The Washington Capitals took 19 players, more than their combined total in the past two years, in yesterday's National Hockey League draft of amateur players.

The Capitals signed their first choice, center Ryan Walter of the Seattle Breakers, to a multiyear contract. They grabbed what General Manager Max Mcnab called "the two best Swedes" and a goalie Richard Sirois, winger Bob's brother, in evident practice of their "family" concept.

Washington's key Nos. 18, 20 and 23 selections were Tom Coulis, a right wing from Hamilton with a reputation for rough stuff; Paul Mulvey, a 6-foot-4, 219-pound left wing from Portland, and Paul MacKinnon, a hard-rock defense man for Peterborough's Memorial Cup finalists.

Coulis was obtained with the choice obtained for $30,000 in lieu of selecting a player from the Minnesota-Cleveland combined roster. Coulis is considered to have more potential than the unprotected major leaguers, if he can be harnessed.

"As far as the franchise is concerned, we got the best couple available," McNab said. "Ryan Walter's attitude and maturity are remarkable, and his courage and agressiveness are unquestions. Tim Coulis also has a shot at making the club this year. He was rated No. 10 by Central Scouting."

Chief Scout Red Sullivan had praised for Mulvey, brother of Chicago scrapper Grant Mulvey.

"He had 43 goals playing on Portland's No. 1 line and we feel he could be a real steal where we drafted him," Sullivan said. "He wants to play badly. His skating is a little rough now, but that's true of most big guys his age. Peter Mahovlich was that way and look at him skate now."

Walter, who captained the Canadian team in the World Junior Tournament, is considered a sure thing for future stardom.

"He's the type of hockey player with the leadership qualities we've been looking for," Sullivan said. "He's a great player in the dressing room as well as on the ice.He's the best checker in junior hockey, and I mean checking on the NHL level.

Sullivan compared Walter to Philadelphia's Bobby Clarke: "He's better and stronger than Clarke and he has probably more stamina, if that's possible. His leadership qualities are on a par with Clarke. He has all the attributes to be a great captain."

Walter, a Vancouver native, attended the draft in the grand ballroom of the Queen Elizabeth Hotel with his parents.

"This is a very exciting day for me," Walter said. "I've been working for this a long time. I'm glad to be with Washington, because they're going with younger players. I think the club has a great future."

Lou Franceschetti, a left wing from Niagara Falls drafted in the fifth round, voiced similar sentiments.

"I had hoped to go in the low second or high third round," Franceschetti said, "but you have to be patient. I'm glad I'm going to a team that needs help. I'll get a good look."

MacKinnon, although only the 23rd choice, was a dinner guest, with his parents, of McNab during the Stanley Cup playoffs, which illustrates the extent of the Capitals' scouting procedures.

"He's never really said anything about drafting me," MacKinnon said. "I'm very pleased it turned out this way. I've heard Tom McVie is kind of a physical-fitness nut, but I've played for some pretty discipline-minded coaches in Roger Neilson and Gary Green. It's a lot different up there and I definitely have to count on being in the minors for a while, but I think I can make it."

MacKinnon's Peterborough team beat Ottawa in a memorable playoff series this year. Ottawa's superstar center, Bob Smith, was the first player drafted yesterday, by Minnesota.

A total of 234 players was drafted, with 20-year-olds from the Soviet Union, Czechoslovakia, Finland and West Germany, and a plethora of Swedes included.

All except two Cleveland players will follow the Barons to Minnesota. In a dispersal draft, Randy Holt, a right winger and defenseman, was chosen by Vancouver and Mike Crombeen, the Baron's No. 1 draft choice last year, was taken by St. Louis.

The big Washington crop, after only eight picks in 1976 and 10 last year, included the first foreign players drafted by the Capitals - Swedish forwards Bengt-Ake Gustavsson and Mats Hallin. Also, McNab grabbed Sirois and defenseman Mark Toffolo, 1977 draftees who did not sign pro contracts.

Sirois, troubled by a bad back last season, rejected a Buffalo contract bid Sunday and elected to take his chances in another draft.

"The Capitals now have a goaltender goon," said brother Bobby, laughing about Richard Sirois's 80 penalty minutes in the International League. "Seriously, I have confidence in my brother. He's good. And if the Capitals are interested, I have a sister, too."