Equilibrium piston valve for brass instruments

A piston valve device for adjusting the length of tubing in a musical instrument, the device comprising:

• a. a piston casing for holding a piston cylinder, the piston casing being comprised of four ports arranged on a port level around a perimeter of the piston casing, coinciding to four attached air tubes, wherein;
• i. a first air tube is a mouthpiece tube, connecting a mouthpiece to the piston valve;
• ii. a second air tube is an attachment-out tube, connecting the piston-valve to an attachment tube;
• iii. a third air tube is an attachment-in tube, connecting the attachment tube back to the piston valve, and
• iv. a fourth air tube is a bell tube, connecting the piston valve to a bell;
• b. a piston cylinder having a height, wherein the piston cylinder is positioned within the piston casing, and the piston cylinder is comprised of three air passages, wherein;
• i. a first air passage is on a first level of the piston cylinder, a second air passage is on a second level of the piston cylinder, and a third air passage is also on the second level of the piston cylinder;
• ii. the first air passage travels straight through the piston cylinder at a 180-degree angle, connecting the mouthpiece tube to the bell tube;
• iii. the second air passage travels through the piston cylinder at a slight bend no more acute than a 155-degree angle, connecting the mouthpiece tube to the attachment-out tube;
• and
• iv. the third air passage travels through the piston cylinder at a slight bend no more acute than a 155-degree angle, connecting the attachment-in tube to the bell tube;
• and
• c. a means for actuating the piston between a disengaged position and an engaged position.