsibility or liability for any direct or
indirect damages resulting from the use of the information in this manual or products described in it. Mention of any
product or brand does not constitute an endorsement by DH Instruments of that product or brand. This manual was
originally composed in English and was subsequently translated into other languages. The fidelity of the translation
cannot be guaranteed. In case of conflict between the English version and other language versions, the English
version predominates.
Products described in this manual are manufactured under international patents and one or more of the following U.S.
patents: 6,701,791, 5,142,483, 5,257,640, 5,331,838, 5,445,035. Other U.S. and international patents pending.
DH Instruments, DH, DHI, PG7000, PG7607 and CalTool are trademarks, registered and otherwise, of
DH Instruments, Inc.
Swagelok is a registered trademark of the Swagelok Company
Krytox and Viton are trademarks of the Dupont de Nemours Company
Document No. 550109c-02
070810
Printed in the USA.

PG7607™ Operation and Maintenance Manual
Page i © 2006 DH Instruments, Inc.
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TABLE OF CONTENTS................................................................................I
TABLES....................................................................................................II
FIGURES ..................................................................................................II
ABOUT THIS MANUAL..............................................................................III
1. INTRODUCTION.................................................................................... 1
1.1 PRODUCT OVERVIEW .............................................................................................................................1
1.2 SPECIFICATIONS .....................................................................................................................................2
1.2.1 GENERAL SPECIFICATIONS ...........................................................................................................................2
1.2.2 PISTON-CYLINDER ASSEMBLY......................................................................................................................2
1.2.3 PRESSURE MEASUREMENTS ........................................................................................................................3
2. INSTALLATION..................................................................................... 5
2.1 UNPACKING AND INSPECTION ..............................................................................................................5
2.1.1 REMOVING FROM PACKAGING......................................................................................................................5
2.1.1.1 PISTON-CYLINDER ASSEMBLY......................................................................................................5
2.1.2 INSPECTING CONTENTS.................................................................................................................................6
2.1.2.1 PG7607 PLATFORM .........................................................................................................................6
2.1.2.2 PISTON-CYLINDER ASSEMBLY......................................................................................................7
2.2 INITIAL SETUP..........................................................................................................................................7
2.2.1 CCP PRESSURE CONNECTION......................................................................................................................7
2.2.2 INSTALLING AND REMOVING THE PISTON-CYLINDER ASSEMBLY..........................................................7
3. OPERATION ....................................................................................... 11
3.1 CONTROLLED CLEARANCE PRESSURE (CCP)..................................................................................11
3.2 [HEAD].....................................................................................................................................................11
4. MAINTENANCE, ADJUSTMENTS AND CALIBRATION ............................ 13
4.1 PISTON-CYLINDER ASSEMBLY AND DISASSEMBLY ........................................................................13
4.2 CLEANING PISTON-CYLINDERS...........................................................................................................14
4.3 PISTON-CYLINDER RECALIBRATION..................................................................................................14
4.3.1 MASS OF THE CYLINDER..............................................................................................................................14
4.4 DISASSEMBLY OF PISTON RETAINING ASSEMBLY..........................................................................14
4.4.1 DISASSEMBLY PROCEDURE........................................................................................................................15
4.4.2 REASSEMBLY PROCEDURE.........................................................................................................................16
5. TROUBLESHOOTING .......................................................................... 19
5.1 OVERVIEW..............................................................................................................................................19

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Table 1. PG7607 Parts List .........................................................................................................................6
Table 2. 50 mm Gas Piston-Cylinder Assembly Parts List..........................................................................7
Table 3. PG7607 Troubleshooting Checklist.............................................................................................19
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Figure 1. Piston-Cylinder Installation ........................................................................................................10
Figure 2. Piston Retainer Assembly..........................................................................................................16

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This manual is designed to be used in conjunction with the PG7000 Piston Gauges Operation and
Maintenance Manual, to operate a PG7607 Piston Gauge.
PG7607 is identical in conception and features to a PG7601 piston gauge. PG7607 differs only in the
piston-cylinder mounting post and the piston-cylinder module as PG7607 is designed to exploit a
unique 50 mm diameter piston-cylinder. This manual covers the aspects of PG7607 that are different
from PG7601.
To operate a PG7607, use the PG7000 Piston Gauges Operation and Maintenance Manual and
follow the instructions and information applying to PG7601. Refer to this manual for details on the
piston-cylinder mounting post and piston-cylinder module.
In PG7607, the CYLINDER rather than the PISTON floats and is rotated. When using the PG7000
Manual to operate PG7607, references to the PISTON of PG7601 apply to the CYLINDER of PG7607.
Manual Conventions
(CAUTION) is used in throughout the manual to identify user warnings and cautions.
(NOTE) is used throughout the manual to identify operating and applications advice and
additional explanations.
[ ] indicates direct function keys (e.g., [RANGE]).
< > indicates PG7000 screen displays (e.g., <1yes>).

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PG7607™ Operation and Maintenance Manual
Page 1 © 2006 DH Instruments, Inc.
1. INTRODUCTION
1.1 PRODUCT OVERVIEW
PG7607 is a special model in the PG7000 line of piston gauges. PG7607 is identical to PG7601
except for its piston-cylinder and mounting post.
PG7607 was designed to exploit a unique 50 mm diameter piston-cylinder. With this piston-cylinder,
the piston is mounted in a fixed position in the mounting post and the cylinder floats and is rotated.
A controlled clearance pressure can be introduced into the mounting post allowing the piston
diameter and thus the gap between the piston and cylinder to be varied.
PG7607 is available on a limited basis and, generally, is only offered for use in national measurement
institutes or other laboratories performing fundamental research in pressure metrology.
This manual is intended to be used as a supplement to the PG7000 Manual. PG7607 is identical to
PG7601 except for its piston-cylinder and mounting post. To operate a PG7607, use a PG7000
Operation and Maintenance Manual and apply the information on PG7601 referring to this manual for
piston-cylinder and mounting post information. Also keep in mind that in PG7607, the CYLINDER,
rather than the PISTON, floats and is rotated. References to the PG7601 PISTON in the PG7000
Manual apply to the CYLINDER of PG7607.

PG7607™ Operation and Maintenance Manual
© 2006 DH Instruments, Inc. Page 2
1.2 SPECIFICATIONS
1.2.1 GENERAL SPECIFICATIONS
Specifications below are specific to PG7607. All other specifications are identical to PG7000
specifications found in the PG7000 Operation and Maintenance Manual (P/N 550099).
Weight
Instrument platform with no
mass loaded.
17 kg (29 lb)
Overall Pressure Ranges
with 35 kg mass set Gauge: 5 to 175 kPa (0.7 to 25.4 psi)
Absolute: 5 to 175 kPa (0.7 to 25.4 psi)
Operating Medium Clean, dry, non-corrosive gas
Maximum Mass Load 35 kg (38 kg with AMH automated mass handler)
Pressure Connections
TEST Port
Bell Jar Vent Port
Piston Controlled Clearance
Pressure (CCP)
Vacuum Reference Ports
CE Conformance
DH200
DH200
DH200
NOTE: DH200 is a gland and collar type fittings for 1/4 in.
(6 mm) coned and left hand threaded tubes equivalent to
AE SF250C, HIP LF4, etc.
KF25 on platform and bell jar (KF40 available on optional
AMH automated mass handler)
Available, must be specified.
1.2.2 PISTON-CYLINDER ASSEMBLY
The piston is mounted in a fixed position on the mounting post. The cylinder floats and
is rotated.
Piston Material: Tungsten carbide
Cylinder Material: Tungsten carbide
Nominal Diameter: 50 mm
Nominal Area: 2 000 mm2
Mounting System: Free deformation with controlled clearance pressure
(CCP) available on inside of piston.
Typical Drop Rate:
Full mass load < 0.1 mm/min

PG7607™ Operation and Maintenance Manual
Page 3 © 2006 DH Instruments, Inc.
1.2.3 PRESSURE MEASUREMENTS
The piston is mounted in a fixed position on the mounting post. The cylinder floats and
is rotated.
Sensitivity1:0.01 Pa + 0.5 ppm
Reproducibility2:± 2 ppm
1 Sensitivity: The smallest variation in input detectable in output.
2 Reproducibility: Combined long term stability of piston-cylinder effective area and masses.

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PG7607™ Operation and Maintenance Manual
Page 5 © 2006 DH Instruments, Inc.
2. INSTALLATION
2.1 UNPACKING AND INSPECTION
2.1.1 REMOVING FROM PACKAGING
PG7607 is delivered (along with its standard accessories) in a reusable molded transit case
with polyurethane inserts to hold it in place.
Remove the PG7607 and its accessories from the shipping container and remove each
element from its protective plastic bag.
2.1.1.1 PISTON-CYLINDER ASSEMBLY
The piston-cylinder assembly is shipped in a molded plastic case with custom
polyethylene inserts that accommodates 2 Acetal bullet cases. The piston and the
cylinder are separate; each is packed in its own bullet case. Do not handle either of
these elements with your bare hands. Use the gloves that are in the PG7607
accessory kit or use the lint free wipes.
Never handle the piston or cylinder with bare hands. Oil and acids from bare skin can
damage the critical surfaces (polished appearance).

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© 2006 DH Instruments, Inc. Page 6
2.1.2 INSPECTING CONTENTS
Check that all items are present and have NO visible damage.
2.1.2.1 PG7607 PLATFORM
Table 1. PG7607 Parts List
PG7607
#401385
MOTORIZED ROTATION
NON-CE
PG7607
#401385-CE
MOTORIZED ROTATION
CE
Platform 402360 402360-CE
Mass Bell 402135
Bell Jar W/KF16 401698
Terminal 401284
PG Terminal to Platform Cable
Non-CE (DB25M - DB25F, ≈1.8
meters) 102227
CE (DB25M - DB25F, ≈1.5 meters) 102227-CE
Cable, null modem (for flashing) 402114 402114-CE
Power Cable 100770 100770-CE
Accessory Kit 401049
NIP, SS, DH200, 2.75" 100204
ADPT, SS, DH200 F X 2NPT F 100299
(2) O-ring, Viton, brown, 2-026 101927
O-ring, Viton, brown, 2-019 101930
(2) O-ring, Buna, 2-242 101976
Cover, storage, 7600 type 102132
Allen wrench, 5mm 102262
Krytox™GPL205/6 0.5 oz 102496
Gift kit with gloves 400511
Valve, vacuum relief 401050
Union, SS, 4P 101984
Valve, toggle, 4T, OGS2 103733
ADPT, SS, 4P x 2NPT F 103734
Screen, vent, SS, 2NPT M 103735
ADPT, DH200 M x 4T 400528
Instruction Sht, PG7600 vac relief 560002
Documentation
Calibration Report (PG)
Calibration Report (Mass Bell)
Technical Data
Manuals
Documentation CD
550100
550100
550101
550099 (PG7000)
550109 (PG7607)
102987

PG7607™ Operation and Maintenance Manual
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2.1.2.2 PISTON-CYLINDER ASSEMBLY
Table 2. 50 mm Gas Piston-Cylinder Assembly Parts List
5 kPa/kg
PC-7607-TC
Piston-cylinder kit 401463
Piston-cylinder 401566
Piston-cylinder case (w/ 2 bullet
cases)
402331
Accessory Kit 401568
(2) O-rings, brown, Viton (2-015) 101928
Documentation
Calibration report
550100
2.2 INITIAL SETUP
2.2.1 CCP PRESSURE CONNECTION
The pressure connection labeled CCP is for the application of a controlled clearance
pressure to the inside of the piston (see Section 3.1). In normal operation, the measured
pressure is applied to the CCP pressure connection. Use a tee to connect the TEST port and
the CCP port together.
2.2.2 INSTALLING AND REMOVING THE PISTON-CYLINDER ASSEMBLY
Unlike other PG7000 models, the PG7607 piston-cylinder and mounting elements are not an
integrated module. The piston and cylinder are delivered and installed as separate parts.
Given the large diameter and small annular gap of the PG7607 piston-cylinders, it is very
difficult to insert the piston into the cylinder without the aid of the alignment mechanism
provided by the PG7607 platform mounting post and piston retaining assembly. There is a
risk of cocking the piston in the cylinder. It is not recommended that the piston ever be put
into the cylinder when the piston is not installed on the PG7607 mounting post.
To operate the PG7607 platform, a piston-cylinder must be installed on its mounting post.
To install a piston-cylinder assembly on the PG7607 platform, follow the sequential
procedure below. This procedure may be used on the first and subsequent piston-cylinder
installations; it may also be used in reverse order to remove a piston-cylinder.
Numerical references in the procedure refer to Figure 1.
nRemove the piston retaining assembly (5). The PG7607 platform is delivered with the
piston retaining assembly (5) installed in the mounting post (7). Holding the piston
retaining assembly by the knurled surface (14), unscrew it (rotate CCW) fully from the
mounting post and remove it. Avoid touching the WHITE cylinder centering ring (15) as it
will eventually contact the critical inside surface of the cylinder.
oCheck that the lower piston sealing O-ring (10a) is installed. The PG7607 platform is
delivered with the lower piston sealing O-ring (10a) installed on the mounting post.
Check that the O-ring is present and properly seated. If it is not, install one (two are
included in the PG7607 platform accessory kit).

PG7607™ Operation and Maintenance Manual
© 2006 DH Instruments, Inc. Page 8
pRemove the piston (6) from its packing. Using lint free gloves or wipes to avoid direct
contact with the piston critical surface (polished appearance) remove the piston (6) from
its packing.
Never handle the piston or cylinder with bare hands. Oil and acids from bare skin can
damage the critical surfaces (polished appearance). The cylinder is part of the mass load
and contamination can change its mass.
qInstall the piston (6) on the mounting post (7). With the end of the piston etched with
“X” and/or the serial number UP (11) so that it will enter the cylinder first, slip the piston
over the mounting post. Press the piston down firmly so that it slips over the lower piston
O-ring (10a) and seats on the shoulder just below the O-ring. Check that the end of the
piston facing UP has “X” and/or the serial number marked on it.
rInstall the piston retaining assembly (5). Hold the piston retaining assembly (5) by the
knurled ring (14); avoid touching the white cylinder centering ring (15) as it will eventually
contact the critical inside surface of the cylinder. Thread the piston retaining assembly
into the top of the mounting post (7) and screw it down firmly until the assembly’s
shoulder (13) meets the top of the piston (11) and there is no gap between the
two surfaces. There will be some resistance from the mounting post O-ring (12) and
upper piston sealing O-ring (10b) but only hand tightening is needed. Do not use tools to
install the piston retaining assembly. Tighten lightly by hand until the assembly reaches
the end of the engagement threads and surfaces (13) and (11) meet.
sClean the piston (6) and the cylinder centering ring (15), consider cleaning the
cylinder (4). Using the glass cleaner method described in Section 4.2, clean the
piston
(6) and the cylinder centering ring (15). If this is the first piston-cylinder
installation, also clean the cylinder (4). On subsequent installations consider cleaning the
cylinder before installing it.
tVerify that the cylinder cap O-ring (3) is properly installed. Remove the cylinder (4)
from its packing. It is delivered with the cylinder cap O-ring (3) installed. Check that the
O-ring is present and properly seated. If not, install one (an extra one is included in the
piston-cylinder accessories). Use tweezers or another long narrow tool. DO NOT touch
the inside of the cylinder.
uVerify that the cylinder adjustment mass (17) is properly installed. Check that the
cylinder adjusting mass (17) is present and completely threaded onto the cylinder
retaining screw (2). This mass is used to adjust the total cylinder mass to the value
reported in the calibration report.
vInstall the cylinder (4) on the piston (6). Gently slip the cylinder (4) over the piston (6).
The cylinder centering ring (15) aligns the cylinder on the piston facilitating the
insertion process. Allow the cylinder to slip all the way down the piston until it reaches
end of stroke.

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Page 9 © 2006 DH Instruments, Inc.
wTighten the cylinder retaining screw (2). Using a 5 mm Allen tool (one is supplied in
the PG7607 accessories), tighten the cylinder retaining screw (2) into the cylinder stroke
limiter (16) of the piston retaining assembly (5). Turn the screw CW to tighten. Since the
cylinder stroke limiter (16) is free to move within the piston retaining assembly (5), the
retaining screw (2) may rotate with the assembly, failing to tighten. If this is the case,
press down a bit or lift up on the screw to help it engage and tighten. Tighten gently until
you can feel the cylinder cap O-ring (3) takes its seat in the cylinder stroke limiter.
Be sure the cylinder retaining screw (2) is tightened before applying pressure to the
piston-cylinder. The cylinder stroke limiter (16) limits the cylinder’s upward movement
preventing it from coming off the piston.

PG7607™ Operation and Maintenance Manual
© 2006 DH Instruments, Inc. Page 10
Figure 1. Piston-Cylinder Installation
1. Cylinder Cap
2. Cylinder Retaining Screw
3. Cylinder Cap O-ring (Brown, Viton, 2-015)
4. Cylinder
5. Piston Retainer Assembly/Nut
6. Piston
7. Mounting Post (part of PG7607 platform)
8. Controlled Clearance Pressure (CCP) Inlet
9. Test Pressure Inlet
10a. Piston Sealing O-ring - lower
(Brown Viton, 2-026)
10b. Piston Sealing O-ring – upper
(Brown Viton, 2-026)
11. Piston Top Surface
12. Mounting Post O-ring (Brown, Viton, 2-019)
13. Piston Retainer Assembly Shoulder
14. Knurled Gripping Holding Surface
15. Cylinder Centering Ring
16. Cylinder Stroke Limiter
17. Adjustment Mass

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© 2006 DH Instruments, Inc. Page 11
3. OPERATION
3.1 CONTROLLED CLEARANCE PRESSURE (CCP)
In normal operation, the CCP pressure is the measured pressure. The pressure applied to the TEST
port should also be applied to the CCP port.
PG7607 allows an independent pressure to be applied to the inside of the piston. The purpose of this
feature is to allow the piston to be artificially expanded, varying the size of the gap between the piston
and cylinder. The ability to predictably vary the size of the gap between the piston and the cylinder
can be useful in analyzing piston-cylinder behavior.
The controlled clearance pressure is introduced through the CCP port on the back of the PG7607 platform.
The pressure is applied through the mounting post to the inside of the piston (see Figure 1, Ref. 8). The
pressure is contained by the two piston sealing O-rings (see Figure 1, Refs. 10a, 10b).
The piston sealing O-rings are positioned on the inside of the piston at sufficient distance from the
surface of the piston that is active when the cylinder is engaged so that the deformation due to
pressure along the active zone of the piston is constant and parallel.
The expansion of the piston with pressure can be predicted using thick walled cylinder stress/strain
relations and the mechanical properties of the piston material (tungsten carbide). The result is
0.16 micron on the diameter/MPa.
A typical 50 mm piston-cylinder assembly has a radial gap of 0.9 micron so a CCP of 3 MPa will
reduce the gap by about 50 %. Around 5 MPa, the CCP may close the gap completely causing
mechanical contact between the piston-cylinder and damage to the parts.
A controlled clearance pressure (CCP) of about 5 MPa may close the gap between the piston and
cylinder completely causing metal to metal contact between the two parts and possible damage.
3.2 [HEAD]
The natural reference level for the PG7607 piston-cylinder assembly is near the top of the
cylinder cap. So that, in practice, the actual reference level is at a conveniently identified location, a
reference level offset is applied. The reference level offset places the reference level at the bottom of
the piston. This point is defined by the horizontal line where the bottom of the piston meets the
mounting post when the piston is mounted.
The reference level offset is included in the piston-cylinder file (see PG7000 Operation and
Maintenance Manual).
When using a AMH-38 with the PG7607, the PG7607 reference level is 3 mm below the reference level
marked on the AMH vacuum chamber. This is because the AMH-38 is marked for the PG7601.

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PG7607™ Operation and Maintenance Manual
Page 13 © 2006 DH Instruments, Inc.
4. MAINTENANCE,
ADJUSTMENTS AND
CALIBRATION
4.1 PISTON-CYLINDER ASSEMBLY AND DISASSEMBLY
See the piston-cylinder installation and removal description in Section 2.2.2. The only possible
further disassembly of the piston cylinder is the removal of the cylinder retaining screw and
adjustment mass from the cylinder.
Given the large diameter and small annular gap of the PG7607 piston-cylinders, it is very difficult to
insert the piston into the cylinder without the aid of the alignment mechanism provided by the
PG7607 platform mounting post. There is a risk of cocking the piston in the cylinder. It is not
recommended that the piston ever be put into the cylinder when the piston is not installed on the
PG7607 mounting post.
Disassembly of the piston-cylinder assembly exposes the piston-cylinder to possible damage.
The main risk is damage to the exposed critical working surfaces. Only qualified personnel should
undertake piston-cylinder disassembly and reassembly and the instructions and recommendations
contained in this manual should be followed carefully throughout the operation.
NEVER touch the lapped surfaces (polished appearance) of the piston or cylinder with your bare
hands. Body oils and acids can permanently etch the surfaces.
The cylinder assembly (cylinder + cylinder cap + adjusting mass + cap retaining screw + cylinder
retainer) is part of the PG7607 mass load. Its mass has been measured and is reported in the
calibration report. When handling these parts, take care not to change their mass by swapping parts,
contaminating them or leaving parts out in reassembly.

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© 2006 DH Instruments, Inc. Page 14
4.2 CLEANING PISTON-CYLINDERS
The piston-cylinder cleaning methods described in the PG7000 Operation and Maintenance Manual
should be used with the following exceptions/comments:
•Water/detergent method: Due to the piston-cylinder’s large diameter and very small annular
gap, it is very difficult to insert the piston into the cylinder when the piston is not installed on the
PG7607 mounting post. Without the alignment mechanism provided by the mounting post
arrangement (see Figure 1) there is a substantial risk of cocking the cylinder on the piston.
When using the water/detergent method to clean a PG7607 piston-cylinder, wash the cylinder
and the piston separately and do not attempt to put the piston into the cylinder until the piston is
installed on the PG7607 platform mounting post.
•Quick method: As it is difficult to hold the piston without making contact with its critical working
surface, install the piston onto the PG7607 platform mounting post to clean it (see Section 2.2.2).
4.3 PISTON-CYLINDER RECALIBRATION
4.3.1 MASS OF THE CYLINDER
The floating assembly of the PG7607 cylinder includes (see Figure 1):
•The cylinder and cap (4, 1).
•The cylinder cap screw (2).
•The adjustment mass (17).
•The cylinder cap O-ring (3).
•The cylinder stroke limiter (16).
To determine the mass of the floating cylinder assembly, the mass of all these parts must
be determined. The cylinder stroke limiter (16) is captivated in the piston retaining assembly
(5) and the retaining assembly must be disassembled to remove it. See Section 4.4 for
disassembly instructions for the piston retaining assembly.
4.4 DISASSEMBLY OF PISTON RETAINING ASSEMBLY
The piston retaining assembly (see Figure 2) does not need to be disassembled as part of
routine maintenance. However, the piston retaining assembly captivates the cylinder stroke limiter
that is part of the of cylinder assembly whose mass must be determined when recalibrating
the cylinder.