# US 8,540,498 B2 · Compressor-expander set critical speed avoidance

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,540,498 B2
- Document ID: US8540498B2
- Status: Granted
- Kind: B2
- Application number: 13/743,418
- Filed: 2013-01-17
- Published: 2013-05-23
- Granted: 2013-09-24
- Earliest claimed: 2008-03-13
- Assignees: Compressor Controls Corporation
- Applicants: Compressor Controls Corporation
- Inventors: Saul Mirsky; Wayne Jacobson; David J. Hoogerwerf
- Web page: https://patentgrep.com/patent/US8540498B2

## CPC

- F25B 31/00: Compressor arrangements
- F01D 21/02: Shutting-down responsive to overspeed
- F02C 9/18: by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)}
- F04B 49/02: Stopping, starting, unloading or idling control
- F04D 25/04: the pump being fluid-driven {(pumps driven by exhaust gases F02B37/00, F02B39/00; turbochargers F02C6/12)}
- F04D 27/0261: {by varying driving speed}
- F25B 11/02: as expanders (F25B9/06 takes precedence)
- F25J 1/0022: {Hydrocarbons, e.g. natural gas}
- F25J 1/005: {by expansion of a gaseous refrigerant stream with extraction of work}
- F25J 1/0052: {by vaporising a liquid refrigerant stream}
- F25J 1/0072: {Nitrogen}
- F25J 1/0218: {with one or more SCR cycles, e.g. with a C3 pre-cooling cycle}
- F25J 1/0265: {comprising cores associated exclusively with the cooling of a refrigerant stream, e.g. for auto-refrigeration or economizer}
- F25J 1/0271: {Inter-connecting multiple cold equipments within or downstream of the cold box}
- F25J 1/0272: {Multiple identical heat exchangers in parallel}
- F25J 1/0283: {Gas turbine as the prime mechanical driver}
- F25J 1/0288: {using work extraction by mechanical coupling of compression and expansion of the refrigerant, so-called companders}
- F25J 1/0294: {Multiple compressor casings/strings in parallel, e.g. split arrangement}
- F25J 1/0298: {Safety aspects and control of the refrigerant compression system, e.g. anti-surge control}
- F05D 2270/021: to prevent overspeed
- F25J 2240/04: Multiple expansion turbines in parallel
- F25J 2270/16: with mutliple gas expansion loops of the same refrigerant
- F25J 2290/34: Details about subcooling of liquids
- Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F25J: LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)}
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A control method and apparatus for critical rotational speed avoidance in a compressor-expander set in a gas refrigeration system. By varying an opening of an antisurge or recycle valve, a shaft power used by the compressor in the compressor-expander set may be varied, thereby varying the rotational speed of the compressor-expander set to move it away from its critical speed zone. Additionally, a feedforward signal may be provided by a compressor-expander set control system to cause an antisurge valve for a recycle compressor to open upon a trip or shutdown of one compressor-expander set.

## Claims

### Claim 1

A method of surge avoidance for a recycle compressor within a gas refrigeration system, the gas refrigeration system comprising a compressor-expander set in fluid communication and connected in series with the recycle compressor, a compressor-expander set control system, a recycle compressor control system, and a recycle compressor antisurge valve, the method comprising:
(a) causing the compressor-expander set to shutdown;
(b) sending a feedforward signal from the compressor-expander control system to the recycle compressor control system indicating a shutdown of the compressor-expander set; and
(c) increasing an opening of the recycle compressor antisurge valve upon reception of the feedforward signal by the recycle compressor control system.

### Claim 2 (depends on 1)

The method of claim 1 wherein increasing the opening of the recycle compressor antisurge valve comprises increasing the opening of the recycle compressor antisurge valve a predetermined amount.

### Claim 3

An apparatus for surge avoidance for a recycle compressor comprising:
(a) a gas refrigeration system with which the recycle compressor is in fluid communication;
(b) a compressor-expander set in fluid communication and connected in series with the recycle compressor;
(c) a compressor-expander set control system;
(d) a recycle compressor control system;
(e) a recycle compressor antisurge valve;
(f) a shutdown signal from the compressor-expander set to signal the compressor-expander set to shutdown;
(g) a feedforward signal from the compressor-expander control system to the recycle compressor control system indicating a shutdown of the compressor-expander set; and
(h) a signal from the recycle compressor's control system to signal an increase of opening of the recycle compressor antisurge valve upon reception of the feedforward signal by the recycle compressor control system.