# US 2018/0320673 A1 · Solenoid Pump Driver

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- Number: US 2018/0320673 A1
- Document ID: US20180320673A1
- Status: Published application
- Kind: A1
- Application number: 15/771,494
- Filed: 2016-10-31
- Published: 2018-11-08
- Earliest claimed: 2015-10-30
- Assignees: Aspen Pumps Limited
- Applicants: Aspen Pumps Limited
- Inventors: Gary Haffenden
- Web page: https://patentgrep.com/patent/US20180320673A1

## CPC

- F04B 17/046: {the fluid flowing through the moving part of the motor}
- F04B 17/04: using solenoids
- F04B 35/045: {using solenoids}
- F04B 49/065: {and making use of computers}
- F04B 2203/0402: Voltage
- F04B 2203/0404: Frequency of the electric current
- 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)

## Abstract

A method of driving a solenoid pump of the type comprising a metal shuttle urged by a solenoid against a spring with the spring providing the force for the pumping stroke of the shuttle is disclosed. The method comprises applying a periodic driving voltage to the solenoid. Each period of the driving voltage comprises a first portion during which the driving voltage increases from a minimum voltage to a maximum voltage to compress the spring, a second portion during which the driving voltage decreases from the maximum voltage to the minimum voltage to release the spring, and a third portion during which the driving voltage is maintained at the minimum voltage. The duration of the second portion is substantially less than the duration of the first portion and may be substantially instantaneous. The driving voltage increases from the minimum voltage to the maximum voltage substantially linearly during the first portion, such that the driving voltage has a sawtooth waveform.

## Claims

### Claim 1

A method of driving a solenoid pump of the type comprising a metal shuttle urged by a solenoid against a spring with the spring providing the force for a pumping stroke of the shuttle, the method comprising applying a periodic driving voltage to the solenoid,
wherein each period of the driving voltage comprises a first portion during which the driving voltage increases from a minimum voltage to a maximum voltage to compress the spring, a second portion during which the driving voltage decreases from the maximum voltage to the minimum voltage to release the spring, and a third portion during which the driving voltage is maintained at the minimum voltage, wherein the duration of the second portion is substantially less than the duration of the first portion.

### Claim 2 (depends on 1)

A method as claimed in claim 1, wherein the driving voltage decreases from the maximum voltage to the minimum voltage substantially instantaneously during the second portion.

### Claim 3 (depends on 1)

A method as claimed in claim 1, wherein the driving voltage increases from the minimum voltage to the maximum voltage substantially linearly during the first portion.

### Claim 4 (depends on 1)

A method as claimed in claim 1, wherein the driving voltage has a sawtooth waveform.

### Claim 5 (depends on 1)

A method as claimed in claim 1 further comprising controlling the duration of the third portion to provide a required flow rate through the pump.

### Claim 6

A method as claimed in claim further comprising controlling the maximum voltage to provide a required flow rate through the pump.

### Claim 7 (depends on 1)

A method as claimed in claim 1, wherein the frequency of the driving voltage is different to the frequency of a supply voltage providing electrical power for the driving voltage.

### Claim 8 (depends on 1)

A method as claimed in claim 1 further comprising controlling the frequency of the driving voltage to provide a required flow rate through the pump.

### Claim 9 (depends on 1)

A method as claimed in claim 1, wherein the minimum voltage is zero volts.

### Claim 10 (depends on 1)

A driver circuit for a solenoid pump, the driver circuit configured to generate a driving voltage in accordance with the method of claim 1.

### Claim 11 (depends on 11)

A solenoid pump in combination with the driver circuit of claim 11.