Research On Control Valves And Its Application In Community’s Hot Water Heating Networks

In hot water heating system’s operation,hot water heating networks’ flow distribution doesn’t meet heat users’ demand because initial adjustment towards hot water networks wasn’t made well during the beginning of heating supply or heat users’ demand changes,leading to hot water heating system’s heat output doesn’t match heat users’ heat requirement and hydraulic disorder of water heat-supply system.Adjustment of water heat-supply networks is the key to solve the hydraulic disorder in heating systems.And it is one of the most effective measures to install control valves which change networks’ resistance in order to reach flow’s reasonable distribution by changing the opening of the regulating valves.Aiming at hot water heating networks’ hydraulic disorder,the paper based on control valves’ fundamental principles and the new transformed valve controlling hot water networks’ hydraulic disorder has done researches on the new control valve’s characteristic of flow and differential pressure in the following aspects:The influence of pump frequency and pressurization point’s pressure on control valve’s characteristic of flow and differential pressure is verified by hydraulic condition control experiments.Verify locking control valves’ constant current characteristic by changing locking control valves’ angle of threads in order to determine control valves’ best angle of threads.Researches are done on control valve’s characteristic of flow and differential pressure under conditions with different valve’s turns,obtaining the correspondent constant flow’s value and and pipeline by changing inflow straight pipe’s length.Inflow straight pipe’s length having the biggest influence on locking control valve’s characteristic is verified by changing inflow straight pipe’s length and testing locking control valve’ performance curves.Then inflow straight pipe’s minimum length in practical installation can be determined.Based on locking control valves’ characteristics of flow and differential pressure,locking control valves are applied into one community’s hot water heating networks to control the networks’ hydraulic disorder practically.Then energy consumption before and after locking regulating valves’ installation are calculated and compared.The influence of pump frequency and pressurization point’s pressure on control valve’s characteristic of flow and differential pressure is excluded through experiments and it’s determined that in locking valves’ practical installation,the angle of threads should be maintained at 135° in order to assure locking valves’ constant flow characteristic.Experiments are conducted about the influence of different inflow straight pipe’s length on locking control valve’s flow and differential pressure characteristic under the DN65 control valve.Meanwhile,locking control valves’ constant flow characteristic under different control turns is achieved.By applying locking control valves to a community’s hot water heating networks,the community’s heating system’s energy consumption before and after installatiion is compared and analyzed.It is concluded that after locking control valves’ installation,the system can achieve good hydralic balance while the system’s power consumption isn’t too large.So it’s necessary to install locking control valves in hot water heating networks to improve the networks’ control performance and achieve the heating system’s hydraulic balance.