US-12624704-B2 - Air venting

US12624704B2US 12624704 B2US12624704 B2US 12624704B2US-12624704-B2

Abstract

The invention relates in a first aspect to method of venting air out of a closed fluid system comprising a number of inter connected pipes configured for flow of a fluid, a variable speed pump configured for controlling the volume flow of fluid in said fluid system and an air venting device configured to let air out from the fluid system, the method comprising operating said pump in at least three phases.

Inventors

Bjarne Dindler Rasmussen
Lars Sund MORTENSEN
Ole Bech-Lisberg
Mathias Skødt LARSEN

Assignees

GRUNDFOS HOLDING A/S

Dates

Publication Date: 20260512
Application Date: 20230918
Priority Date: 20220922

Claims (20)

1 . A method of venting air out of a closed fluid system, the closed fluid system including a number of inter connected pipes configured for flow of a fluid, a variable speed pump configured for controlling the volume flow of fluid in said fluid system by varying a rotational speed of the pump and an air venting device configured to let air out from the fluid system, the method comprising: operating said pump in at least three phases, wherein: in a first phase, said variable speed pump is operated by varying the rotational speed of the pump to provide a number of first flow pulses in said fluid system each having a pulse width being shorter than a first pulse width; in a second phase, during which air, if present in said fluid, is detected; and in a third phase, said variable speed pump is operated by varying the rotational speed of the pump to provide a number of third flow pulses in said fluid system each having a pulse width being longer than said first pulse width.
2 . A method according to claim 1 , wherein said variable speed pump in the second phase is operated to provide a non-pulsed flow in said fluid system during a time period being longer than said first pulse width.
3 . A method according to claim 2 , wherein the non-pulsed flow is a constant flow.
4 . A method according to claim 3 , wherein during operation of said pump in said second phase, further comprising: detecting a step up in the rotational speed of said variable speed pump and/or a step down in power consumption of said variable speed pump.
5 . A method according to claim 2 , wherein during operation of said pump in said second phase, further comprising: detecting a step up in the rotational speed of said variable speed pump and/or a step down in power consumption of said variable speed pump.
6 . A method according to claim 1 , wherein during operation of said pump in said second phase, further comprising: detecting a step up in the rotational speed of said variable speed pump and/or a step down in power consumption of said variable speed pump.
7 . A method according to claim 6 , wherein the method is computer implemented and includes a processor configured to control the rotational speed of said variable speed pump to carry out said first phase, said second phase, and said third phase.
8 . A method according to claim 1 , wherein the volume flow in one or more of said first flow pulses and wherein the volume flow in one or more of said third flow pulses increases from a first volume flow to a second volume flow and subsequently decreases the second volume flow to said first volume or to a third volume flow.
9 . A method according to claim 8 , wherein said first volume flow is a preselected minimum volume flow and said second volume flow is a preselected maximum volume flow.
10 . A method according to claim 8 , wherein a rate of change of volume flow during said increase is imposed by changing the rotational speed of the variable speed pump from the rotational speed providing said first volume flow to the rotational speed providing said second volume flow over a time period being larger than 1 ms.
11 . A method according to claim 10 , wherein said changing the rotational speed of the variable speed pump from the rotational speed providing said first volume flow to the rotational speed providing said second volume flow over a time period being smaller than 5 seconds.
12 . A method according to claim 8 , where one or more of said pulses comprises a time period with constant volume flow immediately after the volume flow has increased to said second volume flow.
13 . A method according to claim 8 , wherein an absolute value of a rate of change of volume flow during said decrease is imposed by changing the rotational speed of the pump from the rotational speed providing said second volume flow to the rotational speed providing said second volume flow or said third volume flow over a time period being larger than 1 ms.
14 . A method according to claim 1 , wherein the second phase is executed recursively for a number of times prior to executing said first and said third phase.
15 . A method according to claim 1 , wherein said first, second and third phases are executed in cycles, and wherein the execution of said cycles is stopped when a predefined criteria has been met.
16 . A closed fluid system comprising a number of inter connected pipes configured for flow of a fluid, a variable speed pump configured for controlling the volume flow of fluid in said fluid system and an air venting device configured to let air out from the fluid system, wherein said closed fluid system comprising a processor configured to carry out the method according to claim 1 .
17 . A method according to claim 1 , further comprising: a zero phase, during which the rotational speed of said variable speed pump is ramped-up and/or ramped-down in-between a maximum rotational speed and a minimum rotational speed during which the volume flow through said variable speed pump is recorded.
18 . A method according to claim 1 , wherein the method is computer implemented and includes a processor configured to control the rotational speed of said variable speed pump to carry out said first phase, said second phase, and said third phase.
19 . A method according claim 18 , wherein during operation of said pump in said second phase the processor is further configured to determine a step up in a rotational speed of said variable speed pump and/or a step down in power consumption of said variable speed pump, thereby detecting air present in the variable speed pump.
20 . A method according to claim 18 , wherein said processor is located within a housing of said pump.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a U.S. Nonprovisional Application of Danish Patent Application No. PA 2022 70461 filed on Sep. 22, 2022, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION The invention relates in a first aspect to method of venting air out of a closed fluid system comprising a number of inter connected pipes configured for flow of a fluid, a variable speed pump configured for controlling the volume flow of fluid in said fluid system and an air venting device configured to let air out from the fluid system, the method comprising operating said pump in at least three phases. BACKGROUND OF THE INVENTION Many heating and cooling systems utilizes a medium (a fluid) such as water for transport of heat. In such system the medium is circulated in pipes forming a distribution network distributing the medium to various heat exchanges such as radiators, floor heating pipes. In heating system the medium is heated by a heat source, such as a boiler, heat pump or solar panel. To effectively circulate the medium, such systems are equipped with one or more pump which circulate the medium. Quite often systems suffer from the drawback of air in the medium. Problems relating to air in such systems are numerous and may be one or more of irritating noise generating, lowering of a system's efficiency to transport heat (due to air having a lower heat capacity than water) and/or malfunction of the system in the sense that the air present prevents an effective circulation of the medium in at least some branches of the system. Air may enter into a system by different causes. For instance, when installing a system for the first time, there will, of course be air in the piping that needs to be removed. Further, during service of a system, the medium is often drained in at least a part system for a later refilling after service. Such operations also introduces air into the system. In addition, the medium when introduced often contains air which over time will be released from the water forming air pocket. In some situations, a system is pressurized to an above atmospheric pressure and although a system is constructed with great care with regards to being water tight, it is not uncommon that small amount of water is leaking e.g. at a fitting connecting pipes or connecting a sensor. Although this seldom is a larger issue as such, such leaks demands a top-up of water whereby air may be introduced via this top-up. In some instances, the system may even comprise an automatic top-up. In an addition, air may leak into a system e.g. through seals e.g. due to pressure fluctuations in the system. To avoid presence of air, systems are often equipped with an air-venting device allowing air to escape the system during filling and operation. While such air-venting device may at least potentially mitigate problems relating to the presence of air, it is quite often so that manually venting is needed e.g. at a radiator as the air-venting device and the layout of the system prevents air from leaving the system through the air-venting device. Needleless to say, manually venting is undesired as it often involves that a service technician to manually detect the presence of air and its location, and design a way to remove the water. While this can, of course, be carried out manually the process is often time and costs consuming and needs to await that the service technician is available, during which time the system is either not operating or at least operates in a less desired way. Thus, an improved manner of venting a system is desirable. OBJECT OF THE INVENTION It is an object of the invention to provide a more efficient method and device for venting air out of a fluid system. It is a further object of the present invention to provide an alternative to the prior art. SUMMARY OF THE INVENTION The invention relates in a first aspect to method of venting air out of a closed fluid system comprising a number of inter connected pipes configured for flow of a fluid, a variable speed pump configured for controlling the volume flow of fluid in said fluid system and an air venting device configured to let air out from the fluid system, the method comprising operating said pump in at least three phases, wherein in a first phase, said pump is operated to provide a number of first flow pulses in said fluid system each having a pulse width being shorter than a first pulse width,in a second phase, during which air, if present in said fluid, is detected, andin a third phase, said pump is operated to provide a number of third flow pulses in said fluid system each having a pulse width being longer than said first pulse width. Preferred embodiments of the invention provides inter alia the effect of providing an efficient venting air out of a closed fluid system, by utilizing the first and third phases. As will become apparent from the following detailed description, the first phase has a high tende