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Patent 2266806 Summary

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Claims and Abstract availability

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(12) Patent: (11) CA 2266806
(54) English Title: SELF-CONTAINED HYDRAULIC ESD SYSTEM
(54) French Title: SYSTEME ESD HYDRAULIQUE AUTONOME
Status: Expired
Bibliographic Data
(51) International Patent Classification (IPC):
  • F16K 17/00 (2006.01)
  • F15B 20/00 (2006.01)
  • F15B 21/10 (2006.01)
  • F16K 3/26 (2006.01)
(72) Inventors :
  • ELLETT, JAMES RICHARD (Canada)
(73) Owners :
  • ARGUS MACHINE CO. LTD. (Canada)
(71) Applicants :
  • ARGUS MACHINE CO. LTD. (Canada)
(74) Agent: LAMBERT INTELLECTUAL PROPERTY LAW
(74) Associate agent:
(45) Issued: 2003-02-11
(22) Filed Date: 1999-03-23
(41) Open to Public Inspection: 2000-09-23
Examination requested: 2000-05-31
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): No

(30) Application Priority Data: None

Abstracts

English Abstract

A hydraulic control circuit for a hydraulic actuator, including a high-low pilot valve having a sensing port for connection to a flow line. A single pressure line connects the high-low pilot to a hydraulic actuator. A second line connects the high-low pilot to a reservoir. A normally closed relief valve is connected to the single pressure line for relief of excessive pressure. A normally closed override valve is connected to the single pressure line for manual override of circuit controls. A pump is connected to the single pressure line for pressuring the single pressure line. The hydraulic control circuit has a normally open time out valve on the single pressure line, the time out valve being set to close a pre-set time interval after being manually activated, to isolate the high-low pilot, from the single pressure line to the hydraulic actuator, until the time out period has elapsed. The override valve is connected to the single pressure line between the time out valve and the hydraulic actuator. The relief valve is connected to the single pressure line between the time out valve and the hydraulic actuator. The override valve, relief valve, high-low pilot, and the pump are connected between the first line and the reservoir.


French Abstract

Un circuit de commande hydraulique pour un vérin hydraulique, y compris une vanne pilote fort/faible, dotée d'un orifice de détection pour le raccordement à une conduite d'écoulement. Une conduite de pression unique relie la vanne pilote fort/faible à un vérin hydraulique. Une deuxième conduite de pression relie la vanne pilote fort/faible à un réservoir. Une soupape de détente normalement fermée est reliée à une conduite de pression unique, afin d'éviter les surpressions. Un clapet d'interdiction normalement fermé est relié à la conduite de pression unique afin d'assurer l'asservissement manuel des commandes du circuit. Une pompe est reliée à la conduite de pression unique afin de mettre sous pression la conduite de pression unique. Le circuit de commande hydraulique possède une vanne de temporisation sur la conduite de pression unique, la vanne de temporisation étant réglée pour se fermer au bout d'une période d'attente préréglée après avoir été actionnée manuellement, pour isoler la vanne pilote fort/faible, de la conduite de pression unique jusqu'au vérin hydraulique, jusqu'à l'achèvement de la période de temporisation. Le clapet d'interdiction est relié à la conduite de pression unique, entre la vanne de temporisation et le vérin hydraulique. La soupape de détente est reliée à la conduite de pression unique entre la vanne de temporisation et le vérin hydraulique. Le clapet d'interdiction, la soupape de détente, la vanne pilote haut/bas et la pompe sont connectés entre la première conduite et le réservoir.

Claims

Note: Claims are shown in the official language in which they were submitted.



12
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A hydraulic control circuit for a hydraulic actuator, the hydraulic control
circuit
comprising:
a high-low pilot valve having a sensing port for connection to a flow line;
a first line connecting the high-low pilot to a hydraulic actuator, the first
line
forming a single pressure circuit;
a second line connecting the high-low pilot to a reservoir;
a normally closed relief valve connected to the first line for relief of
excessive
pressure;
a normally closed override valve connected to the first line for manual
override of
circuit controls; and
a pump connected to the first line for pressuring the first line.
2. The hydraulic control circuit of claim 1 further comprising a normally open
time
out valve on the first line, the time out valve being set to close for a pre-
set time interval
after being activated.
3. The hydraulic control circuit of claim 1 in which the override valve is
connected to
the first line between the time out valve and the hydraulic actuator.
4. The hydraulic control circuit of claim 1 in which the relief valve is
connected to the
first line between the time out valve and the hydraulic actuator.
5. The hydraulic control circuit of claim 1 in which the override valve,
relief valve and
the pump are connected between the first line and the reservoir.

Description

Note: Descriptions are shown in the official language in which they were submitted.



CA 02266806 1999-06-08
a
1
TITLE OF THE INVENTION
Self Contained Hydraulic ESD System
NAME OF INVENTOR
James Richard Ellett
FIELD OF THE INVENTION
This invention relates to hydraulic emergency shut-down systems (ESD) for
actuating closure of valves.
BACKGROUND OF THE INVENTION
Several emergency shut down systems are known in the art such as the ESD sold
by Erichsen, the ESD sold by Bettis of Houston, USA, the RA PrescoTM-Dyne ESD
sold
by Barber Industries, of Edmonton, Canada, U.S. patent no. 5,341,837 of
Johnson, U.S.
patent no. 4,961,560 of Ellett, U.S. patent no. 5,070,900 of Johnson, U.S.
patent no.
5,213,133 of Ellett, U. S. patent no. 5,291,918 of Johnson, and U. S. patent
no. 5,464,040
of Johnson. These devices typically include a pilot valve that senses pressure
in a flow line.
2 0 When the pressure moves out of a pre-defined range, the pilot valve
signals an actuator to
close a valve and shut down flow in the flow line. These devices typically
have a high
pressure line and a low pressure line. The high pressure line is used to
actuate the actuator,
while the low pressure line is controlled by the pilot valve.
2 5 SUMMARY OF THE INVENTION
The use of dual high and low pressure controls unnecessarily complicates the
design of the ESD. This invention provides a novel ESD that includes a single
pressure line
for control functions at the pilot valve and actuator.
(here is therefore provided in accordance with an aspect of the invention, a
3 0 hydraulic control circuit for a hydraulic actuator, including a high-low
pilot valve having a
sensing port for connection to a flow line. A single pressure line connects
the high-low pilot
to a hydraulic actuator. A second line connects the high-low pilot to a
reservoir. A
normally closed relief valve is connected to the single pressure line for
relief of excessive


CA 02266806 1999-03-23
2
pressure. A normally closed override valve. is connected to the single
pressure line for
manual override of circuit controls. And a pump is connected to the single
pressure line for
pressuring the single pressure line.
In a further aspect of the invention, the hydraulic control circuit has a
normally
open time out valve on the single pressure line, the time out valve being set
to close a
pre-set time interval after being manually activated. In a further aspect of
the
invention, the override valve is connected to the single pressure line between
the time
out valve and the hydraulic actuator. The; relief valve is preferably
connected to the
single pressure line between the time out valve and the hydraulic actuator.
The override
valve, relief valve and the pump are preferably connected between the first
line and the
reservoir.
In addition, this invention provides a novel configuration of pilot valve and
time out
valve.
These and other aspects of the invention axe described in the detailed
description of
the invention and claimed in the claims that fi~llow.
BRIEF DESCRIPTION OF THE DRAWIrfGS
There will now be described preferred embodiments of the invention, with
reference to the drawings, by way of illustration only and not with the
intention of limiting
the scope of the invention, in which like numerals denote like elements and in
which:
2 5 Fig. 1 is a hydraulic schematic of a hydraulic control circuit according
to the
invention;
Fig. 2 is a section through a time out valve for use in the hydraulic circuit
of Fig. 1;
Fig. 3 is a bottom view of the time out valve of Fig. 2;
Fig. 4 is a side view of the time out valve of Fig. 2;
3 0 Fig. S is a section through the time out valve of Fig. 2 with the section
taken at
right angles to the section of Fig. 2; and
Fig. 6 is a detail of a drip valve for use in the time out valve of Fig. 2;


CA 02266806 1999-03-23
3
Fig. 7 is a section through a pilot v~~lve for use in the hydraulic control
circuit of
Fig. 1;
Fig. 8 is a detail of a diaphragm used in the pilot valve of Fig. 7;
Fig. 9 is a is side view of the pilot valve of Fig. 7;
Fig. 10 is a section through a pilot valve similar to the one shown in Fig. 7
but
showing a modification used for high pressure lines; and
Fig. 11 is a section along the line 11-11 of Fig. 7.
DETAILED DESCRIPTION OF PREFERRED EMBOD)IVVIENTS
In this patent document, a reference to "a connection", "connected" or
"connect(s)" is a reference to hydraulic connection unless the context
otherwise requires.
Referring to Fig. 1, there is shown a hydraulic control circuit for an
actuator 20,
which actuates a valve, not shown. A high-low pilot valve 10 is connected to a
flow line 16
to be monitored through port 12 of valve 10 and line 14. A single pressure
line or hydraulic
manifold 18 connects the high-low pilot 10 to the hydraulic actuator 20. The
single pressure
2 0 line 18 has a single pressure along its lengtlh, and thus forms a single
pressure circuit. A
second line 22 connects the high-low pilot 10 to a reservoir 24. A normally
closed relief
valve 26 is connected to the single pressure line 18 through line 28 for
relief of excessive
pressure and drains through line 27 and line 22 to the reservoir 24. A
normally closed
override valve 30 is connected to the single pressure line through line 28 and
29 for manual
2 5 overnde of circuit controls. The line 28 connects to the line 18 between
the time out valve
44 and actuator 20. The override valve 30 drains through line 31 and 22 to the
reservoir
24. A pump 32 is connected to the single pressure line 18 via line 34 and line
28 for
pressuring the single pressure fine. The pump 32 is preferably a hand pump,
and is
separated from the line 28 by a filter 36 and a leak tight outlet check valve
38, both on line
3 0 34. The pump 32 is also connected via line 4~0 with inlet check valve 42
to reservoir 24.
When the pump 32 is activated, fluid moves from reservoir 24 through lines
40, 34 and 28 into line 18. The relief valve 26 and overnde valve 30 block
return of
fluid to reservoir 24, and thus pressure builds up in line 18 when the pump 32
is


CA 02266806 1999-03-23
4
activated. The time out valve 44 is normally open, and is set to close a pre-
set time
interval after being manually activated. The time out valve 44 is described in
more detail in
relation to Figs. 6-10. A filter 46 is also provided on the single pressure
line 18, along with
a fusible plug 48.
The hydraulic control circuit works as follows. The high-low pilot 10 monitors
pressure in the flow line 16 and is nornially closed. When the pressure
exceeds a high set
point or is lower than a low set point, the pilot valve 10 opens, and
hydraulic fluid drains
from line 18 and 22 into reservoir 24. Loss of pressure at the actuator 20
causes the
actuator 20 to close its associated valve. If the pressure in lines 28 or 18
becomes too high
itself; then relief valve 26 opens, until the pressure returns to normal. The
actuator 20 can
be activated manually by operation of the override valve 30. If the
temperature becomes
too high, fusible plug 48 opens to allow line l8 to drain and activate the
actuator 20.
To set the actuator 20 initially, ;pressure must be built in line 18. This is
accomplished initially by closing time out valve 44. High low pilot 10 is open
with low line
pressure being sensed. The time out valve 44~ begins to count down towards
opening. How
2 0 it does this is described in relation to Figs. E.-10. While time out valve
44 is closed, pump
32 is activated to increase the pressure in lines 18 and 28 until actuator 20
is activated.
Activation of actuator 20 will lead to increa:>e of pressure in flow line 16,
and if the line is
working properly, pressure in line 16 will be in its intended operating range.
Thus, when
valve 44 opens, the high-low pilot 10 will have closed, thus maintaining
pressure in line 18
2 5 and activating the actuator 20 with pressure fin line 18.
The pilot 10 is shown in Figs. 7-10. The pilot 10 is designed to bleed down an
E.S.D. hydraulic circuit when high or low pressures are sensed, such as in an
Oil/Gas
production or pipeline facility. The high and low set points are independently
adjustable to meet predetermined levels, in accordance with the desire of the
3 0 operations personnel. The pilot may be used for high only or low only or
both high and
low in one unit. Several springs can be chosen to provide a broad range of set
points,
in both high and low categories.


CA 02266806 1999-03-23
5 The time out valve 44 is shown in Figs. 2-6. The time-out valve 44 is
located in
the pilot circuit shown in Fig. 1 so that wren start up is required and the
pilot is in the
bleed down position (low line pressure being sensed), the time-out valve can
be closed
preventing bleed down of hydraulic pressure enabling the E.S.D. system to be
pressured up with hydraulic oil.
Referring to Fig. 2, the time-out valve 44 is formed from a body 109, with
head 102. An O-ring 104 is provided between body 109 and head 102. A stem 106
extends through the body 109 and head 102, and is provided with a stem wiper
101 to
keep the stem 109 clean. A piston 107 sits in a cylindrical chamber between
the body
109 and head 102. The stem 106 passes through the piston 107. Springs 103 are
positioned between the head 102 and piston 107 on spring guides 105 O-rings
108,
120 and 118 are provided respectively between the piston 107 and body 109,
between
stem 106 and head 102 and between piston 107 and stem 106. Within the body
109,
the stem 106 sits in inner cage 116 and outer cage 111. Lower O-ring 112 and
upper
O-ring 114 are provided between outer cage 111 and the body 109. Outer cage
111 is
2 0 secured in the body 109 by snap ring 113. The stem 106 is provided with
grooves 150.
An O-ring 115 is provided in the body 10'9 adjacent the grooves 150 in the
stem 106.
An O-ring 117 is provided at the upper e,nd of the inner cage 116 between the
stem
106 and body 109. A pin 119 is provided transversely in the piston 107 to hold
the
piston 107 on the stem 106. The body 1 CI9 is provided with ports 149 and 148.
The
2 5 port 148 communicates with a bore 146 vrhich terminates in an annular
groove 151 in
the body 109 that extends around the stem 109 at the top of the outer cage
111. Bore
146 is plugged on its outer end with plug ll 10. The port 149 communicates
with a bore
152 which terminates in an annular groove 153 in the body 109 that extends
around
the stem 109 at the bottom of the inner cage 116. Bore 152 is plugged on its
outer end
3 0 with plug 110.
Referring to Figs. 4-6, the stem 106 is provided with handle or lever 131
which
is pivotally attached to stem 106 at pivot pin 135. The lever 131 is pivotally
secured to
the head 102 by lever bracket 134 and fulcrum pin 133 which passes through
both the


CA 02266806 1999-03-23
6
lever bracket 134 and the lever 131. A cavpscrew 132 with nut 129 secures the
lever
bracket 134 to the head 102, with the bracket 134 spaced from the head 109 by
spacer
130. Capscrews 136 secure the head 102 to the body 109. Capscrews 128 secure
the
body 109 to a supporting block (not shown). An alignment pin 137 aligns the
piston
107 with respect to the head 102. The chamber 138 above and below the piston
107 is
filled with dampening fluid. A vent plug 13 9, with spring 140 and ball 141,
is provided
at the top of the chamber 138 in head 102, and communicates with the chamber
138
through bore 154. The ball 141 is biased against the terminus of bore 154 in
head 102
by spring 140.
Referring in particular to Fig. 6, the; piston 107 has a metering valve
connecting
between the portions of the chamber 138 above and below the piston 107. The
metering valve is formed from a retainer 121, under which is placed a screen
122 and
insert 123. The insert 123, which is hat shaped, forms a seat for an O-ring
124. An
orifice disc 125, with an orifice in the middle, is placed against the insert
123 and O-
ring 124. A spring 126 is placed between a shoulder 155 on the piston 107 and
the
2 0 orifice disc 125. A snap ring 127 keeps a second screen 122 in place.
When the time-out valve 44 is open, oil can flow up through port 149 in body
109 through inner cage 116, through grooves 150 in stem 106, and through the
outer
cage 111 into port 148 in body 109 to the line 118.
To close the time-out valve, the lever 131 is pushed down. This raises the
stem
2 5 106 so that the grooves 150 do not connect with the inner cage 116 and
outer cage
111 and the hydraulic oil cannot go through the time-out valve 44.
When the time-out valve 44 is closed with the lever 131 pushed down (stem
up), the pilot 10 is timed out of the circuit for as long as it takes for the
time-out valve
44 to open again on its own.
3 0 The time-out valve 44 operation is described as follows: When the stem 106
is
moved up by the lever 131, the piston. 107 moves up with the stem 106 and
compresses piston springs 103. As the piston 107 moves up in the upper bore of
the
body 109, the dampening fluid 138 lifts orifice disc 125 off O-ring 124 around
the


CA 02266806 1999-03-23
7
insert 123, thus allowing fluid to pass so the piston 107 can, in fact, move
up. Upon
releasing the lever 131, the piston springs 103 push down on the piston 107.
The
dampening fluid 138 now has to flow through the seated orifice disc 125 which
delays
the rate that the piston 107 and stem 106 moves downward. This delay causes
the
pilot 10 to be timed-out of the circuit. The duration of time-out can be
determined by
choosing the orifice size in the orifice disc 125 and by choosing a suitable
viscosity for
the dampening fluid 13 8.
The pilot is designed particularly for use with the E.S.D. shown in Fig. 1,
but it
may be used with other systems requiring high and low set points. When the
production/pipeline facility pressure is too high or too low due to failure of
the facility,
the pilot senses this condition and bleeds down E. S.D. system hydraulic
pressure
causing the shut down valve (not shown) to close and prevent product loss. The
pilot
is shown in Figs. 7-10.
The base of the pilot consists of a bottom sub 221, which contains a pressure-
sensing capsule, which is made up of nut :Z 14, upper ring 215, lower ring
216, gasket
2 0 217, diaphragm 218, scrolled support disc 219, and piston 220. The design
and
operation of the pressure sensing system is described in greater detail in
United States
patent no. 5,670,766 of Argus Machine C:o. Ltd., of Edmonton, Canada, from
whom
the product may be purchased. The nut 21.4 is used to hold down the upper ring
215,
and the lower ring 216, which compresses the gasket 217, sealing off the
sensed
2 5 facility pressure against the diaphragm 2l. 8. The scrolled support disc
219 transmits
the diaphragm 218 movement to the piston 220. This design differs slightly
from what
is described in United States patent no. S,E~70,766 by having an increased
piston stroke
which is required to sufficiently open a high poppet 210 and low poppet 224,
to
provide adequate bleed down rate of the hydraulic pressure.
30 Stem 230 transfers movement of tile piston 220 through low base plate 201
to
low pressure spring 237 and at higher prE;ssures through high base plate 228
to high
pressure spring 231. Spool 223 is positioned approximately in an axial
relationship to
the stem 230 by the use of a selection of two spool spacers 206, one above and
one


CA 02266806 1999-03-23
8
below the spool 223, and necessary shims 207 and 213, all retained snugly with
a snap
ring 205. The assembly in this paragraph may be modified to use threads on the
stem
230 and in the spool 223 with a lock nut instead of the snap ring 205.
A top sub 234 is threaded into the bottom sub 221 and holds stop ring 227
down against stop ring shims 226. The number of stop ring shims 226 is
determined by
how many it takes to cause the stem 230 to shoulder up against the high base
plate
228 when the upward travel of the stem ~;30 has reached 50% of its total
travel. This
portion of the travel is called the low pressure travel fixnction, and may be
approximately 0.025". Two set screws 204 are inserted through threaded holes
in the
bottom sub 221 into counterbored holes in the top sub 234 locking them
together.
The high pressure spring 231 is situated between the stop ring 227 and the
high
adjuster ring 232. The high pressure spring 231 is compressed by screwing down
high
adjustment knob 235 against high contact ring 233 which moves down against the
high
load screws 203 moving them down with the high adjuster ring 232. High
pressure
spring 231 controls the high pressure travel fi~nction, namely the top 50% of
the
2 0 upward stem 230 travel.
The low pressure spring 237 is situated between the low base plate 201 and
low adjustment 239. Low pressure spring 237 is compressed by screwing down the
low adjustment 239. The low pressure spring 237 controls the low pressure
travel
function.
Low adjustment cover 238 serves to totally enclose the inner pilot assembly,
as
well as the low adjustment 239, and threads onto the top sub 234. O-rings 211
(between bottom sub 221 and a lower slide of poppet block 209), 225 (between
an
upper side of poppet block 209 and bottom sub 221), 229 (between high
adjustment
knob 23 5 and bottom sub 221 ), and 23 6 (between cover 23 8 and knob 23 5)
seal off
3 0 the outer atmosphere from the inner pilot assembly. O-ring 202 only serves
to hold the
low base plate 201 from falling out of pl;~ce off the stem 230. An elastomeric
U-cup
seal 222 keeps impurities and condensed water vapor out of the lower portions
of the
pilot assembly.


CA 02266806 1999-06-08
9
The operating position of the high poppet 210 is adjusted by activating upper
setting screws 208 and lower setting screws 212, which thread into the poppet
block
209, before tightening block capscrews 240. The same procedure is used to
obtain the
operating position of the low poppet 224. Currently a body breather vent 242
is used
to return the E.S.D. hydraulic oil, bled down by either the high poppet 210 or
the low
poppet 224. Optionally, the poppet blocks 209 may be configured to port the
fluid
bled by the poppets 210 and 224 directly to a return line. A body drain plug
241 is
provided for draining the pilot body. Pressure in from line 18 is provided to
high sense
side of the pilot 12 through port 251, and to low sense side of the pilot 12
through
port 250. Activation of the poppet valves 210 and 224 cause fluid to flow
through the
ports 251 and 250 respectively around the spool 223 between the spool 223 and
the
poppet block 209 and exit the pilot 12 through outlet drain 242, which
connects to line
22. The poppet valves 210 and 224 are of the type typically used as tire stem
valves.
The high and low set points are adjusted separately, the high set point being
affected by subsequent low set point changes. Adjustments of the high set
point do not
2 0 affect the low set point. It is therefore desirable to complete the low
set point
adjustments before completing the high set point adjustment. For high pressure
Oil/Gas production or pipeline applications, an alternate plunger type piston
243
received by collar 244 and packed with packing seals 245 and 246 can be used
instead
of the diaphragm 218, as shown in Fig. 10.
2 5 In an embodiment of the ESD made by Argus Machine Co. Ltd. of Edmonton,
Alberta, Canada, the oil reservoir 24 had a useable volume of 140 cu. in. (200
cu. in. to
fill). The maximum sustained output pressure was 2,000 p.s.i. Automatic
transmission fluid
was used as the hydraulic fluid in line 18 down to -20°F and aircraft
hydraulic oil for below
-20°F. (J-13 Univis). The general operational instructions are: To
start-up system (opening
3 0 gate valve with actuator 20), lift knob on time-out valve 44 (to isolate
pilot signal).
Reciprocate handle of hand pump 32 until valve is open. After the time-out
period has
elapsed, the high-low pilot 10 takes over control of the system. When either
high or low
set points are sensed by the high-low pilot 10, the hydraulic oil pressure is
bled back to tank


CA 02266806 1999-03-23
5 24 causing the actuator 20 to close the gate valve. If it is desired to
close the gate valve
even though sensed flow line pressures are within the set points of the pilot,
simply depress
the knob on the over-ride valve 30. A fi~sihle plug 48 is incorporated into
the system to
automatically bleed the hydraulic oil pressure back to tank in the event of a
fire or
extremely high temperature.
10 To test the high-low pilot 10, use an isolation valve between it and the
flow line 16.
Use a pressure gauge and a hand operatexi hydraulic hand pump to simulate flow
line
pressures and test for both high and low set points.
1. Mount the subject E.S.D. System onto the spring close actuator cylinder 20
with
bracket and clamps (available from Argus Machine Co. Ltd.), and mount the
pressure control pilot 10 on its own test stand adjacent to the E.S.D.
2. Connect the actuator 20, hydraulic manifold 18 and pressure control pilot
10, using
stainless steel tubing and fittings. Use Loctite PST dope on pipe threads
where
applicable.
3. Remove filler cap (pressurelvacuurn type) and 314 fill the hydraulic oil
reservoir
2 0 with J-13 Univis aircraft hydraulic oil. Leave the filler cap off until
air bleeding is
done.
4. Install a temporary pressure gauge (2,000 p.s.i.) on the port, where the
fire safe
fusible plug 48 is normally installed, for this test. (The system relief valve
is set at
1,000 p.s.i.)
2 5 5. The pressure control pilot 10 should be sensing zero pressure at this
time to allow
the air to be displaced from within the system.
6. Activate the lever of the time-out valve 44 & reciprocate the hand pump 32
until
the spring close actuator 20 has fi~ll~r opened the gate valve.
7. Wait for the time-out valve 44 to shift and bleed the pressure from the
actuator 20.
3 0 8. Allow five (S) minutes for the air bubbles to escape from the oil in
the reservoir 24.
9. Apply pressure to the pressure control pilot 10, bringing it into the
operating range
between the high and low set points.
10. Pump up the system again, opening the gate valve.


CA 02266806 1999-03-23
l_ 1
11. Push down on the knob of the over-ride valve 30 and hold it down until the
gate
valve closes.
12. Allow five (5) minutes for the air bubbles to escape from the oil in the
reservoir 24.
13. Repeat Steps 6, 11 and 12. Install the: filler cap.
14. Repeat Step 6 and check the low set point of the pressure control pilot
10.
1 S. Repeat Step 6 and check the high set point of the pressure control pilot
10.
16. Apply pressure to one side of the ;gate valve and check its operation, by
either
cycling the pressure control pilot 10 or, by setting the pilot 10 within the
operating
range and using the over-ride valve 30.
17. Check the leak tight integrity of the ;system by installing a dial
indicator (reading in
0.001" increments) on the stem of the spring close actuator 20 when the gate
valve
is in the open position.
18. The stem of the dial indicator should rest on the head of the spring close
actuator.
Spring close actuator action, from the valve open position, should clear the
dial
indicator after about 0.500" of movement.
2 0 19. The dial indicator dwell position, fo:r the leak tight integrity test,
should be about
0.100" to 0.400" from the fully open gate valve position. Jog the over-ride
valve
30 to obtain this position. 'Zero' the dial and let the system stand for one
hour.
The actuator stem should not shift more than 0.001" during that time. The
system
temperature should be held within ~ S°F during this test.
2 5 20. To speed up the process of determining the cause of leak down, if any,
temporarily
install an instrument valve in the supply line from the hydraulic manifold 18
to the
pilot 10. (In an emergency a 1/4" N.P.T. pipe plug could be installed at the
manifold instead. )
A person skilled in the art could make immaterial modifications to the
3 0 invention described in this patent document without departing from the
essence of the
invention that is intended to be covered by the scope of the claims that
follow.

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date 2003-02-11
(22) Filed 1999-03-23
Examination Requested 2000-05-31
(41) Open to Public Inspection 2000-09-23
(45) Issued 2003-02-11
Expired 2019-03-25

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $300.00 1999-03-23
Registration of a document - section 124 $100.00 1999-06-08
Request for Examination $400.00 2000-05-31
Maintenance Fee - Application - New Act 2 2001-03-23 $100.00 2001-02-06
Maintenance Fee - Application - New Act 3 2002-03-25 $100.00 2002-02-28
Final Fee $300.00 2002-11-29
Maintenance Fee - Patent - New Act 4 2003-03-24 $100.00 2003-03-14
Maintenance Fee - Patent - New Act 5 2004-03-23 $200.00 2004-02-05
Maintenance Fee - Patent - New Act 6 2005-03-23 $200.00 2005-03-04
Maintenance Fee - Patent - New Act 7 2006-03-23 $200.00 2006-03-01
Back Payment of Fees $200.00 2006-03-13
Maintenance Fee - Patent - New Act 8 2007-03-23 $200.00 2007-01-03
Back Payment of Fees $200.00 2007-03-01
Maintenance Fee - Patent - New Act 9 2008-03-24 $200.00 2007-12-07
Maintenance Fee - Patent - New Act 10 2009-03-23 $250.00 2008-12-03
Maintenance Fee - Patent - New Act 11 2010-03-23 $250.00 2009-11-09
Maintenance Fee - Patent - New Act 12 2011-03-23 $250.00 2011-03-21
Maintenance Fee - Patent - New Act 13 2012-03-23 $250.00 2012-02-28
Maintenance Fee - Patent - New Act 14 2013-03-25 $250.00 2013-01-04
Maintenance Fee - Patent - New Act 15 2014-03-24 $450.00 2014-02-10
Maintenance Fee - Patent - New Act 16 2015-03-23 $450.00 2015-03-04
Maintenance Fee - Patent - New Act 17 2016-03-23 $450.00 2016-02-29
Maintenance Fee - Patent - New Act 18 2017-03-23 $450.00 2017-02-02
Maintenance Fee - Patent - New Act 19 2018-03-23 $450.00 2017-12-20
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
ARGUS MACHINE CO. LTD.
Past Owners on Record
ELLETT, JAMES RICHARD
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
Documents

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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Cover Page 2003-01-07 1 44
Representative Drawing 2000-09-18 1 9
Abstract 1999-06-08 1 32
Description 1999-06-08 11 555
Cover Page 2000-09-18 1 42
Abstract 1999-03-23 1 28
Description 1999-03-23 11 546
Claims 1999-03-23 1 34
Drawings 1999-03-23 5 155
Correspondence 2006-06-12 1 2
Prosecution-Amendment 2000-05-31 9 310
Fees 2003-03-14 1 28
Fees 2007-01-03 1 26
Correspondence 2002-11-29 1 26
Correspondence 1999-05-04 1 31
Assignment 1999-03-23 2 68
Assignment 1999-06-08 3 122
Prosecution-Amendment 1999-06-08 5 193
Fees 2004-02-05 1 28
Fees 2006-03-13 1 26
Correspondence 2007-07-09 2 59
Correspondence 2007-07-13 1 14
Correspondence 2007-07-13 1 17
Fees 2007-12-07 1 25
Fees 2008-12-03 1 30
Fees 2009-11-09 1 27
Fees 2011-03-21 1 202
Fees 2012-02-28 1 163
Fees 2013-01-04 1 163
Fees 2014-02-10 1 33
Fees 2015-03-04 1 33
Fees 2016-02-29 1 33
Fees 2017-02-02 1 33