The Saxophone is sometimes referred to as a brass instrument. That is wrong, even if the instrument indeed is made out of brass material. The Saxophone is part of the Woodwind family among instruments like the flute and the clarinet.
However, the burning question here is: Do Saxophone Have Spit Valves? The answer is No, Saxophones do not generally have Spit valves. But, there are two exceptions.
The Baritone and Bass saxophones, which are the two of the bigger saxophone types do have Spit Valves. That's because of their construction and the difficulty of cleaning out the extra bend on the neck connector.
Spit Valves are something you normally find on Trumpets, Trombones, Tubas, French Horns and other brass instruments.
The saxophone body and neck is made of brass, but that does not make the sax a part of the brass family and here is why:
In order to get any sound from the saxophone you need a mouthpiece connected to the neck and body of the saxophone. On the mouthpiece you have to use a saxophone reed which is the actual source of the sound.
When you blow air into the saxophone mouthpiece (with the reed attached) it will make the reed vibrate and that's how you get the saxophone sound.
In order to play different notes on the sax you combine the mouthpiece blowing, also referred to as the embouchure, with different fingerings on the sax keys.
Those different combinations of keys will produce different notes as long as you keep blowing air through the mouthpiece.
It's quite common, especially among beginners, to get a spitty sound while playing the saxophone. However, that is something you need to adress without a spit valve.
There could be a number of reasons why you get a lot of spit into the mouthpiece but in my experience, as a saxophone teacher of 20+ years, it usually comes down to an uncontrolled embouchure.
In other words, the way you blow into the mouthpiece.
You can get rid of the spit and that raspy sound by cleaning the mouthpiece and then start focusing on developing a solid embouchure.
That will greatly reduce the amount of saliva and spit you blow into the mouthpiece. As a result, you will develop a much better sax sound.