WO2020099888A2

WO2020099888A2 - Lifting apparatus

Info

Publication number: WO2020099888A2
Application number: PCT/GB2019/053244
Authority: WO
Inventors: Michael John Norrington; Mark Robert STACH; Simon Nicholas PETERS; Neil William HARBER; Kevin Frederick OSBORN
Original assignee: Edwards Limited
Priority date: 2018-11-16
Filing date: 2019-11-15
Publication date: 2020-05-22
Also published as: GB2579063A; GB201818732D0; WO2020099888A3; TW202026228A

Abstract

A lifting apparatus (100) for lifting vacuum pumping and/or abatement equipment, the lifting apparatus comprising: a plurality of rams (110a-110d) for engaging with equipment; a plurality of pumps (130a-130d) for pumping fluid to the plurality of rams to cause the plurality of rams to move equipment engaged with the plurality of rams; and a plurality of valves (120a-120k) for controlling the flow of fluid between the plurality of rams and the plurality of pumps, wherein the plurality of rams are connected to the plurality of pumps via the plurality of valves, wherein the lifting apparatus is operable in a first mode in which the plurality of valves are configured such that each of the plurality of rams is in fluid communication with each other ram, and wherein the lifting apparatus is operable in a second mode in which the plurality of valves are configured such that each of the plurality of rams is fluidly isolated from each other ram.

Description

LIFTING APPARATUS

FIELD OF THE INVENTION

The present invention relates to a lifting apparatus for use in vacuum pumping and/or abatement systems.

BACKGROUND

Vacuum pumping and/or abatement systems are used in varied and different technological fields, for example in semiconductor fabrication. Typically, in said systems, vacuum pumping equipment is used to pump gas (e.g. gas from an industrial process) out of a particular place, and abatement equipment is used to abate (e.g. destroy or dispose of) undesirable substances (e.g. exhaust gas) which have been produced.

During installation and/or use of a vacuum pumping and/or abatement system, it may be desirable to lift vacuum pumping and/or abatement equipment in order to move said equipment to a particular location, or to enable repair/maintenance to be performed on said equipment.

SUMMARY OF INVENTION

According to a first aspect, there is provided a lifting apparatus for lifting vacuum pumping and/or abatement equipment, the lifting apparatus comprising: a plurality of rams for engaging with equipment; a plurality of pumps for pumping fluid to the plurality of rams to cause the plurality of rams to move equipment engaged with the plurality of rams; and a plurality of valves for controlling the flow of fluid between the plurality of rams and the plurality of pumps, wherein the plurality of rams are connected to the plurality of pumps via the plurality of valves, wherein the lifting apparatus is operable in a first mode in which the plurality of valves are configured such that each of the plurality of rams is in fluid communication with each other ram, and wherein the lifting apparatus is operable in a second mode in which the plurality of valves are configured such that each of the plurality of rams is fluidly isolated from each other ram.

The plurality of valves may be operable to switch the lifting apparatus between operating in the first mode and operating the second mode.

The lifting apparatus may be operable in a third mode in which the plurality of pumps are off and the plurality of rams move to push fluid towards the plurality of pumps via the plurality of valves.

The lifting apparatus may comprise a first fluid line, a second fluid line and a third fluid line.

The plurality of rams may comprise a first ram and a second ram.

The plurality of pumps may comprise a first pump and a second pump.

The plurality of valves may comprise a first valve, a second valve and a third valve.

The first ram may be connected to the first pump by the first fluid line. The second ram may be connected to the second pump by the second fluid line.

The first fluid line may be connected to the second fluid line by the third fluid line.

The first valve may be disposed on the first fluid line between the first ram and the first pump.

The second valve may be disposed on the second fluid line between the second ram and the second pump.

The third valve may be disposed on the third fluid line.

In the first mode, the first pump may simultaneously pump fluid towards both the first ram and the second ram.

In the second mode, the first pump may pump fluid towards the first ram without pumping fluid towards the second ram and, simultaneously, the second pump pumps may fluid towards the second ram without pumping fluid towards the first ram. The first and second valves may be simultaneously openable to switch the lifting apparatus from operating in the second mode to operating in the third mode.

When the third valve is open, the first ram in may be fluid communication with the second ram.

When the third valve is closed, the first ram may be fluidly isolated from the second ram.

The lifting apparatus may further comprise a first flow restrictor disposed on the first fluid line and a second flow restrictor disposed on the second fluid line.

In the third mode, the first ram may move to push fluid towards the first pump via the first flow restrictor and the second ram may move to push fluid towards the second pump via the second flow restrictor.

The lifting apparatus may further comprise a first bypass valve connected in parallel with the first flow restrictor and a second bypass valve connected in parallel with the second flow restrictor.

According to a second aspect, there is provided a method of operating a lifting apparatus for lifting vacuum pumping and/or abatement equipment, the lifting apparatus comprising a plurality of rams for engaging with equipment, a plurality of pumps for pumping fluid to the plurality of rams to cause the plurality of rams to move equipment engaged with the plurality of rams, a plurality of valves for controlling the flow of fluid between the plurality of rams and the plurality of pumps, wherein the plurality of rams are connected to the plurality of pumps via the plurality of valves, the method comprising: operating the lifting apparatus in a first mode in which the plurality of valves are configured such that each of the plurality of rams is in fluid communication with each other ram; and operating the lifting apparatus in a second mode in which the plurality of valves are configured such that each of the plurality of rams is fluidly isolated from each other ram. The method may further comprise operating the plurality of valves to switch the lifting apparatus between operating in the first mode and operating in the second mode.

The method may further comprise operating the lifting apparatus in a third mode in which the plurality of pumps are off and the plurality of rams move to push fluid towards the plurality of pumps via the plurality of valves.

According to a third aspect there is provided a ram for a lifting apparatus for lifting vacuum pumping and/or abatement system equipment, the ram comprising: a body comprising a first bore and a second bore; a first piston disposed within the first bore, wherein at least a portion of the first piston is movable out of the first bore in a first direction; and a second piston disposed within the second bore, wherein at least a portion of the second piston is movable out of the second bore in a second direction opposite to the first direction.

According to a fourth aspect, there is provided a lifting apparatus in accordance with the first aspect, wherein each of the plurality of rams is a ram in accordance with the third aspect, and wherein the plurality of rams are mechanically coupled together by a frame structure.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a schematic illustration (not to scale) showing a lifting apparatus for lifting vacuum pumping and/or abatement equipment;

Figure 2 is a flowchart showing various steps of a method of operating the lifting apparatus;

Figure 3 is a schematic illustration (not to scale) showing a perspective view of an embodiment of a ram of the lifting apparatus;

Figure 4 is a schematic illustration (not to scale) showing a side view of the ram; and

Figure 5 is a schematic illustration (not to scale) showing a top-down view of a plurality of the rams mechanically coupled together. DETAILED DESCRIPTION

Figure 1 is a schematic illustration (not to scale) showing a lifting apparatus 100 for lifting vacuum pumping and/or abatement equipment.

The lifting apparatus 100 comprises a plurality of rams 1 10a-1 10d, a plurality of valves 120a-120k, a plurality of flow restrictors 121 a-121 d, a plurality of pumps 130a-130d, a plurality of fluid lines 140a-140e, and a plurality of pressure sensors 150a-150d. More specifically, in this embodiment, the lifting apparatus 100 comprises a first ram 1 10a, a second ram 1 10b, a third ram 1 10c, a fourth ram 1 10d, a first valve 120a, a second valve 120b, a third valve 120c, a fourth valve 120d, a fifth valve 120e, a sixth valve 120f, a seventh valve 120g, an eighth valve 120h, a ninth valve 120i, a tenth valve 120j, an eleventh valve 120k, a first flow restrictor 121 a, a second flow restrictor 121 b, a third flow restrictor 121 c, a fourth flow restrictor 121 d, a first pump 130a, a second pump 130b, a third pump 130c, a fourth pump 130d, a first fluid line 140a, a second fluid line 140b, a third fluid line 140c, a fourth fluid line 140d, a fifth fluid line 140e, a first pressure sensor 150a, a second pressure sensor 150b, a third pressure sensor 150c, and a fourth pressure sensor 150d.

The first pump 130a is connected, by the first fluid line 140a, to the first ram 1 10a. The fourth valve 120d and a parallel arrangement of the eighth valve 120h and first flow restrictor 121 a (i.e. an arrangement in which the eighth valve 120h and the first flow restrictor 121 a are connected in parallel with each other) are disposed on the first fluid line 140a between the first pump 130a and the first ram 1 10a. Thus, the first pump 130a and first ram 1 10a are connected to each other via the fourth valve 120d and the parallel arrangement of the eighth valve 120h and first flow restrictor 121 a.

The second pump 130b is connected, by the second fluid line 140b, to the second ram 1 10b. The fifth valve 120e and a parallel arrangement of the ninth valve 120i and second flow restrictor 121 b (i.e. an arrangement in which the ninth valve 120i and the second flow restrictor 121 b are connected in parallel with each other) are disposed on the second fluid line 140b between the second pump 130b and the second ram 1 10b. Thus, the second pump 130b and second ram 110b are connected to each other via the fifth valve 120e and the parallel arrangement of the ninth valve 120i and second flow restrictor 121 b.

The third pump 130c is connected, by the third fluid line 140c, to the third ram 110c. The sixth valve 120f and a parallel arrangement of the tenth valve 120j and third flow restrictor 121c (i.e. an arrangement in which the tenth valve

120j and the third flow restrictor 121 c are connected in parallel with each other) are disposed on the third fluid line 140c between the third pump 130c and the third ram 110c. Thus, the third pump 130c and third ram 110c are connected to each other via the sixth valve 120f and the parallel arrangement of the tenth valve 120j and third flow restrictor 121 c.

The fourth pump 130d is connected, by the fourth fluid line 140d, to the fourth ram 110d. The seventh valve 120g and a parallel arrangement of the eleventh valve 120k and fourth flow restrictor 121 d (i.e. an arrangement in which the eleventh valve 120k and the fourth flow restrictor 121 d are connected in parallel with each other) are disposed on the fourth fluid line 140d between the fourth pump 130d and the fourth ram 110d. Thus, the fourth pump 130d and fourth ram 110d are connected to each other via the seventh valve 120g and the parallel arrangement of the eleventh valve 120k and fourth flow restrictor 121 d.

The first fluid line 140a, second fluid line 140b, third fluid line 140c and fourth fluid line 140d are connected to each other by the fifth fluid line 140e. The fifth fluid line 140e is connected to the first fluid line 140a at a point on the first fluid line 140a between the first pump 110a and the fourth valve 120d. The fifth fluid line 140e is also connected to the second fluid line 140b at a point on the second fluid line 140b between the second pump 110b and the fifth valve 120e. The fifth fluid line 140e is also connected to the third fluid line 140c at a point on the third fluid line 140c between the third pump 110c and the sixth valve 120f. The fifth fluid line 140e is also connected to the fourth fluid line 140d at a point on the fourth fluid line 140d between the fourth pump 110d and the seventh valve 120g.

The first valve 120a is disposed on the fifth fluid line 140e between the point at which the fifth fluid line 140e connects to the first fluid line 140a and the point at which the fifth fluid line 140e connects to the second fluid line 140b. The second valve 120b is disposed on the fifth fluid line 140e between the point at which the fifth fluid line 140e connects to the second fluid line 140b and the point at which the fifth fluid line 140e connects to the third fluid line 140c. The third valve 120c is disposed on the fifth fluid line 140e between the point at which the fifth fluid line 140e connects to the third fluid line 140c and the point at which the fifth fluid line 140e connects to the fourth fluid line 140d.

The first pump 130a is also connected to the second ram 110b via the first valve 120a, the fourth valve 120d, and the parallel arrangement of the eighth valve 120h and first flow restrictor 121 a. The first pump 130a is also connected to the third ram 110c via the first valve 120a, the second valve 120b, the fourth valve 120d, and the parallel arrangement of the eighth valve 120h and first flow restrictor 121 a. The first pump 130a is also connected to the fourth ram 110d via the first valve 120a, the second valve 120b, the third valve 120c, the fourth valve 120d, and the parallel arrangement of the eighth valve 120h and first flow restrictor 121 a.

The second pump 130b is also connected to the first ram 110a via the first valve 120a, the fifth valve 120e, and the parallel arrangement of the ninth valve 120i and second flow restrictor 121 b. The second pump 130b is also connected to the third ram 110c via the second valve 120b, the fifth valve 120e, and the parallel arrangement of the ninth valve 120i and second flow restrictor 121 b. The second pump 130b is also connected to the fourth ram 110d via the second valve 120b, the third valve 120c, the fifth valve 120e, and the parallel arrangement of the ninth valve 120i and second flow restrictor 121 b.

The third pump 130c is also connected to the first ram 110a via the first valve 120a, the second valve 120b, the sixth valve 120f, and the parallel arrangement of the tenth valve 120j and third flow restrictor 121 c. The third pump 130c is also connected to the second ram 110b via the second valve 120b, the sixth valve 120f, and the parallel arrangement of the tenth valve 120j and third flow restrictor 121 c. The third pump 130c is also connected to the fourth ram 110d via the third valve 120c, the sixth valve 120f, and the parallel arrangement of the tenth valve 120j and third flow restrictor 121 c.

The fourth pump 130d is also connected to the first ram 110a via the first valve 120a, the second valve 120b, the third valve 120c, the seventh valve 120g, and the parallel arrangement of the eleventh valve 120k and the fourth flow restrictor 121 d. The fourth pump 130d is also connected to the second ram 110b via the second valve 120b, the third valve 120c, the seventh valve 120g, and the parallel arrangement of the eleventh valve 120k and the fourth flow restrictor 121 d. The fourth pump 130d is also connected to the third ram 110c via the third valve 120c, the seventh valve 120g, and the parallel arrangement of the eleventh valve 120k and the fourth flow restrictor 121 d.

In the lifting apparatus 100, the first, second, third, fourth and fifth fluid lines 140a-140e are filled with fluid which is movable by the pumps 130a-130d towards the rams 110a-110d to transfer force to the rams 110a-110d to cause the rams 110a-110d to move, thereby to lift equipment engaged with the rams 110a-110d. When the pumps 130a-130d are not operating, the fluid in the fluid lines 140a-140e is movable towards the pumps 130a-130d by the weight of the rams 110a-110d (i.e. by the rams 110a-110d lowering under the force of gravity). The fluid may be a liquid (e.g. water or oil), in which case the lifting apparatus 100 is a hydraulic lifting apparatus, or a gas (e.g. air), in which case the lifting apparatus 100 is a pneumatic lifting apparatus.

Each of the rams 110a-110d is configured to engage with equipment such that, when that ram 110a-110d is caused to move, it applies a lifting force to the equipment with which it is engaged. For example, the rams 110a-110d may be configured to engage with equipment such that the equipment partially or wholly rests on the rams 110a-110d.

Each of the valves 120a-120k is switchable between an open state in which it permits the flow of fluid therethrough and a closed state in which it opposes or prevents the flow of fluid therethrough. Thus, the valves 120a-120k are configured to control the flow of fluid between the rams 110a-110d and the pumps 130a-130d. Each of the eighth, ninth, tenth and eleventh valves 120h- 120k is a bypass valve which, when open, enables a respective one of the flow restrictors 121 a-121 d to be bypassed. Each of the first, second, third, eighth, ninth, tenth and eleventh valves 120a, 120b, 120c, 120h, 120i, 120j, 120k may be any appropriate type of valve, for example a quarter turn shut-off valve. In this embodiment, each of the fourth, fifth, sixth and seventh valves 120d, 120e, 120f, 120g is a solenoid valve. Each of the valves 121 a-121 k described above may be a manually operated valve or an electronically controlled valve controlled by an electronic controller.

Each of the flow restrictors 121 a-121 d is configured to restrict the flow rate of fluid. In this embodiment, each of the first, second, third and fourth flow restrictors 121 a-121 d is a restricting orifice (e.g. a section of pipe with a smaller diameter compared to an "unrestricted" section of pipe).

Each of the pumps 130a-130d is configured to pump fluid which resides in the fluid lines 140a-140e towards one or more of the rams 110a-110d. Each pump 130a-130d comprises a respective fluid reservoir (not shown) from which fluid can be pumped into the fluid lines 140-140e by that pump, thereby to cause movement of the fluid in the fluid lines 140a-140e towards one or more of the rams 110a-110d. Each pump 130a-130d also comprises a respective return valve (not shown) via which fluid can flow back into that pump's fluid reservoir from the fluid lines 140a-140d when that pump is off (i.e. not operating). Each of the pumps 130a-130d may be a manually operated pump or an electronically controlled pump controlled by an electronic controller.

Each of the pressure sensors 150a-150d is configured to sense the pressure of fluid reaching a respective one of the rams 110a-110d. More specifically, the first pressure sensor 150a is configured to sense the pressure of fluid at a point on the first fluid line 140a between the first ram 110a and the fourth valve 120d, which is the same as the pressure of fluid reaching the first ram 110a. The second pressure sensor 150b is configured to sense the pressure of fluid at a point on the second fluid line 140b between the second ram 110b and the fifth valve 120e, which is the same as the pressure of fluid reaching the second ram 110b. The third pressure sensor 150c is configured to sense the pressure of fluid at a point on the third fluid line 140c between the third ram 110c and the sixth valve 120f, which is the same as the pressure of fluid reaching the third ram 110c. The fourth pressure sensor 150d is configured to sense the pressure of fluid at a point on the fourth fluid line 140d between the fourth ram 110d and the seventh valve 120g, which is the same as the pressure of fluid reaching the fourth ram 110d.

The lifting apparatus 100 described above is operable in each of a plurality of different modes. The lifting apparatus 100 can be switched between these different modes by reconfiguring the valves (i.e. changing which valves are open and which valves are closed) and/or reconfiguring the pumps (changing which pumps are on and which pumps are off). Five different modes in which the lifting apparatus 100 can be operated will now be described.

In a first mode (a so-called "equal pressure mode"): i) the first valve

120a, second valve 120b, third valve 120c, fourth valve 120d and eighth valve 120h are open, ii) the fifth valve 120e, sixth valve 120f, seventh valve 120g, ninth valve 120i, tenth valve 120j and eleventh valve 120k are closed, iii) the return valves of first, second, third and fourth pumps 130a-130d are closed, iv) the first pump 130a is on, and v) the second, third and fourth pumps 130b-130d are off.

In the first mode, since the second, third and fourth pumps 130b-130d are off and the fifth, sixth, seventh, ninth, tenth and eleventh valves 120e, 120f, 120g, 120i, 120j 120k are closed, only the first pump 130a operates to pump fluid towards the rams 110a-110d. In particular, the first pump 130a operates to pump fluid towards each of the first, second, third and fourth rams 110a-110d simultaneously. In more detail, fluid between the first ram 110a and the first pump 130a is pumped by the first pump 130a towards the first ram 110a via the fourth valve 120d and eighth valve 120h. Also, fluid between the second ram 110b and the first pump 130a is pumped by the first pump 130a towards the second ram 110b via the first valve 120a, fourth valve 120d and eighth valve 120h. Also, fluid between the third ram 110c and the first pump 130a is pumped by the first pump 130a towards the third ram 110c via the first valve 120a, second valve 120b, fourth valve 120d and eighth valve 120h. Also, fluid between the fourth ram 110d and the first pump 130a is pumped by the first pump 130a towards the fourth ram 110d via the first valve 120a, second valve 120b, third valve 120c, fourth valve 120d and eighth valve 120h.

In the first mode, the fluid at each of the first, second, third and fourth rams 110a-110d is at substantially the same pressure as the fluid at each of other rams. This is because, in this mode, the configuration of the valves described above means that each of the rams 110a-110d is in fluid communication with each of the other rams (i.e. the rams 110a-110d are not fluidly isolated from each other). Thus, in the first mode, each of the rams 110a- 110d applies substantially the same lifting pressure to equipment being lifted as each of the other rams.

In a second mode (a so-called "equal displacement mode"): i) the fourth valve 120d, fifth valve 120e, sixth valve 120f, seventh valve 120g, eighth valve 120h, ninth valve 120i, tenth valve 120j and eleventh valve 120k are open, ii) the first valve 120a, second valve 120b and third valve 120c are closed, iii) the return valves of first, second, third and fourth pumps 130a-130d are closed, iv) the first, second, third and fourth pumps 130a-130d are on.

In the second mode, each of the pumps 130a-130d operates to pump fluid towards a respective one of the rams 110a-110d. More specifically, fluid between the first ram 110a and the first pump 130a is pumped by the first pump 130a towards the first ram 110a via the fourth valve 120d and the eighth valve 120h. Also, fluid between the second ram 110b and the second pump 130b is pumped by the second pump 130b towards the second ram 110b via the fifth valve 120e and the ninth valve 120i. Also, fluid between the third ram 110c and the third pump 130c is pumped by the third pump 130c towards the third ram 110c via the sixth valve 120f and the tenth valve 120j. Also, fluid between the fourth ram 110d and the fourth pump 130d is pumped by the fourth pump 130d towards the fourth ram 110d via the seventh valve 120g and eleventh valve 120k. In this mode, each pump 130a-130d operates simultaneously to each of the other pumps so that the pumps 130a-130d all pump in unison.

In the second mode, since the first, second and third valves 120a, 120b, 120c are closed, each of the rams 110a-110d is fluidly isolated from each of the other rams 110a-110d. Thus, in this mode, the first pump 130a pumps fluid towards the first ram 110a without pumping fluid towards the second, third and fourth rams 110b, 110c, 110d. Also, the second pump 130b pumps fluid towards the second ram 110b without pumping fluid towards the first, third and fourth rams 110a, 110c, 110d. Also, the third pump 130c pumps fluid towards the third ram 110c without pumping fluid towards the first, second, and fourth rams 110a, 110b, 110d. Also, the fourth ram 130d pumps fluid towards the fourth ram 110d without pumping fluid towards the first, second and third rams 110a, 110b, 110c. In the second mode, the fluid reaching each of the first, second, third and fourth rams 110a-110d is not necessarily at the same pressure as the fluid reaching each of other rams, due to the fluid isolation described above. This means that, in the second mode, each of the rams 110a-110d is able to apply a different lifting pressure to equipment being lifted. The ability to apply different lifting pressures enables the rams 110a-110d to be operated so that each ram 110a-110d causes the same lifting displacement to equipment being lifted as each of the other rams. In other words, in the second mode, the rams 110a- 110d can be operated to lift equipment by the same amount as each other.

In a third mode (a so-called "hold mode"): i) the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh valves 120a-120k are closed, ii) the return valves of first, second, third and fourth pumps 130a-130d are closed, and iii) the first, second, third and fourth pumps 130a-130d are off.

In the third mode, since all of the valves of the lifting apparatus 100 are closed, fluid between the rams 110a-110d and the pumps 130a-130d is prevented from flowing towards or away from the rams 110a-110d. This means that, in this mode, there is no movement of the rams 110a-110d (i.e. no lifting or lowering) and thus any equipment engaged by the rams 110a-110d is not moved by the rams 110-110d (e.g. equipment resting on the rams 110a-110d remains held in place).

In a fourth mode (a so-called "prepare to lower mode"): i) the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh valves 120a-120k are closed, ii) the return valves of first, second, third and fourth pumps 130a-130d are open, and iii) the first, second, third and fourth pumps 130a-130d are off.

In the fourth mode, only the return valves of the pumps 130a-130d are open to prepare for the lowering of the rams 110a-110d. This ensures the return valves are ready to allow fluid to return to the fluid reservoirs of the pumps 130a-130d during subsequent lowering of the rams 110a-110d.

In a fifth mode (a so-called "lower mode"): i) the fourth valve 120d, fifth valve 120e, sixth valve 120f and seventh valve 120g are open, ii) the first valve 120a, second valve 120b, third valve 120c, eighth valve 120h, ninth valve 120i, tenth valve 120j and eleventh valve 120k are closed, iii) the return valves of first, second, third and fourth pumps 130a-130d are open, and iv) the first, second, third and fourth pumps 130a-130d are off.

In the fifth mode, since the return valves and the fourth, fifth, sixth and seventh valves 120d, 120e, 120f, 120g are open, and the first, second, third, eighth, ninth, tenth and eleventh valves 120a, 120b, 120c, 120h, 120i, 120j, 210k are closed, fluid in the fluid lines 140a-140d can flow back towards the fluid reservoirs of the pumps 130a-130d via said open valves 120d, 120e, 120f, 120g and the flow restrictors 121 a-121 d. More specifically, fluid between the first ram 110a and the first pump 130a can flow back towards the fluid reservoir of the first pump 130a via the fourth valve 120d, the first flow restrictor 121 a and the first return valve. Fluid between the second ram 110b and the second pump 130b can flow back towards the fluid reservoir of the second pump 130b via the fifth valve 120e, the second flow restrictor 121 b and the second return valve. Fluid between the third ram 110c and the third pump 130c can flow back towards the fluid reservoir of the third pump 130c via the sixth valve 120f, the third flow restrictor 121c and the third return valve. Fluid between the fourth ram 110d and the fourth pump 130d can flow back towards the fluid reservoir of the fourth pump 130d via the seventh valve 120g, the fourth flow restrictor 121 d and the fourth return valve.

In the fifth mode, movement of the fluid back towards the fluid reservoirs of the pumps 130a-130d is caused by the rams 110a-110d lowering under gravity to return to their original position, which pushes the fluid in the fluid lines 140a-140d towards the fluid reservoirs. The flow of the liquid via the flow restrictors 121 a-121 d in this mode tends to enable the lowering of the rams 110a-110d to take place in a more controlled and stable manner, which tends to reduce the likelihood of equipment being damaged during lowering.

In the fifth mode, the fourth, fifth, sixth and seventh valves 120d, 120e, 120f, 120g may be continually open (as described above) or may be opened and closed periodically. In the latter case, the fourth, fifth, sixth and seventh valves 120d, 120e, 120f, 120g valves may be periodically opened and closed by an electronic controller comprising a timing circuit. Said electronic controller may be configured to periodically open and close the fourth, fifth, sixth and seventh valves based on a periodic timing performed by the timing circuit. For example, the electronic controller may simultaneously open said valves and keep them open for a first period of time (e.g. 0.1 s), then simultaneously close said valves and keep them closed for a second period of time (e.g. 0.1 s), then simultaneously open said valves and keep them open for the first period of time, then simultaneously close said valves and keep them closed for the second period of time, and so on, until the lifting apparatus is stopped from operating in the fifth mode. Such periodic opening and closing of these valves 120d-120g tends to advantageously enable the rams 110a-110d to lower in a more controlled way, since it tends to provide more time for a user to monitor the lowering and to stop the lowering if desired.

Figure 2 is a flowchart showing various steps of a method of operating the lifting apparatus 100 described above with reference to Figure 1.

At step s2, the lifting apparatus 100 is placed by a user at a location where lifting is to be performed. In particular, the lifting apparatus 100 is placed such that the rams 110a-110d are located below equipment which is to be lifted. For example, lifting apparatus 100 may be placed such that the rams 110a- 110d are located below a vacuum pumping or abatement apparatus in a vacuum pumping and/or abatement system.

At step s4, the lifting apparatus 100 is operated by the user in the first mode (i.e. the "equal pressure mode") to move each of the rams 110a-110d into engagement with the equipment such that the rams 110a-110d at least partially support the weight of the equipment without causing lifting of the equipment. This may also be referred to as moving the rams 110a-110d into "intimate contact" with the equipment. At this step, each ram 110a-110d is able to move by a different amount which means that each ram 110a-110d is able to move into intimate contact with a different part of the equipment, even if the different parts of the equipment are at different heights above the rams 110a-110d to each other. The point at which the rams 110a-110d have all moved into intimate contact with the equipment may be determined by a user observing that the pressure measured by each of the first, second, third and fourth pressure sensors 150a-150d is above a predetermined threshold pressure. At step s6, the lifting apparatus 100 is operated by the user in the second mode (i.e. the "equal displacement mode") to cause lifting of the equipment. During this lifting, the pumps 130a-130d are operated simultaneously by the user (e.g. manually operated via a common handle) such that each ram 110a- 110d lifts the equipment by the same amount (i.e. causes the same lifting displacement). For example, during lifting, the user may monitor the amount of displacement caused by each of the rams (e.g. by eye or by way of a monitoring device) and operate the pumps 130a-130d so that each of the rams 110a-110d lifts by the same amount. At this step, the lifting is continued until the equipment reaches a predetermined desired height.

At step s8, the lifting apparatus 100 is operated in the third mode (i.e. the "hold mode") to hold the equipment in place without lifting or lowering the equipment. The equipment may then be removed from the lifting apparatus (e.g. to be installed or used at the predetermined desired height). Alternatively, the equipment may be kept on the lifting apparatus 100 and operations (e.g. inspection, maintenance, repair) may be performed on the equipment while it is on the lifting apparatus 100 at the predetermined desired height.

At step s10, the lifting apparatus 100 is operated by the user in the fourth mode (i.e. the "prepare to lower mode") to prepare for lowering of the rams 110a-110d.

At step s12, the lifting apparatus 100 is operated by the user in the fifth mode (i.e. the "lower mode") to lower the rams 110a-110d to their original position. Switching to the fifth mode from the fourth mode comprises simultaneously opening, by the user, the fourth valve 120d, fifth valve 120e, sixth valve 120f and seventh valve 120g. This simultaneous opening causes all of the rams 110a-110d to start lowering the same time as each other, which tends to result in uniform lowering of the rams 110a-110d. The fourth, fifth, sixth and seventh valves 120d-120g are also simultaneously closable by the user. In this embodiment, the fourth, fifth, sixth and seventh valves 120d, 120e, 120f, 120g being solenoid valves tends to facilitate the simultaneous opening of these valves by the user, since multiple solenoid valves can easily be opened simultaneously with a common switch (e.g. a common normally-open switch) operated by the user. At step s14, the lifting apparatus 100 is removed from the location that it was placed at step s2 (e.g. the lifting apparatus 100 may be disengaged from the equipment). The lifting apparatus 100 is then ready for use again to lift other equipment at a different (or the same) location.

It will be appreciated that some of the process steps depicted in the flowchart of Figure 2 and described above may be omitted or performed in differing order to that presented below and shown in Figure 2. Furthermore, although the process steps have, for convenience and ease of understanding, been depicted as discrete temporally-sequential steps, nevertheless some of the process steps may in fact be performed simultaneously or at least overlapping to some extent temporally.

Figure 3 is a schematic illustration (not to scale) showing a perspective view of an embodiment of a ram 200 which may be used as any of the first, second, third and fourth rams 110a-110d described above.

Figure 4 is a schematic illustration (not to scale) showing a side view of the ram 200 illustrated in Figure 3.

Referring to Figures 3 and 4, the ram 200 comprises a body 210, a first piston 220a and a second piston 220b. The body 210 comprises a first bore and a second bore therein. The first piston 220a is disposed within the first bore at a first end of the body 210. The first piston 220a is coaxially aligned with the first bore. The second piston 220b is disposed within the second bore at a second end of the body 210, the second end being opposite to the first end. The second piston 220b is coaxially aligned with the second bore. The first bore comprises an opening in a top surface 212 of the body 210, through which the first piston 220a is movable. The second bore comprises an opening in a bottom surface

214 of the body 210, through which the second piston 220b is movable. The longitudinal axes of the first piston 220a and the second piston 220a are substantially parallel with each other. In this embodiment, the body 210 of the ram 200 has an I-shaped transverse cross-section. The first piston 220a is movable within the first bore to extend at least a portion of the first piston 220a out of the opening in the top surface 212 of the body 210. Similarly, the second piston 220b is movable within the second bore to extend at least a portion of the second piston 220b out of the opening in the bottom surface 214 of the body 210. Thus, the first piston 220a and the second piston 220b are configured to move away from opposite surfaces of the body 210 in opposite, substantially parallel directions. This movement of the first and second pistons 220a, 220b may be caused by fluid which is pumped into the first and second bores via one or more inlets (not shown) of the bores by one or more of the pumps 130a-130d described above. The movement of at least a portion of the first piston 220a out of the first bore enables the first piston 220a to move into engagement with (and push against) equipment placed on the top surface 212 of the body 210. The movement of the second piston 220b out of the second bore enables the second piston 220b to move into engagement with and push against a rest surface (e.g. a floor) on which the bottom surface 214 of the body 210 is placed. Thus, the ram 200 is able to lift equipment by moving the first and second pistons 220a, 220b in opposite directions to each other, which means that the ram tends to able to lift equipment by approximately twice the distance (i.e. has twice the stroke distance) compared to the same ram but with only one piston.

The use of two pistons 220a, 220b at opposite ends of the ram body 210 which move in opposite directions, as described above, tends to mean that there is a net torque generated on the ram 200 by the movement of the pistons 220a, 220b. In order to counteract this, more than one of the rams 200 may be mechanically coupled together to resist said torque, as will be described below.

Figure 5 is a schematic illustration (not to scale) showing a top-down view of a plurality of the rams 200 mechanically coupled together.

In this embodiment, the plurality of rams 200 comprises four rams 200, each of the four rams being in accordance with the ram 200 described above with reference to Figures 3 and 4. The four rams 200 are mechanically coupled to each other via a frame structure 300. This mechanical coupling fixes the rams 200 to each other so that movement of the rams 200 relative to each other is opposed or prevented. Thus, in this embodiment, the torque generated by the opposite movement of the pistons 220a, 200b of each of the rams 200 is opposed or prevented by the mechanical coupling of the rams 200 to each other via the frame 300. This tends to stabilize the rams 200 when they are lifting or lowering.

In this embodiment, the four rams 200 and the frame 300 are mechanically coupled to each other in a rectangular arrangement with each of the four rams 200 located at or proximate to a corner of the rectangle. However, it will be appreciated that a different number of rams 200 (e.g. three, five, six etc.) and/or a differently shaped arrangement (e.g. triangular, pentagonal, hexagonal, circular) may be used instead. Preferably, the torque generated by the rams 200 is counteracted by mechanically coupling the rams 200 together. In this embodiment, the I-shaped transverse cross-section of the body

210 of each of the rams 200 tends to enable each of the rams 200 to hook onto the frame structure 300, which tends to facilitate the mechanical coupling of the rams 200 to the frame structure 300.

The lifting apparatus 100 described above may have the following dimensions: 100cm long, 50cm wide and 6cm high. The ram 200 described above may have the following dimensions: 12cm long, 6cm wide and 6 cm high. These dimensions may be particularly suitable for use with vacuum pumping and/or abatement systems.

Thus, a lifting apparatus and method of operating said lifting apparatus is provided.

Advantageously, above-described lifting apparatus tends to allow easy switching between the modes (i.e. by reconfiguring the valves and/or pumps), which tends to avoid the use of further equipment or the reconnection of parts.

Advantageously, the above-described ability of the lifting apparatus to operate in the first and second modes tends to enable the lifting apparatus to lift equipment in an even manner without causing undesirable tilting of said equipment. This tends to be particularly useful when lifting equipment with an offset centre of gravity.

Advantageously, the above-described use of only one pump to pump fluid in the first mode tends to reduce wear and tear on the other pumps which are not used. Advantageously, the structure of the ram described above with reference to Figures 3 and 4 tends to allow the height of the ram to be kept relatively small for the amount that the ram can lift equipment by. This tends to be particularly useful in vacuum pumping and/or abatement systems where the amount of space available beneath equipment to place rams may be limited.

In the above embodiments, the lifting apparatus comprises four rams, four pumps, and the corresponding number of valves and flow restrictors described above with reference to Figure 1. Flowever, in other embodiments, the lifting apparatus comprises a different plural number of rams, pumps, valves and/or flow restrictors. For example, in some embodiments, the lifting apparatus 100 is the same as the one described above with reference to Figure 1 , except that the third ram, third pump, fourth ram, fourth pump, second valve, third valve, sixth valve, seventh valve, tenth valve, eleventh valve, third flow restrictor, and second flow restrictor are all omitted.

In some embodiments, one or more of the parallel arrangements of a bypass valve and flow restrictor are omitted. For example, in some embodiments, the eighth valve, ninth valve, tenth valve, eleventh valve, first flow restrictor, second flow restrictor, third flow restrictor and fourth flow restrictor are all omitted.

In the above embodiments, the first, second, third and fourth flow restrictors are restricting orifices. Flowever, in other embodiments, a different type of flow restrictor is used for or more of these flow restrictors.

In the above embodiments, the fourth, fifth, sixth and seventh valves are solenoid valves. Flowever, in other embodiments, a different type of valve is used for one or more of these valves.

In the above embodiments, the pumps each have a respective fluid reservoir. Flowever, in other embodiments the pumps all share a common fluid reservoir.

In the above embodiments, in the first mode, only the first pump operates to pump fluid. Flowever, in other embodiments, in the first mode, one or more of the other pumps also operate to pump fluid instead of or in addition to the first pump. In the above embodiments, the return valves of first, second, third and fourth pumps are closed in the first mode. However, in other embodiments, one or more of these valves are open in the first mode (e.g. the return valves may all be open in the first mode).

In the above embodiments, the first valve, second valve, third valve are closed in the fifth mode. However, in other embodiments, one or more of these valves are open in the fifth mode (e.g. the first, second and third valves may all be open in the fifth mode).

REFERENCE NUMERAL KEY 100: lifting apparatus

110a: first ram

110b: second ram

110c: third ram

110d: fourth ram

120a: first valve

120b: second valve

120c: third valve

120d: fourth valve

120e: fifth valve

120f: sixth valve

120g: seventh valve

120h: eighth valve

120i: ninth valve

120j: tenth valve

120k: eleventh valve

121 a: first flow restrictor 121 b: second flow restrictor 121 c: third flow restrictor

121 d: fourth flow restrictor 130a: first pump

130b: second pump

130c: third pump

130d: fourth pump

140a: first fluid line 140b: second fluid line

140c: third fluid line

140d: fourth fluid line

140e: fifth fluid line

150a: first pressure sensor

150b: second pressure sensor 150c: third pressure sensor 150d: fourth pressure sensor 200: ram

210: body

212: top surface

214: bottom surface

220a: first piston

220b: second piston

300: frame structure

Claims

1. A lifting apparatus for lifting vacuum pumping and/or abatement equipment, the lifting apparatus comprising:

a plurality of rams for engaging with equipment;

a plurality of pumps for pumping fluid to the plurality of rams to cause the plurality of rams to move equipment engaged with the plurality of rams; and a plurality of valves for controlling the flow of fluid between the plurality of rams and the plurality of pumps, wherein the plurality of rams are connected to the plurality of pumps via the plurality of valves,

wherein the lifting apparatus is operable in a first mode in which the plurality of valves are configured such that each of the plurality of rams is in fluid communication with each other ram, and

wherein the lifting apparatus is operable in a second mode in which the plurality of valves are configured such that each of the plurality of rams is fluidly isolated from each other ram.

2. The lifting apparatus of claim 1 , wherein the plurality of valves are operable to switch the lifting apparatus between operating in the first mode and operating the second mode.

3. The lifting apparatus of claim 1 or claim 2, wherein the lifting apparatus is operable in a third mode in which the plurality of pumps are off and the plurality of rams move to push fluid towards the plurality of pumps via the plurality of valves.

4. The lifting apparatus of any of claims 1 to 3, wherein:

the lifting apparatus comprises a first fluid line, a second fluid line and a third fluid line,

the plurality of rams comprise a first ram and a second ram,

the plurality of pumps comprise a first pump and a second pump, the plurality of valves comprise a first valve, a second valve and a third valve,

the first ram is connected to the first pump by the first fluid line, the second ram is connected to the second pump by the second fluid line,

the first fluid line is connected to the second fluid line by the third fluid line, and

the first valve is disposed on the first fluid line between the first ram and the first pump, the second valve is disposed on the second fluid line between the second ram and the second pump, and the third valve is disposed on the third fluid line.

5. The lifting apparatus of claim 4, wherein:

in the first mode, the first pump simultaneously pumps fluid towards both the first ram and the second ram.

6. The lifting apparatus of claim 5 or claim 4, wherein:

in the second mode, the first pump pumps fluid towards the first ram without pumping fluid towards the second ram and, simultaneously, the second pump pumps fluid towards the second ram without pumping fluid towards the first ram.

7. The lifting apparatus of any of claims 4 to 6 when dependent on claim 3, wherein the first and second valves are simultaneously openable to switch the lifting apparatus from operating in the second mode to operating in the third mode.

8. The lifting apparatus of any of claims 4 to 7, wherein:

when the third valve is open, the first ram in is fluid communication with the second ram, and when the third valve is closed, the first ram is fluidly isolated from the second ram.

9. The lifting apparatus of any of claims 4 to 8 when dependent on claim 3, wherein the lifting apparatus further comprises a first flow restrictor disposed on the first fluid line and a second flow restrictor disposed on the second fluid line, wherein, in the third mode, the first ram moves to push fluid towards the first pump via the first flow restrictor and the second ram moves to push fluid towards the second pump via the second flow restrictor.

10. The lifting apparatus of claim 9, wherein the lifting apparatus further comprises a first bypass valve connected in parallel with the first flow restrictor and a second bypass valve connected in parallel with the second flow restrictor.

11. A method of operating a lifting apparatus for lifting vacuum pumping and/or abatement equipment, the lifting apparatus comprising a plurality of rams for engaging with equipment, a plurality of pumps for pumping fluid to the plurality of rams to cause the plurality of rams to move equipment engaged with the plurality of rams, a plurality of valves for controlling the flow of fluid between the plurality of rams and the plurality of pumps, wherein the plurality of rams are connected to the plurality of pumps via the plurality of valves,

the method comprising:

operating the lifting apparatus in a first mode in which the plurality of valves are configured such that each of the plurality of rams is in fluid

communication with each other ram; and

operating the lifting apparatus in a second mode in which the plurality of valves are configured such that each of the plurality of rams is fluidly isolated from each other ram.

12. The method of claim 11 , further comprising:

operating the plurality of valves to switch the lifting apparatus between operating in the first mode and operating in the second mode.

13. The method of claim 11 or claim 12, further comprising:

operating the lifting apparatus in a third mode in which the plurality of pumps are off and the plurality of rams move to push fluid towards the plurality of pumps via the plurality of valves.

14. A ram for a lifting apparatus for lifting vacuum pumping and/or abatement system equipment, the ram comprising:

a body comprising a first bore and a second bore;

a first piston disposed within the first bore, wherein at least a portion of the first piston is movable out of the first bore in a first direction; and

a second piston disposed within the second bore, wherein at least a portion of the second piston is movable out of the second bore in a second direction opposite to the first direction.

15. The lifting apparatus of any of claims 1 to 10, wherein each of the plurality of rams is a ram in accordance with claim 14, and wherein the plurality of rams are mechanically coupled together by a frame structure.