Leak detector

Abstract

A leak detector includes a gas sensor and a purge gas supply in fluid communication with a probe head. The fluid communication has a first communication direction for the gas sensor and a second communication direction opposite to the first communication direction for the purge gas supply. The gas sensor and the purge gas supply are configured for communication through a common conduit for the fluid communication with the probe head through one or more probe head ports. Only one of the gas sensor or the purge gas supply can be in fluid communication with the probe head at a time.

What is claimed is: 
     
         1 . A leak detector comprising, a gas sensor and a purge gas supply in fluid communication with a probe head, the fluid communication having a first communication direction for the gas sensor and a second communication direction for the purge gas supply, which communication directions are opposite to each other, wherein the gas sensor and the purge gas supply are configured for communication through a common conduit for the fluid communication with the probe head through one or more probe head ports and wherein only one of the gas sensor or the purge gas supply can be in fluid communication with the probe head at a time. 
     
     
         2 . The leak detector according to  claim 1 , further comprising in communication with the gas sensor a valve for changing the communication direction, wherein the gas sensor is set with a threshold value of content of signal gas in a sample volume, and configured to communicate a change signal to the valve, and wherein the valve is configured to change the communication direction upon receipt of the change signal. 
     
     
         3 . The leak detector according to  claim 2 , further comprising a timer in communication with the valve, wherein the timer is set with a time interval and configured to start upon receipt of a start signal when the valve changes the communication direction towards the gas sensor and further configured to send a change signal to the valve. 
     
     
         4 . The leak detector according to  claim 1 , wherein the probe head comprises one or more probe head ports and a clamp arranged for shifting between an open position for receiving a pipe section and a closed position for enclosing the pipe section and forming a chamber around the pipe section in the closed position, wherein at least one of said probe head ports opens into the inside of the chamber, wherein the probe head comprises activation means for shifting the clamp from the open position to the closed position by interaction with the pipe section, and wherein the activation means comprises one or more activation points configured for mechanically activation of the clamp by an applied force applied to at least one of the activation points, wherein the clamp is gradually closed as a function of the magnitude of the applied force. 
     
     
         5 . The leak detector according to  claim 4 , wherein the clamp is made of an elastic material. 
     
     
         6 . The leak detector according to  claim 5 , wherein the clamp is made of silicone rubber. 
     
     
         7 . The leak detector according to  claim 5 , wherein the clamp comprises an inner part, an outer part having a lower jaw and an upper jaw, and two connection points connecting the upper jaw with the lower jaw, the clamp comprises a transversal opening between the connection points arranged to receive the pipe section, and wherein at least one of the connection points is configured as an activation point configured to be mechanically activated by an applied force directed towards the inner part to shift the clamp from the open position to the closed position by means of deformation of the clamp. 
     
     
         8 . The leak detector according to  claim 4 , further comprising an outer purging conduit in fluid communication with a purging gas supply and the probe head, wherein one or more probe head ports opens to the exterior of the clamp for providing an outer purging of the clamp. 
     
     
         9 . The leak detector according to  claim 4 , further comprising a position sensor for detecting the position of the pipe section relative to the clamp and one or more transduces in communication with the position sensor, wherein the position sensor is configured to communicate a stop signal and the one or more transduces are configured to output an optical and/or acoustic signal upon receipt of the stop signal. 
     
     
         10 . The leak detector according to  claim 4 , further comprising a dampening unit adapted to be set with a threshold force value and configured to regulate the position of the probe head relative to the pipe section as a function of the applied force to the one or more activation points. 
     
     
         11 . A method of leak testing a pipe joint using a leak detector according to  claim 1 , the method comprising acts of:
 arranging the probe head at a distance of a pipe joint to be leak tested;   supplying a purge gas from the purge gas supply via the common conduit to purge an area surrounding or partly surrounding the pipe joint;   reverting the communication direction in the common conduit to perform suction of one or more sample volumes from the area surrounding or partly surrounding the pipe joint;   performing continuously measurements of content of a signal gas in the one or more sample volume, and   reverting the communication direction in the common conduit to supply purge gas when a threshold value of content of signal gas in a sample volume or a set time-interval is reached.   
     
     
         12 . The method according to  claim 11 , wherein the leak detector further comprises a probe head with a clamp for enclosing the pipe joint and forming a chamber, and an outer purging conduit in fluid communication with a purge gas supply and the probe head for providing an outer purging external to the clamp, said method comprising a further act of applying an outer purging external to the clamp at least during the act of performing continuously measurements of content of a signal gas in the sample volume. 
     
     
         13 . The method according to  claim 11 , wherein the leak testing is conducted for pipe systems in refrigerators, freezers, AC units, AC in cars for detecting the signal gas or the refrigerant applied to the pipe system during the leak test.