# US 8,540,478 B2 · Multistage high-pressure pump

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- Number: US 8,540,478 B2
- Document ID: US8540478B2
- Status: Granted
- Kind: B2
- Application number: 12/523,773
- Filed: 2008-01-21
- Published: 2010-04-01
- Granted: 2013-09-24
- Earliest claimed: 2007-01-22
- Assignees: Ebara Corporation
- Applicants: Akio Teragaki
- Inventors: Akio Teragaki
- Web page: https://patentgrep.com/patent/US8540478B2

## CPC

- F16J 15/3404: {and characterised by parts or details relating to lubrication, cooling or venting of the seal}
- F04D 1/063: {of the vertically split casing type}
- F04D 7/06: the fluids being hot or corrosive, e.g. liquid metals
- F04D 29/108: {the sealing fluid being other than the working liquid or being the working liquid treated}
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)

## Abstract

A multistage high-pressure pump according to the present invention includes a rotational shaft (1), impellers (3) secured to the rotational shaft, a casing (2) configured to house the impellers therein, a mechanical seal (20), a seal chamber (25) that houses the mechanical seal therein, an oil reservoir (30) configured to store oil therein, an oil supply line (26) providing fluid communication between the oil reservoir (30) and the seal chamber (25), an oil pump (31) configured to pressurize the oil from the oil reservoir (30) and supply the oil to the seal chamber (25), a pressure retaining mechanism (32, 34, 35) configured to retain pressure of the oil in the seal chamber (25), and an oil outlet line (27) for discharging the oil from the seal chamber (25). The pressure of the oil in the seal chamber (25) is higher than pressure of the fluid.

## Claims

### Claim 1

A multistage high-pressure pump for pressurizing a fluid, comprising:
a rotational shaft;
impellers secured to said rotational shaft;
a casing configured to house said impellers therein;
a mechanical seal constituted by a first pair of rotary seal member and stationary seal member in sliding contact with each other and a second pair of rotary seal member and stationary seal member in sliding contact with each other;
a stuffing box secured to a side end of said casing and housing said mechanical seal therein;
a seal chamber surrounded by a periphery of said rotational shaft, said stuffing box, and said first and second pairs of rotary seal members and stationary seal members;
an oil reservoir configured to store oil therein;
an oil supply line providing a communication between said oil reservoir and said seal chamber;
an oil pump configured to pressurize the oil from said oil reservoir and supply the oil to said seal chamber, a gap being formed between said rotary seal member and said stationary seal member of each pair for discharging the oil from said chamber;
a pressure retaining mechanism configured to retain pressure of the oil in said seal chamber such that the pressure of the oil in said seal chamber is higher than pressure of the fluid; and
an oil outlet line for discharging the oil from said seal chamber, said oil outlet line being connected to said seal chamber at a site different from the gap.

### Claim 2 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein said pressure retaining mechanism includes:
a check valve provided on said oil supply line at a position between said oil pump and said seal chamber;
at least one accumulator located between said check valve and said seal chamber; and
a shut-off valve provided on said oil outlet line.

### Claim 3 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein said mechanical seal is in contact with the fluid.

### Claim 4 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein said rotary seal members of said first and second pairs are rotatable in unison with said rotational shaft, and said stationary seal members of said first and second pairs are secured to a stationary member.

### Claim 5 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein said seal chamber is located in said stuffing box which is secured to a side end of said casing.

### Claim 6 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein said oil outlet line is coupled to said oil reservoir.

### Claim 7 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein the oil, that has passed through the gaps between said rotary seal members and said stationary seal members, is expelled to an exterior of said pump through a drain.

### Claim 8 (depends on 1)

The multistage high-pressure pump according to claim 1, wherein said oil pump is configured to circulate the oil between said oil reservoir and said seal chamber.

### Claim 9 (depends on 2)

The multistage high-pressure pump according to claim 2, wherein said shut-off valve is configured to be closed in case of a power failure.